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Topic: Putting Limits on the Diversity of Life
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Fernando Castro-Chavez
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posted 10. April 2004 18:30
Putting Limits on the Diversity of Life.
(Part Four. Continued... 3)
Philos Trans R Soc Lond B Biol Sci. 2002 Apr 29;357(1420):471-92. Host races in plant-feeding
insects and their importance in sympatric speciation. Dres M, Mallet J.
"We recognize host races as kinds of species that regularly exchange genes…" "Host races provide a convenient, although admittedly somewhat arbitrary intermediate stage along the speciation continuum." "We apply this criterion to 21 putative host race systems. Of these, only three are unambiguously classified as host races, but a further eight are strong candidates that merely lack accurate information on rates of hybridization or gene flow. Thus, over one-half of the cases that we review are probably or certainly host races, under our definition."
Nature. 2002 May 23;417(6887):440-3. Host-plant adaptation drives the parallel evolution of
reproductive isolation. Nosil P, Crespi BJ, Sandoval CP.
"The parallel evolution of reproductive isolation provides strong evidence for natural selection in the process of speciation, but only one… example from nature is known. Populations of the walking-stick insect Timema cristinae…" "…divergent selection for host adaptation, and not genetic drift…"
Genome Res. 2002 May;12(5):729-38. Structure and evolution of the Smith-Magenis syndrome repeat gene clusters, SMS-REPs. Park et al.
"The SMS-REP LCRs are highly homologous (>98%) and contain at least 14 genes/pseudogenes each. SMS-REPs are not present in mice [but in primates]"
Evolution Int J Org Evolution. 2002 Mar;56(3):597-616. Discovery and phylogenetic analysis of a riverine species flock of African electric fishes (Mormyridae: Teleostei). Sullivan et al.
"The evolution of species-specific mate recognition signals is of particular interest within speciose
monophyletic groups with restricted distributions (known as "species flocks"). However, the explosive nature of speciation in these clades makes difficult the reconstruction of their phylogenetic history" "…we recognize 38 forms that are distinct in their morphologies and electric organ discharge (EOD) characteristics. Of these 38, only four clearly correspond to described species" "…we infer an incongruence between the mitochondrial gene tree and the organismal phylogeny…"
Evolution Int J Org Evolution. 2002 Mar;56(3):527-45. Divergence of mitochondrial dna is not corroborated by nuclear dna, morphology, or behavior in Drosophila simulans. Ballard et al.
"Evidence presented in this study suggests that mtDNA is not a good indicator of organismal subdivision in D. simulans. Furthermore, there is no evidence to suggest that Wolbachia causes any reduction in nuclear gene flow in this species. The observed differentiation in mtDNA is not corroborated by data from NADH: ubiquinone reductase 75kD subunit precursor or the Alcohol dehydrogenase-related loci, from the shape or size of the male genital arch, or from assortative premating behavior." "We conclude with an iterated appeal to include phylogenetic and statistical tests of neutrality as a supplement to phylogenetic and population genetic analyses when using mtDNA…"
Mol Biol Evol. 2002 Jul;19(7):1100-13. Contrasting rates of mitochondrial molecular evolution in
parasitic Diptera and Hymenoptera. Castro LR, Austin AD, Dowton M.
"Relative rate tests indicated generally that the parasitic lifestyle was not associated with an
increased rate of genetic divergence in the Diptera but reaffirmed that it was in the Hymenoptera.
Similarly, a departure from compositional stationarity was not associated with parasitic Diptera but was in parasitic Hymenoptera. Finally, mitochondrial (mt) gene rearrangements were not observed in any of the dipteran species examined. The results indicate that these genetic phenomena are not accelerated in parasitic Diptera compared with nonparasitic Diptera."
Proc R Soc Lond B Biol Sci. 2002 Jun 22;269(1497):1301-5. The evolution of parasites from
their hosts: intra- and interspecific parasitism and Emery's rule. Lowe RM, Ward SA, Crozier RH.
"…either the rarer or the commoner species may become the parasite…"
Trends Genet. 2002 May;18(5):259-64. The rise and fall of SRY. Marshall Graves JA.
"…it is dispensable, having been lost at least twice independently in different rodent lineages."
Philos Trans R Soc Lond B Biol Sci. 2002 Apr 29;357(1420):493-503. Bird song, ecology and
speciation. Slabbekoorn H, Smith TB.
"The study of bird song dialects was once considered the most promising approach for investigating the role of behaviour in reproductive divergence and speciation. However, after a series of studies yielding conflicting results, research in the field slowed significantly. Recent findings, on how ecological factors may lead to divergence in both song and morphology, necessitate a re-examination. We focus primarily on species with learned song, examine
conflicting results in the literature and propose some potential new directions for future studies." "In analysing the role of song learning in reproductive divergence, we focus on post-dispersal plasticity in a conceptual framework."
Syst Biol. 2000 Sep;49(3):383-99. Seabird and louse coevolution: complex histories revealed by 12S rRNA sequences and reconciliation analyses. Paterson AM, Wallis GP, Wallis LJ, Gray RD.
"The number of cospeciation events was significantly more than would be expected from chance alone (P < 0.01)"
To be Continued....
[ 12. April 2004, 17:40: Message edited by: Fernando Castro-Chavez ]
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Fernando Castro-Chavez
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posted 10. April 2004 18:35
Putting Limits on the Diversity of Life.
(Part Four. Continued... 4)
Trends Parasitol. 2002 Mar;18(3):121-4. When is a parasite species a species? Kunz W. [Comment in: Trends Parasitol. 2002 Oct;18(10):439-40; author reply 440.]
“Regrettably, 140 years after the publication of Darwin's Origin of Species, we face the grotesque situation that we still do not know what is a species whose origin Darwin wanted to explain.”
Proc Natl Acad Sci U S A. 2001 Jun 5;98(12):6714-9. A locus for female discrimination behavior causing sexual isolation in Drosophila. Doi et al.
“The genetic basis of sexual isolation that contributes to speciation is one of the unsolved questions in evolutionary biology.”
Science. 2001 Mar 2;291(5509):1742-8. Genetic clues to dispersal in human populations: retracing the past from the present. Cann RL
“Because of automated technologies and linkage analysis, we are poised to harvest a wealth of information about our past, if we are successful in moving beyond a current polarization regarding models of human evolution. Rather than just suggesting that true resolution will only come by considering fossil or archaeological evidence, the realistic and appropriate application of genetic models for analysis of population structure is also necessary.”
Nature. 2001 Feb 8;409(6821):707-10. Wolbachia-induced incompatibility precedes other hybrid incompatibilities in Nasonia. Bordenstein SR, O'Hara FP, Werren JH. [Comment in: Nature. 2001 Feb 8;409(6821):675-7.]
“Wolbachia are cytoplasmically inherited bacteria that cause a number of reproductive alterations in insects, including cytoplasmic incompatibility, an incompatibility between sperm and egg that results in loss of sperm chromosomes following fertilization. Wolbachia are estimated to infect 15-20% of all insect species, and also are common in arachnids, isopods and nematodes. Therefore, Wolbachia-induced cytoplasmic incompatibility could be an important factor promoting rapid speciation in invertebrates, although this contention is controversial.” “The presence of Wolbachia severely reduces the frequency of hybrid offspring in interspecies crosses. However, antibiotic curing of the insects results in production of hybrids. Furthermore, F1 and F2 hybrids are completely viable and fertile, indicating the absence of F1 and F2 hybrid breakdown [between the parasitic wasps Nasonia giraulti and Nasonia longicornis].”
Evolution Int J Org Evolution. 2001 Jun;55(6):1077-84. Perspective: From mutants to mechanisms? Assessing the candidate gene paradigm in evolutionary biology. Haag ES, True JR.
“Examples come from both plants and animals, and range from intraspecific to interordinal taxonomic ranges. The use of mutationally defined candidate genes to predict evolutionary mechanisms has so far been most fruitful in explaining intraspecific variants, where it has been effective in both plants and animals. In several cases these efforts were facilitated or supported by parallel results from quantitative trait loci studies, in which natural alleles controlling continuous variation in developmental model organisms were mapped to mutationally defined genes. However, despite these successes the approach's utility seems to rapidly decay as a function of phylogenetic distance. This suggests that the divergence of developmental genetic systems is great even in closely related organisms and may become intractable at larger distances. We discuss this result in the context of what it teaches us about development, the future prospects of the candidate gene approach…”
Trends Genet. 2002 Feb;18(2):74-82. Genome architecture, rearrangements and genomic disorders. Stankiewicz P, Lupski JR.
“An increasing number of human diseases are recognized to result from recurrent DNA rearrangements involving unstable genomic regions. These are termed genomic disorders, in which the clinical phenotype is a consequence of abnormal dosage of gene(s) located within the rearranged genomic fragments. Both inter- and intrachromosomal rearrangements are facilitated by the presence of region-specific low-copy repeats (LCRs) and result from nonallelic homologous recombination (NAHR) between paralogous genomic segments. LCRs usually span approximately 10-400 kb of genomic DNA, share >or= 97% sequence identity, and provide the substrates for homologous recombination, thus predisposing the region to rearrangements.”
Heredity. 2001 Nov;87(Pt 5):522-9. Multiplicity of infection and the evolution of hybrid incompatibility in segmented viruses. Frank SA.
“Some viral genomes are divided into segments. When multiple viruses infect a single cell, progeny form by reassorted mixtures of genomic segments. Hybrid incompatibilities arise when a progeny virus has incompatible segments from different parental viruses. Hybrid incompatibility has been observed in influenza and in the multiparticle plant virus Dianthovirus.” “This paper presents mathematical and computer simulation models to study hybrid incompatibility between diverging strains. The models identify multiplicity of infection as a key factor. When many viral particles infect each host cell, the effective ploidy of the genetic system is high. High ploidy dilutes the contribution of each locus to the phenotype, weakening the selective intensity on each locus. Weaker selection on variant alleles allows the population to maintain greater genetic diversity and to be more easily perturbed by stochastic fluctuations. Greater diversity and stochastic fluctuations explore more widely the space of epistatic interactions, causing more frequent shifts among favoured combinations of alleles. Variable ploidy of viral genetics differs from standard Mendelian genetics.”
Proc R Soc Lond B Biol Sci. 2001 Dec 22;268(1485):2515-23. Ancient mitochondrial DNA and morphology elucidate an extinct island radiation of Indian Ocean giant tortoises (Cylindraspis). Austin JJ, Arnold EN.
“…extinct vertebrates, the endemic tortoises (Cylindraspis) of the Mascarene Islands in the Indian Ocean. Mitochondrial DNA corroborates morphological evidence that there were five species of tortoise…” “The history of Mascarene tortoises contrasts with that of the Galapagos, where only a single species is present and surviving populations are genetically much more similar. However, they too show some reduction in anti-predator mechanisms and multiple development of populations with saddlebacked shells.”
Toxicon. 2001 Dec;39(12):1899-916. Venomous cone snails: molecular phylogeny and the generation of toxin diversity. Espiritu DJ, Watkins M, Dia-Monje V, Cartier GE, Cruz LJ, Olivera BM.
“'Focal hypermutation': This sudden, almost saltatory change in sequence is always restricted to the mature toxin region… is a remarkable, mechanistically unexplained and specialized feature of Conus peptide diversification”
Heredity. 2001 Apr;86(Pt 4):439-50. Is the decline of desert bighorn sheep from infectious disease the result of low MHC variation? Gutierrez-Espeleta et al.
“Bighorn sheep populations have greatly declined in numbers and distribution since European settlement, primarily because of high susceptibility to infectious diseases transmitted to them from domestic livestock. It has been suggested that low variation at major histocompatibility complex (MHC) genes, the most important genetic aspect of the vertebrate immune system, may result in high susceptibility to infectious disease. Therefore, we examined genetic polymorphism at a MHC gene (Ovca-DRB) in a large sample, both numerically and geographically, of bighorn sheep. Strikingly, there were 21 different alleles that showed extensive nucleotide and amino acid sequence divergence. In other words, low MHC variation does not appear to be the basis of the high disease susceptibility and decline in bighorn sheep.”
Genome Res. 2001 Jun;11(6):1018-33. The 1.4-Mb CMT1A duplication/HNPP deletion genomic region reveals unique genome architectural features and provides insights into the recent evolution of new genes. Inoue et al.
“CMT1A and HNPP exemplify a paradigm for genomic disorders wherein unique genome architectural features result in susceptibility to DNA rearrangements that cause disease” “…low recombination frequency in males may enable a chromosomal misalignment at proximal and distal CMT1A-REPs and promote unequal crossing over, which occurs 10 times more frequently in male meiosis.”
Appl Environ Microbiol. 2001 Aug;67(8):3501-13. Rapid evolution of a sexual reproduction gene in centric diatoms of the genus Thalassiosira. Armbrust EV, Galindo HM.
“Sexual reproduction is commonly assumed to occur in the vast majority of diatoms due to the intimate association of this process with cell size control. Surprisingly, however, little is known about the impact of sexual events on diatom population dynamics.” “The Sig1 genes of the four closely related Thalassiosira species also displayed high levels of sequence divergence compared to the levels observed with a second gene, Fcp, probably explaining why Sig1 could not be amplified from more distantly related species.”
Heredity. 2001 Feb;86(Pt 2):195-205. Roles of lineage sorting and phylogenetic relationship in the genetic diversity at the self-incompatibility locus of Solanaceae. Lu Y.
“Using the mean terminal branch lengths of trans-specific alleles on the allelic genealogy to infer phylogenetic relationship among species, P. longifolia was found to be more closely related to P. cinerascens than to P. crassifolia. Nonetheless, the distribution of terminal branch lengths of P. longifolia was more similar to that of P. crassifolia than to that of P. cinerascens, suggesting phylogenetic relationship may have little effect on species-specific polymorphism. Similar habitat and growth characters, yet contrasting S-polymorphism, between P. longifolia and P. cinerascens also reject previous hypotheses that habitat and growth characters are the major factors responsible for interspecific differences in S-polymorphism. A likely scenario is that species-specific S-polymorphism is based on lineage sorting whose effect is further modified by species age and historical changes in population parameters.”
Proc Natl Acad Sci U S A. 2001 May 22;98(11):6233-40. Evolution of genome-phenome diversity under environmental stress. Nevo E.
“The genomic era revolutionized evolutionary biology. The enigma of genotypic-phenotypic diversity… was central in the research program of the Institute of Evolution, University of Haifa, since 1975.” “We advanced ecological genetics into ecological genomics and analyzed globally ecological, demographic, and life history variables in 1,200 diverse species across life, thousands of populations, and tens of thousands of individuals tested mostly for allozyme and partly for DNA diversity.” “The organization and evolution of molecular and organismal diversity in nature at global, regional, and local scales are nonrandom and structured; display regularities across life; and are positively correlated with, and partly predictable by, abiotic and biotic environmental heterogeneity and stress… overriding, the effects of mutation, migration, and stochasticity.”
Mol Biol Evol. 2001 Jun;18(6):975-81. Host-associated speciation in a coral-inhabiting barnacle. Mokady O, Brickner I.
“Little morphological variability was revealed between barnacles collected from two morphs of the hydrocoral Millepora dichotoma (encrusting or branching) or from its congener Millepora platyphylla, but a molecular analysis revealed an unexpected pattern of DNA sequence divergence.”
Proc R Soc Lond B Biol Sci. 2001 Jun 22;268(1473):1297-306. Evolutionary history and speciation modes in the cyprinid genus Barbus. Machordom A, Doadrio I.
“…the relationships between the proposed lineages also show that genome duplication may be considered as a homoplasic character since it must have occurred over at least three independent periods and/or in three independent areas. In relation to the possible saltational evolutionary model for the polyploid species examined here, it was found that, although feasible at the nuclear level, the mitochondrial markers looked at do not appear to have undergone this type of evolution. Rather, they seem to have experienced more or less constant change through time.”
Mol Biol Evol. 2001 Sep;18(9):1789-99. Ongoing evolution of strand composition in bacterial genomes. Rocha EP, Danchin A.
“We tried to identify the substitutions involved in the establishment of replication strand bias, which has been recognized as an important evolutionary factor in the evolution of bacterial genomes. First, we analyzed the composition asymmetry of 28 complete bacterial genomes and used it to test the possibility that asymmetric deamination of cytosine might be at the origin of the bias. The model showed significant correlation to the data but left unexplained a significant portion of the variance and indicated a systematic underestimation of GC skews in comparison with TA skews. Second, we analyzed the substitutions acting on the genes from five fully sequenced Chlamydia genomes that had not suffered strand switch…”
J Bacteriol. 2002 May;184(10):2626-33. The evolving genome of Salmonella enterica serovar Pullorum. Liu GR, Rahn A, Liu WQ, Sanderson KE, Johnston RN, Liu SL.
“…the genome of S. enterica serovar Pullorum RKS5078 is organized very differently from the majority of salmonellas, with three major inversions and one translocation. This extraordinary genome structure was seen in most S. enterica serovar Pullorum strains examined, with different structures in a minority of S. enterica serovar Pullorum strains. We describe the coexistence of different genome structures among the same bacteria as genomic plasticity.”
Syst Biol. 1997 Dec;46(4):622-53. Molecular systematics of the Canidae. Wayne RK, Geffen E, Girman DJ, Koepfli KP, Lau LM, Marshall CR.
“Despite numerous systematic studies, the relationships among many species within the dog family, Canidae, remain unresolved.” “…the taxonomically rich canidae fauna of South America and the development in three species of the trenchant heel, a unique meat-cutting blade on the lower first molar” “…the fossil record provides little evidence for the origins of divergent South American species such as the maned wolf and the bush dog” “We attempted to resolve these two issues and five other specific taxonomic controversies by phylogenetic analysis of 2,001 base pairs of mitochondrial DNA (mtDNA) sequence data from 23 canidae species” “…an important chapter… remains to be discovered in the fossil record…” “The origin of the trenchant heel is not well resolved by our data, although the maximum parsimony tree is weakly consistent with a single origin followed by multiple losses of the character in several extant species.”
Proc R Soc Lond B Biol Sci. 2002 Apr 22;269(1493):793-9. Bantu language trees reflect the spread of farming across sub-Saharan Africa: a maximum-parsimony analysis. Holden CJ.
“The Bantu language tree reflects the spread of farming across this part of sub-Saharan Africa between ca. 3000 BC and AD 500. Modern Bantu subgroups, defined by clades on parsimony trees, mirror the earliest farming traditions both geographically and temporally. This suggests that the major subgroups of modern Bantu stem from the Neolithic and Early Iron Age, with little subsequent movement by speech communities.”
J Biosci. 2002 Feb;27(1 Suppl 1):27-33. Horizontal gene transfer and bacterial diversity. Dutta C, Pan A.
“Bacterial genomes are extremely dynamic and mosaic in nature. A substantial amount of genetic information is inserted into or deleted from such genomes through the process of horizontal transfer. Through the introduction of novel physiological traits from distantly related organisms, horizontal gene transfer often causes drastic changes in the ecological and pathogenic character of bacterial species…”
Evolution Int J Org Evolution. 2002 Feb;56(2):322-9. A test of ecologically dependent postmating isolation between sympatric sticklebacks. Rundle HD.
“I tested a prediction of the ecological model concerning the fitness of hybrids between two young, sympatric species of threespine sticklebacks (Benthics and Limnetics). The two species are ecologically and morphologically divergent: the Benthic is adapted to feeding on invertebrates in the littoral zone of the lake whereas the Limnetic is adapted to feeding on zooplankton in the open water. The growth rate of two types of hybrids, the Benthic backcross and the Limnetic backcross, as well as both parent species, was evaluated in enclosures in both parental habitats in the lake. The use of backcrosses is ideal because a comparison of their growth rates in the two habitats estimates an ecologically dependent component of their fitness while controlling for any intrinsic genetic incompatibilities that may exist between the Benthic and Limnetic genomes. The backcross results revealed a striking pattern of ecological dependence: in the littoral zone, Benthic backcrosses grew at approximately twice the rate of Limnetic backcrosses, while in the open water, Limnetic backcrosses grew at approximately twice the rate of Benthic backcrosses.” “Although the rank order of growth rates of all cross-types in the littoral zone was Benthic > Benthic backcross > Limnetic backcross > Limnetic, neither backcross differed significantly from the parent from which it was mainly derived.” “Results in the open water were less clear and were not fully consistent with the ecological model of speciation…”
EXS. 2002;(92):237-45. The use of physiological data to corroborate cospeciation events in symbiosis. Nishiguchi MK.
“Both host and symbiont can be cultured separately, providing a new avenue to test phylogenetic congruence through molecular and physiological techniques.”
Mol Ecol. 2002 Mar;11(3):619-25. Speciation via introgressive hybridization in East African cichlids? Salzburger W, Baric S, Sturmbauer C.
“…a mosaic of alleles derived from both parental lineages…” “…increase of genetic and phenotypic diversity due to hybridization…”
Mol Ecol. 2002 Mar;11(3):387-405. The discovery of three genetic races of the dwarf mistletoe Arceuthobium americanum (Viscaceae) provides insight into the evolution of parasitic angiosperms. Jerome CA, Ford BA.
“…host identity, geographical isolation and environmental factors have contributed to race formation in A. americanum.” “Given sufficient time, it is possible that these races will become reproductively isolated…”
Evolution Int J Org Evolution. 2002 Jan;56(1):58-69. Episodic chromosomal evolution in Planipapillus (Onychophora: Peripatopsidae): a phylogenetic approach to evolutionary dynamics and speciation. Rockman MV, Rowell DM.
“Planipapillus, a clade of onychophorans from southeastern Australia, exhibits substantial chromosomal variation. In the context of a robust phylogeny based on nuclear and mitochondrial sequence data, we evaluate models… that differ in the roles assigned to selection, mutation, and drift.” “A likelihood-ratio test approach, which is independent of our point estimates of ancestral states, rejects an evolutionary model in which the mutation rate is constant and centric fusions are effectively neutral.”
Evolution Int J Org Evolution. 2002 Jan;56(1):191-8. Molecular correlates of reproductive isolation. Fitzpatrick BM.
“Evolution of reproductive isolation as a byproduct of genetic divergence in isolated populations is the dominant (albeit not exclusive) mode of speciation in sexual animals. But little is known about the factors linking speciation to general divergence. Several authors have argued that allopatric speciation should proceed more rapidly if isolated populations also experience divergent selection. Reproductive isolation between allopatric populations is not subject to direct selection; it can accumulate only by random drift or as a fortuitous byproduct of selection on other traits.”
Evolution Int J Org Evolution. 2002 Jan;56(1):111-20. Patterns of divergence in the effects of mating on female reproductive performance in flour beetles. Nilsson T, Fricke C, Arnqvist G.
“We performed an experiment designed to assess genetic divergence in the effects of mating on female reproductive performance in flour beetles, Tribolium castaneum. Females were mated to males of three different wild-type genotypes at two different frequencies, in all possible reciprocal combinations. Male genotype affected all aspects of female reproduction, through its effects on female longevity, total offspring production, reproductive rate, mating rate, and fertility. Moreover, male and female genotype interacted in their effects on offspring production and reproductive rate.”
Biochem Genet. 2001 Dec;39(11-12):395-406. Phylogenetics of freshwater black basses (Centrarchidae: Micropterus) inferred from restriction endonuclease analysis of mitochondrial DNA. Johnson RL, Magee JB, Hodge TA.
“Members of the genus Micropterus form a close natural unit with little morphologic and meristic variation.” “The phylogeny inferred from Dollo parsimony cladistic analysis… was inconsistent with published meristic analyses.”
Genetica. 2001;112-113:515-34. Adaptive divergence and the evolution of reproductive isolation in the wild: an empirical demonstration using introduced sockeye salmon. Hendry AP.
“Populations exposed to different ecological environments should diverge for phenotypic traits that influence survival and reproduction” “…immigrants become less fit than residents and… hybrids perform poorly in either environment…” “…sockeye salmon (Oncorhynchus nerka) introduced from a common ancestral source into a new lake system (Lake Washington, Washington). The introduced fish founded several new populations, two of which experience very different environments during breeding and early development (Cedar River v.s. Pleasure Point beach). Over 13 generations, the two populations diverged for adult traits (female body size, male body depth; measured in the wild) and embryo traits (survival to hatching, development rate, size at emergence; measured in a common environment).”
Genetica. 2001;112-113:445-61. Lateral plate evolution in the threespine stickleback: getting nowhere fast. Bell MA.
“Gasterosteus aculeatus is a small Holarctic fish with marine, anadromous, and freshwater populations. Marine and anadromous populations apparently have changed little… and exhibit limited geographical variation.” “Although highly divergent freshwater isolates of G. aculeatus have existed… they have rarely experienced sustained evolutionary divergence leading to formation of widespread, phenotypically distinct species.”
Genetica. 2001;112-113:223-43. Ring species as bridges between microevolution and speciation. Irwin DE, Irwin JH, Price TD.
“Theoretical models… ring species are ideal systems for research into the role of both ecological and geographical differentiation in speciation, but few examples have been studied in detail.”
Evolution Int J Org Evolution. 2001 Dec;55(12):2550-67. A single ancient origin of brood parasitism in African finches: implications for host-parasite coevolution. Sorenson MD, Payne RB.
“…the parasitic finches (Viduidae) are not recently derived from either weavers (Ploceidae) or grassfinches (Estrildidae), but represent a third distinct lineage.” “Our study reduces by one the tally of avian lineages…”
Mol Phylogenet Evol. 2002 Feb;22(2):303-14. Molecular phylogeny of hybridizing species from the genus Spartina Schreb. (Poaceae). Baumel A, Ainouche ML, Bayer RJ, Ainouche AK, Misset MT.
“Interspecific hybridization events have been reported in the genus Spartina Schreb. (Poaceae), involving the east American species Spartina alterniflora…” “…belonging to the same lineage…” “Significant incongruence has been encountered between the waxy based tree and both the ITS and trnT-trnL trees concerning the position of S. densiflora…”
Mol Phylogenet Evol. 2002 Feb;22(2):258-68. Speciation in the globeflower fly Chiastocheta spp. (Diptera: Anthomyiidae) in relation to host plant species, biogeography, and morphology. Despres L, Pettex E, Plaisance V, Pompanon F.
“The species relationship indicated by egg morphology is only partly supported by molecular data. Moreover, a strong discrepancy between nucleotide variation and male genitalia morphology variation was found, particularly within and among European species coexisting on a single host plant.” “We discuss alternative evolutionary scenarios…”
Immunogenetics. 2001 Oct;53(8):695-708. Mhc class I genes of swordtail fishes, Xiphophorus: variation in the number of loci and existence of ancient gene families. Figueroa F, Mayer WE, Sato A, Zaleska-Rutczynska Z, Hess B, Tichy H, Klein J.
“The analysis revealed the existence of multiple loci (at least seven in some individuals) whose numbers vary among the different species and probably also among individuals of the same species. The variation does not seem to bear any relationship to the taxonomy of the genus.”
Nature. 2001 Dec 20-27;414(6866):901-5. The genetic architecture of divergence between threespine stickleback species. Peichel et al.
“The genetic and molecular basis of morphological evolution is poorly understood, particularly in vertebrates. Genetic studies of the differences between naturally occurring vertebrate species have been limited by the expense and difficulty of raising large numbers of animals and the absence of molecular linkage maps for all but a handful of laboratory and domesticated animals.” “Substantial alterations in spine length, armour plate number, and gill raker number are controlled by genetic factors that map to independent chromosome regions. Further study of these regions will help to define the number and type of genetic changes that underlie morphological diversification…”
Evolution Int J Org Evolution. 2001 Oct;55(10):1932-42. Evidence for Dobzhansky-Muller incompatibilites contributing to the sterility of hybrids between Mimulus guttatus and M. nasutus. Fishman L, Willis JH.
“Both chromosomal rearrangements and negative interactions among loci (Dobzhansky-Muller incompatibilities) have been advanced as the genetic mechanism underlying the sterility of interspecific hybrids” “…we investigated the quantitative genetics of hybrid sterility in a line cross between two members of the Mimulus guttatus species complex (M. guttatus and M. nasutus). Hybrids showed partial male and female sterility, and the patterns of infertility were not consistent with the action of chromosomal rearrangements alone.” “Dobzhansky-Muller interactions also resulted in the breakdown of several nonreproductive characters and appear to contribute to correlations between male and female fertility in the F2 generation. These results parallel and contrast with the genetics of postzygotic isolation in model animal systems and are a first step toward understanding…”
Environ Mol Mutagen. 2001;38(2-3):248-60. Three R's of bacterial evolution: how replication, repair, and recombination frame the origin of species. Brown EW, LeClerc JE, Kotewicz ML, Cebula TA.
“The genetic diversity of bacteria results not only from errors in DNA replication and repair but from horizontal exchange and recombination of DNA sequences from similar and disparate species as well. New individuals carrying adaptive changes are thus being spawned constantly among the population at large. When new selection pressures appear, these are the individuals that survive, at the expense of the general population, to forge new populations.” “We present novel phylogenetic evidence for horizontal transfer of three genes involved in DNA replication and repair (mutS, uvrD, and polA).” “Our data underscore that recombination plays both a diversifying and a homogenizing role in defining the structure of the E. coli genome.”
Mol Ecol. 2001 Oct;10(10):2541-54. Phenotypic evolution and hidden speciation in Candidula unifasciata ssp. (Helicellinae, Gastropoda) inferred by 16S variation and quantitative shell traits. Pfenninger M, Magnin F.
“In C. unifasciata, no significant association between population pairwise FST estimates and corresponding morphological fixation indices could be detected, indicating independent evolution of the two character sets.”
Genetics. 2001 Nov;159(3):1179-89. Female meiosis drives karyotypic evolution in mammals. Pardo-Manuel de Villena F, Sapienza C. [Erratum in: Genetics 2002 Mar;160(3):1263.]
“Speciation is often accompanied by changes in chromosomal number or form even though such changes significantly reduce the fertility of hybrid intermediates. We have addressed this evolutionary paradox by expanding the principle that nonrandom segregation of chromosomes takes place whenever human or mouse females are heterozygous carriers of Robertsonian translocations, a common form of chromosome rearrangement in mammals.”
Annu Rev Phytopathol. 1999;37:197-246. THE EVOLUTION OF ASEXUAL FUNGI: Reproduction, Speciation and Classification. Taylor J, Jacobson D, Fisher M.
“…asexual or sexual reproductive morphology does not necessarily correlate with clonal or recombining reproductive behavior…” “Although approximately one fifth of described fungi have been thought to be asexual and clonal, recent studies have shown that they are also recombining. Whether a particular pathogen reproduces clonally or by recombination depends on factors relating to its biology and its distribution in space and time. Knowing the identity of species and populations and their reproductive modes, while taking a broad view of pathogen behavior in space and time, should enhance the ability of pathologists to control pathogens and even predict their behavior.”
Protein Sci. 2001 Nov;10(11):2207-18. Characterization of ostrich (Struthio camelus) beta-microseminoprotein (MSP): identification of homologous sequences in EST databases and analysis of their evolution during speciation. Lazure C, Villemure M, Gauthier D, Naude RJ, Mbikay M.
“Noticeably, no beta-microseminoprotein-related gene could be found in the recently completed fruit fly genome…”
Mol Phylogenet Evol. 2001 Oct;21(1):55-71. Molecular phylogenies of fig wasps: partial cocladogenesis of pollinators and parasites. Lopez-Vaamonde et al.
“…there is not perfect congruence of pollinator and parasite phylogenies (for any substantial clade)…
Evolution Int J Org Evolution. 2001 Aug;55(8):1706-9. Mimicry on the QT(L): genetics of speciation in Mimulus. Bleiweiss R.
“Ecological studies suggest that hummingbird-pollinated plants in North America mimic each other to increase visitation by birds. Published quantitative trait locus (QTL) data for two Mimulus species indicate that floral traits associated with hummingbird versus bee pollination results from a few loci with major effects on morphology…”
EMBO J. 2001 Sep 3;20(17):4874-83. Heterologous, splicing-dependent RNA editing in chloroplasts: allotetraploidy provides trans-factors. Schmitz-Linneweber C, Tillich M, Herrmann RG, Maier RM.
“RNA editing is unique among post-transcriptional processes in plastids, as it exhibits extraordinary phylogenetic dynamics leading to species-specific editing site patterns.” “Surprisingly, it turned out that the spinach site is edited in the heterologous nuclear background”
Evolution Int J Org Evolution. 2001 Jun;55(6):1085-94. The evolution of postzygotic isolation: accumulating Dobzhansky-Muller incompatibilities. Orr HA, Turelli M.
“These results let us estimate. albeit crudely, the probability, p, that two diverged sites from different species will contribute to hybrid sterility or inviability.”
Hereditas. 2000;133(3):255-61. Chromosomal rearrangement in autotetraploid plants of Arabidopsis thaliana. Weiss H, Maluszynska J.
“Arabidopsis is believed to be a true diploid (x = 5) with numerous ecotypes (accessions) and only a very few natural polyploid populations reported. Few studies were undertaken to induce polyploidy in Arabidopsis, however none of those gave the cytogenetic characteristics of polyploid plants. Our analysis of chromosome pairing of colchicine-induced autotetraploid Arabidopsis (Wilna ecotype) revealed preferential bivalent pairing in PMCs (pollen mother cells). In order to attempt to explain this phenomenon, first of all more detailed cytogenetic studies of autopolyploid plants have been undertaken…” “…chromosome behaviour in relation to diploidization of autopolyploids and to evaluate the degree of chromosomal rearrangements during this process.”
Evolution Int J Org Evolution. 2001 Apr;55(4):677-83. Evolutionary rates and species diversity in flowering plants. Barraclough TG, Savolainen V.
“Genetic change is a necessary component of speciation, but the relationship between rates of speciation and molecular evolution remains unclear.” “Rates of protein and morphological evolution… correlate… not with species numbers.”
Mol Phylogenet Evol. 2001 May;19(2):187-201. Evolution of the mitochondrial DNA control region and cytochrome b genes and the inference of phylogenetic relationships in the avian genus Lophura (Galliformes). Randi et al.
“Presence of conserved functional motifs in the inferred amino acid sequences, conserved secondary structures of the flanking tRNA(Pro) and tRNA(Thr), and Southern hybridization concordantly suggest that these cyt b represent functional mitochondrial genes and not nuclear transpositions…” “…cyclic changes in late Pleistocene climate and landscape might not have increased rates of speciation in genus Lophura in Sundaland.”
Trends Genet. 2001 May;17(5):237-9. Birth and death of duplicated genes in completely sequenced eukaryotes. Wagner A.
“Gene and genome duplications are commonly regarded as being of major evolutionary significance. But how often does gene duplication occur? And, once duplicated, what are the fates of duplicated genes? How do they contribute to evolution? In a recent article, Lynch and Conery analyze divergence between duplicate genes from six eukaryotic genomes. They estimate the rate of gene duplication, the rate of gene loss after duplication and the strength of selection experienced by duplicate genes. They conclude that although the rate of gene duplications is high, so is the rate of gene loss…”
Evolution Int J Org Evolution. 2001 Mar;55(3):587-97. Cladogenesis and loss of the marine life-history phase in freshwater galaxiid fishes (Osmeriformes: Galaxiidae). Waters JM, Wallis GP.
“Switches from migratory (diadromous) to nonmigratory (freshwater) life histories are known to have occurred repeatedly in some aquatic taxa. However, the significance of the loss of diadromy as an initiator for speciation remains poorly understood.” “Sympatric taxa are not monophyletic, suggesting that their coexistence reflects secondary contact rather than sympatric speciation.” “The divergence (maximum 11.5%) between Tasmanian and New Zealand G. brevipinnis, although large, supports marine dispersal rather than vicariance as the principle biogeographic mechanism on an intercontinental scale.”
Chromosome Res. 2001;9(2):107-20. Comparative chromosome and mitochondrial DNA analyses and phylogenetic relationships within common voles (Microtus, Arvicolidae). Mazurok et al.
“The four species of common voles within the genus Microtus--M. kirgisorum, M. transcaspicus, M. arvalis, and M. rossiaemeridionalis--are so closely related that neither morphological features nor paleontological evidence allow clarification of their phylogeny.” “A comparison of high resolution GTG-banding patterns allows us to ascertain the similarity between the karyotypes of these species, revealing that they are composed of rearrangements of the same chromosomal elements” “…FITCH and KITSCH computer programs were used …”
Mol Biol Evol. 2001 May;18(5):801-11. Molecular evolution of the ocnus and janus genes in the Drosophila melanogaster species subgroup. Parsch et al.
“Genes involved in male fertility are potential targets for sexual selection, and their evolution may play a role in reproductive isolation and speciation. Here we describe a new Drosophila melanogaster gene, ocnus (ocn), that encodes a protein abundant in testes nuclear extracts. RT-PCR indicates that ocn transcription is limited to males and is specific to testes. ocn shares homology with another testis-specific gene, janusB (janB), and is located just distal to janB on chromosome 3. The two genes also share homology with the adjacent janusA (janA) gene…”
Biometrics. 1999 Jun;55(2):355-65. A multiplicative-epistatic model for analyzing interspecific differences in outcrossing species. Wu R, Li B.
“Epistasis may play an important role in evolution and speciation. Under multiplicative interactions between different loci, an analytical model is proposed to estimate genetic parameters at the individual locus level that contribute to interspecific differences in outcrossing species.” “Use of clones offers a tremendous power to test the adequacy of the model. However, the utilization of the model with species that cannot be cloned is also discussed. An example with interspecific hybrids of two forest tree species is used to demonstrate the model.”
Mol Ecol. 2001 Mar;10(3):721-35. The effect of habitat type on speciation rates and range movements in aquatic beetles: inferences from species-level phylogenies. Ribera I, Barraclough TG, Vogler AP.
“The expectation that species turnover is higher in lotic lineages due to their lower dispersal propensity compared to lentic species was not strongly supported.” “We discuss two explanations for our failure to detect differences between the two clades. First, current methods for analysing species-level phylogenies may be sensitive to taxonomic and sampling artefacts.”
Mol Ecol. 2001 Mar;10(3):551-68. The role of hybridization in evolution. Barton NH.
“'Hybrid speciation', in which fit combinations of alleles are established, is more problematic…” “heterosis arises only when traits are additive, whereas the latter two patterns require dominance. Moreover, because adaptation is via substitutions of small effect, Fisher's model does not generate the strong effects of single chromosome regions often observed in species crosses.”
Nature. 2001 Mar 22;410(6827):463-6. Intraspecific competition favours niche width expansion in Drosophila melanogaster. Bolnick DI.
“The relationship between intraspecific competition and diversification is known from theory, and has been used as the foundation for some models of speciation. However, there has been little empirical proof that niches evolve in response to intraspecific competition” “…competition in a population can drive niche expansion…”
Evol Dev. 2000 Mar-Apr;2(2):78-84. Macroevolution is more than repeated rounds of microevolution. Erwin DH. [Comment in: Evol Dev. 2000 Mar-Apr;2(2):61-2.]
“Initially, paleontologists and other evolutionary biologists advanced a variety of non-Darwinian evolutionary processes as explanations for patterns found in the fossil record, emphasizing macroevolution as a source of morphologic novelty. Later, paleontologists, from Simpson to Gould, Stanley, and others, accepted the primacy of natural selection but argued that rapid speciation produced a discontinuity between micro- and macroevolution. This second phase emphasizes the sorting of innovations between species. Other discontinuities appear in the persistence of trends…” “These discontinuities impose a hierarchical structure to evolution and discredit any smooth extrapolation from allelic substitution to large-scale evolutionary patterns…” “…macroevolution… unexplained by microevolution…”
J Gen Virol. 2001 Apr;82(Pt 4):713-22. Evolutionarily conserved RNA secondary structures in coding and non-coding sequences at the 3' end of the hepatitis G virus/GB-virus C genome. Cuceanu NM, Tuplin A, Simmonds P.
“Using a combination of covariance scanning and analysis of variability at synonymous sites, we previously demonstrated that the coding regions of HGV/GBV-C may contain extensive secondary structure of undefined function (Simmonds & Smith, Journal of Virology 73, 5787-5794, 1999 ). In this study we have carried out a detailed comparison of the structure of the 3'untranslated region (3'UTR) of HGV/GBV-C with that of the upstream NS5B coding sequence.” “The prediction of similar structures in the same region of hepatitis C virus may allow the functions of these structures to be determined with a more tractable experimental model.”
Proc R Soc Lond B Biol Sci. 2000 Dec 22;267(1461):2517-21. Intraspecific phylogenetic congruence among multiple symbiont genomes. Funk et al.
“Eukaryotes often form intimate endosymbioses with prokaryotic organisms. Cases in which these symbionts are transmitted cytoplasmically to host progeny…” “This study thus provides the first evidence for strictly vertical transmission…” “These results may reflect the obligate nature of this intimate mutualism…”
Nature. 2001 Jan 11;409(6817):185-8. Correlated evolution of morphology and vocal signal structure in Darwin's finches. Podos J. [Comment in:
Nature. 2001 Jan 11;409(6817):139-40.]
“According to classical theories of speciation, mating signals diversify, in part, as an incidental byproduct of adaptation by natural selection to divergent ecologies, although empirical evidence in support of this hypothesis has been limited…” “…diversification of beak morphology and body size has… patterns of vocal signal… birds with large beaks and body sizes have… songs with comparatively low rates of syllable repetition and narrow frequency bandwidths. The converse is true for small birds.”
Proc Natl Acad Sci U S A. 2001 May 8;98(10):5389-92. The biotic crisis and the future of evolution. Myers N, Knoll AH.
“Not so well known but probably more significant in the long term is that the crisis will surely disrupt and deplete certain basic processes of evolution, with consequences likely to persist for millions of years. Distinctive features of future evolution could include…end to the speciation of large vertebrates…” “Despite this likelihood, we have only a rudimentary understanding of how we are altering the evolutionary future. As a result of our ignorance, conservation policies fail to reflect long-term evolutionary aspects of biodiversity loss.”
Proc Natl Acad Sci U S A. 2001 May 8;98(10):5471-6. Declines of biomes and biotas and the future of evolution. Woodruff DS.
“In response to the on-going rapid decline of biomes and homogenization of biotas, the panelists predicted changes in species geographic ranges, genetic risks of extinction, genetic assimilation, natural selection, mutation rates, the shortening of food chains, the increase in nutrient-enriched niches permitting the ascendancy of microbes, and the differential survival of ecological generalists. Rates of evolutionary processes will change in different groups, and speciation in the larger vertebrates is essentially over” “…interventionist genetic…” “…to better equip us for stewardship of the processes of evolution, and one suggesting that such stewardship is now our responsibility. The ultimate test of evolutionary biology as a science is not whether it solves the riddles of the past but rather whether it enables us to manage the future of the biosphere. Our inability to make clearer predictions about the future of evolution has serious consequences for both biodiversity and humanity.”
Mol Biol Evol. 2001 Mar;18(3):376-83. Polymorphism in abalone fertilization proteins is consistent with the neutral evolution of the egg's receptor for lysin (VERL) and positive darwinian selection of sperm lysin. Swanson WJ, Aquadro CF, Vacquier VD.
“…there was a subdivision in the VERL sequences in the pink abalone and a lack of heterozygous individuals between groups, suggesting that the evolution of assortative mating may be in progress…”
Riv Biol. 2000 Sep-Dec;93(3):513-24. Ontogeny, phylogeny and the origin of biological information. Davison JA.
“Accepting the evidence that evolution is largely finished and that sexual reproduction is incapable of supporting macroevolution… Acceptance of these possibilities…”
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Regarding radioactive ‘speciation’:
Water. 2002 Jan-Feb;40(1):5-13. Natural attenuation reactions at a uranium mill tailings site, western U.S.A. Zhu C, Anderson GM, Burden DS.
“This paper presents a modeling analysis of the geochemical evolution of a contaminated sandy aquifer at a uranium mill tailings site in the western United States.” “For the flushing stage, it is predicted that reactions with surface-bound species will dominate the reaction paths, and more pore volumes are required to neutralize the plume than predicted by models that do not consider surface reactions. Direct mineralogical and surface analysis is needed to substantiate this assertion.”
To be Continued....
[ 12. April 2004, 17:39: Message edited by: Fernando Castro-Chavez ]
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Fernando Castro-Chavez
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posted 13. April 2004 17:19
Putting Limits on the Diversity of Life.
(Part Four. Continued... 5)
‘Speciation’ does not occurred in the present or in the past, neither ‘evolution’.
"You can never solve a problem on the level on which it was created." "A man should look for what is, and not for what he thinks should be." Albert Einstein.
Fragment from: “The Galapagos Islands: Evolution's Sacred Ground, by Ray Bohlin, Ph.D.”
“Most of these six ground finches will interbreed, and the hybrids are fertile, meaning they can also breed among themselves. This information is quite startling because it means that these six species may actually be one species. And the actual degree of change is quite miniscule. The average beak size may change by only a half a millimeter from dry to wet season. These six finches are also indistinguishable in their mtDNA. As an icon of evolution, the finches are far less than hoped for.”
“The marine iguana's cousin, the land iguana eats cactus pads and leafy vegetation and never ventures toward the sea... Evolutionists suggest that these two species derived from a common ancestor over ten to twenty million years ago (although the oldest island is only 3 million years old!). But we learned that these two species would interbreed on occasion. The hybrids live for only seven to eight of the usual forty years, and their eating habits are strangely intermediate. The hybrids will eat cactus but not leafy vegetation, and will eat seaweed and algae but only at low tide when they can scramble over the rocks to get it. They won't enter the water. This level of hybridization makes it unlikely they are as old as evolutionists suggest.”
[Jonathan Wells, Icons of Evolution (Washington, DC: Regnery Publishing 2000), p. 159-175;
http://www.probe.org/docs/galapagos.html]
The fact that evolution is not true can be seen also in Darwin’s finches, they are the same species or kind: “fertile parents = fertile offspring.” Nothing is 'evolving' beyond the natural limits established within the species:
Darwin's Avian Muses Continue To Evolve
Carl Zimmer. Science 26 April 2002; 296: 633-635.
http://www.carlzimmer.com/articles/2002/articles_2002_Finch.html
"The two species on Daphne Major can and sometimes do interbreed, and their hybrids--far from being mulelike reproductive dead ends--are a source of fresh genetic variability." "Interbreeding may be one of the secrets... hybrids may be an unrecognized factor..." "...five male cactus finches for every female. A few desperate males mated with female ground finches, which then produced perfectly healthy and fertile hybrids." "As a result, ground finch genes are flowing into the cactus finch gene pool--a process called introgression--making their beaks blunter." "Other biologists are surprised that two distantly related species can produce healthy hybrids..." "This new source of genetic diversity makes it easier for a species with donated genes to adapt to a changing environment, the Grants claim."
In the words of the researchers themselves:
Grant PR, Grant BR.
Genetics and the origin of bird species.
Proc Natl Acad Sci U S A. 1997 Jul 22;94(15):7768-75. http://www.pnas.org/cgi/content/full/94/15/7768
"...the populations are only partly reproductively isolated, interbreeding occurs, and some of the hybrids survive to breed" "...species hybridize, rarely, and are capable of producing fertile hybrids that backcross to the parental species" "...interbreeding of species and the breeding of hybrids ..."
[Refs: Grant, P. R. & Grant, B. R. (1992) Science 256, 193-197; Grant, P. R. & Grant, B. R. (1997) Biol. J. Linn. Soc. 60, 317-343; Grant, B. R. & Grant, P. R. (1997) in Endless Forms: Species and Speciation, eds. Howard, D. J. & Berlocher, S. H. (Oxford Univ. Press, Oxford)]
"...field observations of natural hybridization have been made on the islands of Daphne Major…”
[Grant, P. R. (1993) Philos. Trans. R. Soc. London Ser. B 340, 127-139, Grant, P. R. & Price, T. D. (1981) Am. Zool. 21, 795-811, Boag, P. T. & Grant, P. R. (1984) Biol. J. Linn. Soc. 22, 243-287]
“…and [the island] Genovesa”
[Grant, B. R. & Grant, P. R. (1989) Evolutionary Dynamics of a Natural Population: The Large Cactus Finch of the Galápagos (Univ. Chicago Press, Chicago)].
“These show that all six species of Darwin's ground finches (genus Geospiza) hybridize (rarely) with at least one other congeneric species. In addition some intergeneric crosses are known among the tree finches and warbler finch, and breeding hybrids have been produced”
[Grant, P. R. (1986) Ecology and Evolution of Darwin's Finches (Princeton Univ. Press, Princeton, N. J.), Bowman, R. I. (1983) in Patterns of Evolution in Galápagos Organisms, eds. Bowman, R. I., Berson, M. & Leviton, A. E. (American Association for the Advancement of Science, San Francisco), pp. 237-537].
On Daphne Major Geospiza fortis (medium ground finch) hybridizes with G. scandens (cactus finch), another resident species, and G. fuliginosa (small ground finch), an uncommon immigrant. Contrary to expectation from the reinforcement hypothesis, hybrids formed by Geospiza fortis breeding with G. scandens and G. fuliginosa are both viable and fertile to a degree similar to that of the contemporary offspring of conspecific matings; so are the first two generations of backcrosses" "Backcrossing negates the hypothesis of speciation occurring entirely in allopatry." "In tests of several species the discrimination was often weak, implying that song difference, by itself, would not be sufficient to prevent interbreeding."
"At the point of ring closure or overlap where two populations establish secondary contact they do not interbreed, or do so extremely rarely; e.g., herring gull and lesser black-backed gull. A crossfostering experiment with these gulls showed that, as in Darwin's finches, misimprinted birds are capable of producing viable hybrids, i.e., once the premating isolating mechanism is broken”
[Harris, M. P. (1970) Ibis 112, 488-498; Harris, M. P., Morley, C. & Green, G. H. (1978) Bird Study 25, 161-166]
Some of the Grant’s’s recent works:
Grant PR, Grant BR, Keller LF, Markert JA, Petren K.
Inbreeding and interbreeding in Darwin's finches.
Evolution Int J Org Evolution. 2003 Dec;57(12):2911-6.
Markert JA, Grant PR, Grant BR, Keller LF, Coombs JL, Petren K.
Neutral locus heterozygosity, inbreeding, and survival in Darwin's ground finches (Geospiza fortis and G. scandens).
Heredity. 2004 Apr;92(4):306-15.
Keller LF, Grant PR, Grant BR, Petren K.
Environmental conditions affect the magnitude of inbreeding depression in survival of Darwin's finches.
Evolution Int J Org Evolution. 2002 Jun;56(6):1229-39.
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More references from the Pubmed search ‘speciation’ and ‘evolution’:
Annu Rev Genet. 2000;34:401-437. Polyploid incidence and evolution. Otto SP, Whitton J.
“…whether polyploidization itself has a significant effect on patterns and rates of diversification remains an open question.” “Theoretical models support the potential for increased adaptability in polyploid lineages” “…yet conclusive evidence that polyploidy has changed rates and patterns of diversification remains elusive.”
Bioessays. 2000 Dec;22(12):1134-41. Dualism and conflicts in understanding speciation. Schilthuizen M.
“Speciation is a central but elusive issue in evolutionary biology. Over the past sixty years, the subject has been studied within a framework conceived by Ernst Mayr and Theodosius Dobzhansky and subsequently developed further by numerous other workers. In this "isolation" theory, the evolution of reproductive isolation is a key element of speciation; natural selection is given only secondary importance while gene flow is considered prohibitive to the process. In this paper, I argue that certain elements in this approach have produced confusion and irreconcilability among students of speciation. The more prominent debates in speciation (i.e., the species definition, sympatry/allopatry, and the role of reinforcement) all derive from an inherent conflict between the "isolation" theory and Darwin's "selection" view on species and speciation (in which disruptive selection is crucial). New data, mainly from field ecology, molecular population genetics, laboratory studies with Drosophila and computer analysis, all suggest that the isolation theory may no longer be the most desirable vantage point from which to explore speciation.” “The traditional preoccupation with reproductive isolation has created gaps in our knowledge of several crucial issues, mainly regarding the role of environmental selection and its connection with mate selection” “…the method [proposed by Schilthuizen M.] under the pure drift model is verified via Monte Carlo simulations.”
Mol Biol Evol. 2000 Apr;17(4):601-15. Evolution of nucleotide substitutions and gene regulation in the amylase multigenes in Drosophila kikkawai and its sibling species. Inomata N, Yamazaki T.
“…we do not know whether there was any evolutionary relationship between the two.”
Proc R Soc Lond B Biol Sci. 2000 Mar 7;267(1442):497-503. The shifting roles of dispersal and vicariance in biogeography. Zink RM, Blackwell-Rago RC, Ronquist F.
“…no cladogram was obtained for which all lineages were congruent.” “An expanded database is now needed to estimate the relative roles of each process” “…much older than typically presumed.”
Cytogenet Cell Genet. 2000;88(3-4):296-304. Comparative cytogenetics of hamsters of the genus Calomyscus. Graphodatsky et al.
“Natural hybrids between individuals with different karyotypes were recorded, and regular chromosome pairing in meiosis was observed in laboratory hybrids.” “There is no unequivocal evidence suggesting the role of chromosomal change in the speciation of the populations of Calomyscus examined.”
Mol Biol Evol. 2000 Jun;17(6):897-907. Phylogenetic analysis under reticulate evolution. Xu S.
“The usual assumption that species have evolved from a common ancestor by a simple branching process--where each branch is genetically isolated--has been challenged by the observation of frequent hybridization between species in natural populations. In fact, most plant species are thought to have hybrid origins. This reticulate pattern of species evolution has posed problems in the definition of speciation and in phylogenetic reconstruction, especially when molecular data are used. As a result, hybridization has been largely treated as an evolutionary accident or statistical error in phylogenetic analysis.”
Proc R Soc Lond B Biol Sci. 2000 Feb 22;267(1441):327-32. The inheritance of female preference functions in a mate recognition system. Ritchie MG.
“Mate recognition systems (MRSs) play a major role in sexual selection and speciation, yet few studies have analysed both male and female components in detail” “…the inheritance of male song and female preference functions followed in crosses between subspecies” “…there is no evidence for a role of maternally derived sex-linked genes in female preference or of maternal effects.”
Plant Cell. 1999 Aug;11(8):1433-44. Molecular analysis of the anthocyanin2 gene of petunia and its role in the evolution of flower color. Quattrocchio et al.
“Analysis of P. axillaris subspecies with white flowers showed that they contain an2(-) alleles with two alternative frameshifts at one site [an2, anthocyanin2 locus, the main determinant of color differences, a regulator of the anthocyanin biosynthetic pathway that encodes a transcription factor, a MYB domain protein], apparently caused by the insertion and subsequent excision of a transposon. A third an2(-) allele has a nonsense mutation elsewhere, indicating that it arose independently.”
Proc R Soc Lond B Biol Sci. 2000 Dec 7;267(1460):2375-84. Historical contingency and ecological determinism interact to prime speciation in sticklebacks, Gasterosteus. Taylor EB, McPhail JD.
“Historical contingency and determinism are often cast as opposing paradigms under which evolutionary diversification operates. It may be, however, that both factors act together to promote evolutionary divergence, although there are few examples of such interaction in nature.” “Sympatric sticklebacks, therefore, provide an example of adaptive radiation by determinism contingent upon historical conditions promoting unique ecological interactions, and illustrate how contingency and determinism may interact to generate geographical variation in species diversity.”
Heredity. 2000 Jan;84 ( Pt 1):97-102. Are the same genes responsible for intra- and interspecific variability for sex comb tooth number in Drosophila? Nuzhdin SV, Reiwitch SG.
“One of the most interesting unresolved puzzles is the relationship between intraspecific variability in morphological traits and their interspecific divergence” “…the vast majority of intraspecific variants could be deleterious mutations … In this case intraspecific variation would not ultimately generate interspecific trait differences.” “Whether or not these effects result from the same genes requires further examination.”
Bioessays. 1999 Dec;21(12):1052-8; discussion 1059. Molecular evidence for the early divergence of placental mammals. Easteal S.
“Paleontological and molecular data suggest quite different patterns…” “Resolving this discrepancy requires a consideration of the assumptions that underlie both approaches. It is argued here that the pattern indicated by the molecular approach is the most likely to be correct.”
Bioessays. 2000 Dec;22(12):1085-94. Speciation by postzygotic isolation: forces, genes and molecules. Orr HA, Presgraves DC.
“…molecular genetic data are limited…”
Mol Phylogenet Evol. 2000 Nov;17(2):244-55. Molecular phylogenetics of the holly leafminers (Diptera: Agromyzidae: Phytomyza): species limits, speciation, and dietary specialization. Scheffer SJ, Wiegmann BM.
“Species boundaries of previously known and of undescribed holly leafmining species were confirmed with the molecular data, with one exception…” “…these traits are evolutionarily labile…”
Curr Opin Chem Biol. 2001 Feb;5(1):86-9. Genome comparisons highlight similarity and diversity within the eukaryotic kingdoms. Ball CA, Cherry JM.
“…duplicate gene pairs in Saccharomyces, Arabidopsis, Caenorhabditis and Drosophila are high: 30%, 60%, 48% and 40%, respectively…”
J Theor Biol. 2001 Jan 7;208(1):91-107. The influence of predator--prey population dynamics on the long-term evolution of food web structure. Drossel B, Higgs PG, McKane AJ.
“Predator-prey interactions are nonlinear…” “…we find no evidence for self-organized criticality.”
Mol Biol Evol. 2001 Feb;18(2):112-9. Three divergent rDNA clusters predate the species divergence in Quercus petraea (Matt.) Liebl. and Quercus robur L. Muir G, Fleming CC, Schlotterer C. “Quercus petraea and Quercus robur are two closely related oak species that frequently hybridize. We sequenced 70 clones containing the 5.8S and ITS2 regions of ribosomal DNA (rDNA) from these two species and did not detect a species-specific difference.” “Despite a large between-rDNA-families divergence, rDNA sequences were very similar within families…”
Am J Bot. 2000 Dec;87(12):1857-1870. Molecular phylogeny and biogeography of Linanthus (Polemoniaceae). Bell CD, Patterson RW.
“Our data suggest two separate and well-supported lineages of LINANTHUS: in close association with two other genera-LEPTODACTYLON: and PHLOX: These results… do not support the traditional classification of the genus as a natural group, nor do they support the sectional classification within the genus.”
Genome Res. 2000 Nov;10(11):1719-25. Horizontal gene transfer in bacterial and archaeal complete genomes. Garcia-Vallve S, Romeu A, Palau J.
“There is growing evidence that horizontal gene transfer is a potent evolutionary force in prokaryotes, although exactly how potent is not known” “…informational genes were less likely to be transferred than operational genes.”
Behav Processes. 2000 Oct 5;51(1-3):111-134. The role of mating preferences in shaping interspecific divergence in mating signals in vertebrates. Ptacek MB.
“Pheromonal signals serve as the primary basis for species-specific mating cues in many salamander species, most mammals and even some fishes” “…the link between intraspecific preferences and interspecific divergence and speciation remains to be more fully tested.”
Science. 2000 Oct 20;290(5491):516-9. Rapid evolution of reproductive isolation in the wild: evidence from introduced salmon. Hendry et al. [Comment in: Science. 2000 Oct 20;290(5491):462-3; Science. 2001 Jan 12;291(5502):251-2; Science. 2001 Mar 9;291(5510):1853]
“…nothing is known about how quickly reproductive isolation actually evolves when new environments are first colonized.”
Mem Inst Oswaldo Cruz. 2000;95 Suppl 1:193-200. Viral diseases and human evolution. Leal Ede S, Zanotto PM.
“…all viral agents cause disease and some may in fact be considered beneficial…”
[The authors go as far as to propose the oddity that virus are a ‘driving force’ in ‘human evolution’]
Annu Rev Microbiol. 1999;53:71-102. Wolbachia pipientis: microbial manipulator of arthropod reproduction. Stouthamer R, Breeuwer JA, Hurst GD.
“W. pipientis's most common effect is a crossing incompatibility between infected males and uninfected females. Little is known about the genetics and biochemistry of these symbionts because of their fastidious requirements. The affinity of W. pipientis for the microtubules associated with the early divisions in eggs may explain some of their effects.” “W. pipientis isolates are also of interest as vectors for the modification of wild insect populations, in the improvement of parasitoid wasps in biological pest control, and as a new method for interfering with diseases caused by filarial nematodes.”
[Similarly to the previous article, the authors here go as far as to indicate that other authors have also ‘agreed’ in the oddity that Wolbachia is a ‘driving force’ in insect, crustacean, mite, and filarial nematodes ‘speciation’]
Evolution Int J Org Evolution. 2000 Aug;54(4):1337-48. Tests of pleistocene speciation in montane grasshoppers (genus Melanoplus) from the sky islands of western North America. Knowles LL.
“…relationships among some taxa remain unresolved…”
Evolution Int J Org Evolution. 2000 Aug;54(4):1303-12. Interspecific genetics of mate recognition: inheritance of female acoustic preference in Hawaiian crickets. Shaw KL.
“Female mating behavior plays a fundamental role in the divergent evolution of mate recognition systems that may lead to speciation. Despite this important role, the phenotypic and genetic bases of female mating behavior remain poorly understood.” “I examine how preference differences are inherited in hybrid crosses between these species [two species of Hawaiian crickets, Laupala kohalensis and L. paranigra]. Females expressed unimodal preference functions and were generally more attracted to pulse rates characterizing their own species. Unimodal preference functions also characterized F1 and backcross generations, with hybrid females expressing preferences for intermediate pulse rates. Pulse rate preferences segregated in the backcross generation. Mean pulse rate preference matched mean pulse rate in both parental and hybrid generations. Based on F1 hybrids and segregation patterns in backcross females…” “…changes in acoustic communication signals occurred through shifts in mean pulse rates and pulse rate preferences among populations”
Genes Genet Syst. 2000 Jun;75(3):119-30. Sex gene pool evolution and speciation: a new paradigm. Singh RS, Kulathinal RJ.
“…a paradigm shift to the study of SRR [sex and reproduction related ] genes can provide new approaches to solving some of the old problems in evolutionary biology” “…genes affecting viability versus fertility is the key…”
Bioessays. 2000 Oct;22(10):938-46. Reproductive mode and speciation: the viviparity-driven conflict hypothesis. Zeh DW, Zeh JA.
“In birds and frogs, species pairs retain the capacity to produce viable hybrids…” “We propose that reproductive mode is a critically important but previously overlooked factor in the speciation process.” “The viviparity-driven conflict hypothesis provides a parsimonious explanation…”
Heredity. 2000 Jul;85 ( Pt 1):20-9. Are flightless Galapaganus weevils older than the Galapagos Islands they inhabit? Sequeira AS, Lanteri AA, Scataglini MA, Confalonieri VA, Farrell BD.
“This estimate exceeds geological ages of the extant emerged islands, although it agrees well with molecular dating of endemic Galapagos iguanas, geckos and lizards. An apparent explanation for the disagreement between geological and molecular time-frames is… submarine seamounts (sunken islands)…”
Chromosoma. 2000 Jul;109(4):245-58. Molecular cytogenetic analyses and phylogenetic studies in the Nicotiana section Tomentosae. Lim KY, Matyasek R, Lichtenstein CP, Leitch AR.
“Here we present another approach to phylogeny, using fluorescent in situ hybridisation [GISH]” “…interesting in the context of the debate on genetically modified organisms and the escape of genes into the wild.” “It is known for N. tabacum that gene conversion has converted most 18S-5.8S-26S rDNA units of N. sylvestris origin into units of an N. tomentosiformis type. Clearly if such a phenomenon were widespread across the genome, genomic in situ hybridisation (GISH) to distinguish the S and T genomes would probably not work since conversion would tend to homogenise the genomes. The fact that GISH does work suggests a limited role for gene conversion…”
J Theor Biol. 2000 Aug 21;205(4):527-42. Rapid speciation via parallel, directional selection on regulatory genetic pathways. Johnson NA, Porter AH.
“When the phenotype is subject to parallel selection in a pair of independent populations, we find that the fitnesses of F(1)and F(2)hybrids often drop to very low values as the populations respond in genetically different and incompatible ways. The simulations support the predictions of the analytical models. Hybrid fitness reduction occurs more often as the number of loci in the pathway increases, and as the binding site interactions become more complex. Less hybrid fitness reduction is seen when the populations start with imperfect binding in the pathway. In contrast, when we constructed the phenotype without gene regulation using multiplicative rules, isomorphic to the additive phenotype commonly assumed in evolutionary models, we found no appreciable F(1)fitness reduction and only slight F(2)fitness reduction. The interaction of genetic drift and mutation, even at very high rates, did not reduce hybrid fitness at all on the time-scales we considered” “…much more empirical information is needed on the effect of allelic variability in regulatory site interactions before this role is fully understood.”
Immunogenetics. 2000 Jun;51(7):556-75. Mhc class II B gene evolution in East African cichlid fishes. Figueroa et al.
“The analysis revealed point mutations to be the most important mechanism…” “The phylogeny of the exon was incongruent with that of the flanking introns…”
Mem Inst Oswaldo Cruz. 2000 Jul-Aug;95(4):545-51. Analysis of genetic diversity of Trypanosoma cruzi: an application of riboprinting and gradient gel electrophoresis methods. Stothard et al.
“Phenetic analysis of PCR-RFLP profiles indicated that, with one or two exceptions, stocks of T. cruzi could be broadly partitioned into two groups that formally corresponded to T. cruzi I and T. cruzi II respectively.” “Whether or not these divergent types are equally transcriptionally active throughout the life cycle, remain to be assessed.”
Med Vet Entomol. 2000 Jun;14(2):149-64. Cytogenetics of the Anopheles gambiae complex in Sudan, with special reference to An. arabiensis: relationships with East and West African populations. Petrarca et al.
“In the great majority of the samples all polymorphic inversions were found to be in Hardy-Weinberg equilibrium.”
Mol Phylogenet Evol. 2000 Jun;15(3):369-80. Evolution in the high Andes: the phylogenetics of Muscisaxicola ground-tyrants. Chesser RT.
“Relationships among Muscisaxicola species were found to differ substantially from those of previous views, suggesting convergence in traditional avian taxonomic characters within the genus.”
Am J Bot. 2000 Jun;87(6):793-810. Intersectional gene flow between insular endemics of Ilex (Aquifoliaceae) on the Bonin Islands and the Ryukyu Islands. Setoguchi H, Watanabe I I.
“Intersectional hybridization and nuclear gene flow were independently observed in insular endemics of ILEX: on both sets of islands…”
Heredity. 2000 May;84 ( Pt 5):587-98. Quantitative trait loci and gene interaction: the quantitative genetics of metapopulations. Goodnight CJ.
“…when there is only additive gene action, populations can differentiate for population means, but not for residual local average effects.”
Nature. 2000 May 25;405(6785):451-4. Chromosomal evolution in Saccharomyces. Fischer et al.
“The chromosomal speciation model invokes chromosomal rearrangements as the primary cause of reproductive isolation.” “Reproductive isolation in yeast is due to post-zygotic barriers, as many species mate successfully but the hybrids are sterile” “…rearrangements have occurred between closely related species, whereas more distant ones have colinear genomes. Thus, chromosomal rearrangements are not a prerequisite for speciation in yeast and the rate of formation of translocations is not constant. These rearrangements appear to result from ectopic recombination between Ty elements or other repeated sequences.”
Proc Natl Acad Sci U S A. 2000 May 9;97(10):5313-6. The phylogeny of closely related species as revealed by the genealogy of a speciation gene, Odysseus. Ting CT, Tsaur SC, Wu CI.
“Molecular differentiation between races or closely related species is often incongruent with the reproductive divergence of the taxa of interest” “…we analyzed DNA polymorphism at the Odysseus (OdsH) locus of hybrid sterility between Drosophila mauritiana and Drosophila simulans…” “This locus thus may represent a test case…”
Genetics. 2000 Mar;154(3):1053-68. Trinucleotide repeats are clustered in regulatory genes in Saccharomyces cerevisiae. Young ET, Sloan JS, Van Riper K.
“DNA trinucleotide repeats (TNRs) are found at a higher-than-expected frequency within ORFs, and the amino acids encoded by the TNRs represent a biased set. TNRs are rarely conserved between genes with related sequences, suggesting high instability or a recent origin.” “TNRs could serve as hot spots for recombination…”
Proc R Soc Lond B Biol Sci. 2000 Feb 7;267(1440):217-23. Constraints on polyploid evolution: a test of the minority cytotype exclusion principle. Husband BC.
“Polyploid evolution is often considered a mechanism of instant speciation; yet the establishment of rare tetraploids within diploid populations may be constrained by a frequency-dependent mating disadvantage (minority cytotype exclusion principle). I tested this hypothesis…” “Seed set in tetraploids was independent of cytotype frequency. The frequency-independent effect in tetraploids reflects higher assortative mating, partly because of non-random patterns of bee visitation. Bees visited a disproportionately high number of diploid inflorescences; however, the proportion of successive flights between tetraploids increased above random expectations as the frequency of tetraploids decreased. These results provide the first experimental test of frequency-dependent fitness in diploid-polyploid mixtures…”
Nature. 2000 Feb 24;403(6772):886-9. Rapid evolution of reproductive barriers driven by sexual conflict. Gavrilets S. [Comment in: Nature. 2000 Sep 14;407(6801):149-50.]
“The positive selection for evolutionary novelty that appears to be acting on fertilization systems seems paradoxical because successful reproduction requires the close matching of female and male traits.” “Here I develop a simple mathematical model…”
Plant Mol Biol. 2000 Jan;42(1):205-24. Hybridization, introgression, and linkage evolution. Rieseberg LH, Baird SJ, Gardner KA.
“We recommend that future studies of hybrid genomes focus on natural hybrids, not only because of the paucity of data in this area, but also because of the availability of highly recombinant hybrid genotypes in hybrid zones. Of particular value will be studies of long-lived or difficult-to-propagate organisms, which previously have not been amenable to genetic study.”
Mol Phylogenet Evol. 2000 Feb;14(2):232-49. Study of the evolutionary relationships among Limonium species (Plumbaginaceae) using nuclear and cytoplasmic molecular markers. Palacios et al.
“…the remaining subsections into which section Limonium is currently divided seem to be artificial.”
TRENDS IN ECOLOGY AND EVOLUTION. 2000 Mar;15(3):104-109. Colonization and diversification: towards a phylogeographic synthesis for the Canary Islands. Juan I I, Emerson BC, Orom I I, Hewitt GM.
“Some authors have considered Canarian endemisms as relicts of Tertiary origin, but new molecular data suggest a general pattern of continental dispersion…” “Recent phylogeographic studies are revealing variants of the simple stepping-stone colonization model that seems to hold for many Hawaiian groups. Many factors can generate deviations from such a pattern.” “An understanding of island colonization and diversification can best be developed from an ecosystem level synthesis as more data for the Canarian archipelago come to hand.”
Tissue Antigens. 1999 Dec;54(6):560-4. Trans-speciation maintenance in the MHC region of a polymorphism which includes a polymorphic dinucleotide locus, and the de novo arisal of a polymorphic tetranucleotide microsatellite. Crouau-Roy B.
“Alleles and the surrounding regions of DQCAR, a dinucleotide repeat tightly linked to HLA-DQB1, were sequenced in a range of primate species including man.” “The 5' sequence displayed six alleles in the individuals studied. One of these alleles was invariably associated with substitutions in the GT repeat and absence of the CTGT repeat…” “Those carrying allele 1 were only found in man…” “…alleles in the 5' region, but from different species, are… often more similar than alleles from the same species, a phenomenon already shown for some HLA genes.” “This study provides information… of the trans-speciation maintenance of polymorphism of its surrounding sequences.”
Genome. 1999 Dec;42(6):1033-41. Broad-sense sexual selection, sex gene pool evolution, and speciation. Civetta A, Singh RS.
“This article focuses on the need for an extension of sexual selection… as an alternative to models that limit speciation to strict demographic conditions or treat it simply as an epiphenomenon…”
Anim Behav. 1999 Jul;58(1):181-184. Mate choice in divergent morphs of the gastropod mollusc Littorina saxatilis (Olivi): speciation in action? Pickles AR, Grahame J.
“We investigated mate choice in the gastropod Littorina saxatilis (Olivi) in the laboratory, using snails taken from two shores, 20 km apart.”
Gene. 1999 Sep 30;238(1):115-34. RNAs from all categories generate retrosequences that may be exapted as novel genes or regulatory elements. Brosius J.
“While the significance of middle repetitive elements had been neglected for a long time, there are again tendencies to ascribe most members of a given middle repetitive sequence family a functional role--as if the discussion of SINE (short interspersed repetitive elements) function only can occupy extreme positions” “…differences between the various classes of retrosequences concern mainly their copy numbers. Consequently, the function of SINEs should be viewed as pragmatic such as, for example, mRNA-derived retrosequences, without underestimating the impact of retroposition for generation of novel protein coding genes or parts thereof (exon shuffling by retroposition) and in particular of SINEs (and retroelements) in modulating genes and their expression.” “In addition to providing mobile regulatory elements, small RNA-derived retrosequences including SINEs can, in analogy to mRNA-derived retrosequences, also give rise to novel small RNA genes. Perhaps not representative for all SINE/master gene relationships, we gained significant knowledge by studying the small neuronal non-messenger RNAs, namely BC1 RNA in rodents and BC200 RNA in primates. BC1 is the first identified master gene generating a subclass of ID repetitive elements, and BC200 is the only known Alu element (monomeric) that was exapted as a novel small RNA encoding gene.”
Proc Natl Acad Sci U S A. 1999 Oct 12;96(21):11910-5. Pollinator preference and the evolution of floral traits in monkeyflowers (Mimulus) Schemske DW, Bradshaw HD Jr.
“A paradigm of evolutionary biology is that adaptation and reproductive isolation are caused by a nearly infinite number of mutations of individually small effect.” “Observations of F(2) hybrids produced by crossing bee-pollinated Mimulus lewisii with hummingbird-pollinated Mimulus cardinalis revealed that bees preferred large flowers low in anthocyanin and carotenoid pigments, whereas hummingbirds favored nectar-rich flowers high in anthocyanins. An allele that increases petal carotenoid concentration reduced bee visitation by 80%, whereas an allele that increases nectar production doubled hummingbird visitation.”
Curr Opin Microbiol. 1999 Oct;2(5):519-23. Gene transfer, speciation, and the evolution of bacterial genomes. Lawrence JG.
“Studies in microbial evolution have focused on the origin and vertical transmission of genetic variation within populations experiencing limited recombination. Genomic analyses have highlighted the importance of horizontal genetic transfer in shaping the composition of microbial genomes, providing novel metabolic capabilities, and catalyzing the diversification of bacterial lineages.”
J Theor Biol. 1999 Sep 7;200(1):19-37. Epigenetic inheritance, genetic assimilation and speciation. Pal C, Miklos I.
“Epigenetic inheritance systems enable the environmentally induced phenotypes to be transmitted between generations.” “…we discuss the "exploratory" behaviour of an epigenetic inheritance system on a one peak adaptive landscape. If a quantitative trait is far from the optimum, then it is advantageous to induce heritable phenotypic variation. Conversely, if the genotypes get closer to the peak, it is more favorable to canalize the phenotypic expression of the character. This process would lead to genetic assimilation. Next we show that the divergence of heritable epigenetic marks acts to reduce or to eliminate the genetic barrier between two adaptive peaks. Therefore, an epigenetic inheritance system can increase the probability of transition from one adaptive state to another.” “Remarkably, drift-induced transition is facilitated even if phenotypic variation is not heritable.”
Proc Natl Acad Sci U S A. 1999 Aug 31;96(18):10272-7. Developmental shifts and species selection in gastropods. Duda TF Jr, Palumbi SR.
“All eight species without planktonic life history phases recently and independently evolved this characteristic from ancestors with planktonic larval phases, showing that transitions in developmental mode are common in this group.” “Such results challenge the conclusion that increases in the number of nonplanktonic species relative to species with planktonic larvae over geologic time is necessarily a result of higher rates of speciation of nonplanktonic lineages…”
Science. 1999 Aug 20;285(5431):1265-7. Conservatism of ecological niches in evolutionary time. Peterson AT, Soberon J, Sanchez-Cordero V V.
“Theory predicts low niche differentiation between species over evolutionary time scales, but little empirical evidence is available.” “Reciprocal geographic predictions based on ecological niche models of sister taxon pairs of birds, mammals, and butterflies in southern Mexico indicate niche conservatism…”
Proc Natl Acad Sci U S A. 1999 Aug 3;96(16):9172-7. The signature of balancing selection: fungal mating compatibility gene evolution. May G, Shaw F, Badrane H, Vekemans X.
“A key problem in evolutionary biology has been distinguishing the contributions of current and historical processes to the maintenance of genetic variation.” “However, evidence for balancing selection and extended residence times has almost exclusively depended on identification of transspecific polymorphisms…” “The widespread geographic distribution of identical b1 alleles suggests that their association with differing A mating types is the result of recent recombination events.”
Nature. 1999 Jul 22;400(6742):354-7. On the origin of species by sympatric speciation. Dieckmann U, Doebeli M. [Comment in: Nature. 1999 Jul 22;400(6742):311-2.]
“Understanding speciation is a fundamental biological problem” “…sympatric speciation [lack of geographical isolation] has often been dismissed, partly because of theoretical difficulties. Most previous models analysing sympatric speciation concentrated on particular aspects of the problem while neglecting others. Here we present a model that integrates a novel combination of different features… [such as] assortative mating (where individuals mate preferentially with like individuals)…”
Nature. 1999 Jul 22;400(6742):351-4. Interactions among quantitative traits in the course of sympatric speciation. Kondrashov AS, Kondrashov FA. [Comment in: Nature. 1999 Jul 22;400(6742):311-2.]
“Here we use the hypergeometric phenotypic model to show that sympatric speciation is possible…”
Ann N Y Acad Sci. 1999 May 18;870:301-13. Evolution of DNA organization in hypotrichous ciliates. Prescott DM.
“…multiple, short, unique, noncoding sequences, called IESs, have been inserted into micronuclear genes. IESs are spliced out of each gene, and the gene segments, called MDSs, are ligated during conversion of the micronuclear genome to a macronuclear genome after cell mating.” “The origin of nonrandom scrambling patterns can be explained by a model of simultaneous insertion of multiple IESs into a germline gene…” “The significance of this fluidity for the life and evolution of these organisms is still obscure.”
Ann N Y Acad Sci. 1999 May 18;870:223-37. Speciation of cone snails and interspecific hyperdivergence of their venom peptides. Potential evolutionary significance of introns. Olivera et al.
“All 500 species of cone snails (Conus) are venomous predators. From a biochemical/genetic perspective, differences among Conus species may be based on the 50-200 different peptides in the venom of each species. Venom is used for prey capture as well as for interactions with predators and competitors. The venom of every species has its own distinct complement of peptides. Some of the interspecific divergence observed in venom peptides can be explained by differential expression of venom peptide superfamilies in different species and of peptide superfamily branching in various Conus lineages into pharmacologic groups with different targeting specificity. However, the striking interspecific divergence of peptide sequences is the dominant factor in the differences observed between venoms. The small venom peptides (typically 10-35 amino acids in length) are processed from larger prepropeptide precursors (ca. 100 amino acids).”
Mol Phylogenet Evol. 1999 Aug;12(3):360-85. Polyphyly and convergent morphological evolution in Commelinales and Commelinidae: evidence from rbcL sequence data. Givnish et al.
“Phylogenetic relationships of the five families of the order Commelinales remain an area of deep uncertainty in higher-level monocot systematics, despite intensive morphological and anatomical study.” “Species diversity is unrelated to the rate/amount of rbcL sequence evolution.”
Proc Natl Acad Sci U S A. 1999 Jun 22;96(13):7348-51. Mutation, recombination, and incipient speciation of bacteria in the laboratory. Vulic M, Lenski RE, Radman M.
“Mutations in the DNA mismatch repair system increase mutation and recombination. They may thereby promote the genetic divergence that underlies speciation...” “We knocked out the repair system in lines that had retained this function, and we restored function to those lines that had become defective. We then estimated recombination rates in various crosses between these repair-deficient and -proficient strains.”
Arch Virol. 1999;144(4):637-56. Evolution of herpes simplex virus type 1 under herpesviral evolutionary processes. Umene K, Sakaoka H.
“Relationships between HSV-1 genotypes and human ethnic groups can be traced by analyses of DNA polymorphisms of HSV-1 strains present in populations of various countries. A close association of an HSV-1 genotype with a particular historical human population seems probable. Such being the case, the host-linked mode is likely to be linked to diversification of HSV-1 in human populations.”
Anat Rec. 1999 Feb 15;257(1):15-31. Homeobox genes, fossils, and the origin of species. Schwartz JH.
“Ever since Darwin there has been a history of debate on the tempo and mode of evolution.” “I present a model of evolutionary change that is based on the Mendelian inheritance of mutations in regulatory genes and the fact that most nonlethal mutations arise in the recessive state. Since the new recessive allele will spread through many generations without expression until there is a critical mass of heterozygotes capable of producing homozygotes for the mutation, the novel feature thus produced will appear abruptly in the population and in more than one individual. This picture of punctuation is consistent with the fossil record, which typically fails to provide evidence of smoothly transitional states of morphological change.” “…this process does not depend on either reproductive isolation or genetic incompatibility... the species barrier between individuals is probably a matter of mate recognition.”
To be continued…
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Fernando Castro-Chavez
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posted 14. April 2004 16:42
Putting Limits on the Diversity of Life.
(Part Four. Continued... 6)
Rev Biol Trop. 1997 Jun;45(2):753-71. In search of a bacterial species definition. Moreno E.
“The bacterial species concept was examined within the framework of plant and animal associated alpha-2 proteobacteria, taking into consideration the phylogenetic, taxonomic and biological approaches as well as the microbiologists' perception. The virtue of the phylogenetic approach is that it gives an evolutionary perspective of the bacterial lineage; however the methods used possess low resolution for defining species located at the terminal branches of the phylogenetic trees. The merit of the taxonomic approach is that species are defined on the basis of multiple characteristics allowing high resolution at the terminal branches of dendograms; its disadvantage is the inaccuracy in the earlier nodes. On an individual level, the qualitative biological characteristics used for the definition of species frequently reveal shortcomings…” “…when considered together with the phylogenetic and taxonomic approaches, important uncertainties are discovered: these must be weighed if a practical definition of bacterial species is conceived. The microbiologists' perception is the criterion expressed by a group of sponsors who, based on scientific and practical grounds, propose a new bacterial species. The success of this new proposal is measured by its widespread acceptance and its permanence” “…the inherence is vertically transmitted as a result of binary fission and clonal expansion. This may be the case of some animal cell associated bacteria in which recombination appears to be precluded or exceptional. In the second case adaptive changes occurring within an individual can be horizontally transferred to many or all group members. This seems to be the condition of many intestinal and plant associated bacteria.” “…in clonal bacteria will depend almost exclusively on mutation and internal genetic rearrangement processes…” “…in reticulate bacteria will depend not only on these processes but in their genetic interactions with other bacterial strains. This uncertainty… is at the same time one of the key factors in defining a bacterial species.”
Antonie Van Leeuwenhoek. 1997 Jul;72(1):63-76. Eukaryotic molecular biodiversity: systematic approaches for the assessment of symbiotic associations. Hackstein JH.
“ 'Biodiversity' addresses the wealth of species that constitute the biosphere. Notwithstanding that they have been regarded as mental constructs in the past, species are really existing entities that form and disappear…” “Molecular techniques allow…” “…incredible diversity of protists: their importance for the global conversion of biomass and energy had been greatly underestimated until recently.” “Therefore, new concepts are required to calculate global biodiversity. Systematic approaches that evaluate small, complex biotopes exhaustively, or that calculate the number of symbionts or parasites on the basis of their potential hosts have already led to a substantial revision of earlier estimations. Here, an evaluation of potential animal hosts for methanogenic archaea and intestinal protists is described that reveals the importance of host taxonomy for the assessments. If molecular techniques can confirm the presumed specificity of symbiotic and parasitic associations a substantial revision of the current assumptions about the biodiversity of such organisms will be necessary.”
Antonie Van Leeuwenhoek. 1998 Jan;73(1):25-33. Santa Rosalia revisited: why are there so many species of bacteria? Dykhuizen DE.
“The diversity of bacteria in the world is very poorly known. Usually less than one percent of the bacteria from natural communities can be grown in the laboratory. This has caused us to underestimate bacterial diversity and biased our view of bacterial communities. The tools are now available to estimate the number of bacterial species in a community and to estimate the difference between communities. Using what data are available, I have estimated that thirty grams of forest soil contains over half a million species. The species difference between related communities suggests that the number of species of bacteria may be more than a thousand million.”
[Sub-speciation is the real variation within species. Sub-speciation is confounded with ‘speciation’, which is the evolutionist speculation of the fictitious ‘jumping’ of one species to be transformed into another species. The best test is the original definition of kind, that can be applied to the word ‘Species’: “Fertile parents producing fertile offspring”, that implies the need of the reproductive ‘fertility test’ also for the offspring. ‘Evolution’ tries to confound the unlearned with tricky and weak definitions of ‘species’ to walk around and aside from the simple and original truth present in the word ‘kind’]
Proc R Soc Lond B Biol Sci. 1998 Jan 7;265(1390):25-32. Spatially induced speciation prevents extinction: the evolution of dispersal distance in oscillatory predator-prey models. Savill NJ, Hogeweg P.
“…if the populations reproduce sexually, local gene flow can inhibit the evolution of increasing dispersal distances, and hence the spatial patterns are not lost. Speciation and coexistence can also occur in the sexually reproducing species.”
[Same comment as in the previous Abstract]
Proc Natl Acad Sci U S A. 1997 Jul 22;94(15):7768-75. Genetics and the origin of bird species. Grant PR, Grant BR.
“Ideas about the genetics of speciation in general trace back to Dobzhansky who worked with Drosophila. These ideas are an insufficient guide for reconstructing speciation in birds…” “…the genetic basis to the origin of bird species is to be sought in the inheritance of adult traits…” “The genetic basis of the origin of postmating isolating factors affecting the early development of embryos (viability) and reproductive physiology (sterility) is almost completely unknown. Bird speciation is facilitated by small population size, involves few genetic changes, and occurs relatively rapidly.”
[Same comment as in the earlier Abstract. Here ‘sub-speciation’ is been sold as ‘speciation’ in order to keep the ‘double-talk’, the ‘weak and confusing terminologies’, and the illusory concepts of ‘evolution’, but the full text, as demonstrated before, presents a different picture in which different ‘species’ of Galapagos finches interbreed and produce fertile offspring, being then, not different ‘species’ but the same ‘species’. The error being in the easy and superficial morphological classification done by Darwin and by others, instead of being based on the ancient definition of ‘kind’ previously discussed (“fertile progenitors yielding fertile little ones that in its time will breed producing fertile offspring”). ‘Species’ cannot only be defined morphologically, as dogs, cows and humans demonstrate]
Mol Phylogenet Evol. 1997 Apr;7(2):158-72. Evolutionary age of the Galapagos iguanas predates the age of the present Galapagos islands. Rassmann K.
“The results strengthen the hypothesis that extended speciation times in the Galapagos are possible and provide an estimate of the minimum time inhabited islands of the archipelago may have existed.”
[Those iguanas also interbreed, being then the same species; so, the ‘dating’ here and in every other ‘evolutionary estimate’ is totally useless]
Proc R Soc Lond B Biol Sci. 1997 Mar 22;264(1380):355-60. Genetic distinctiveness of a village population of house mice: relevance to speciation and chromosomal evolution. Fraguedakis-Tsolis S, Hauffe HC, Searle JB.
“It has frequently been proposed that genetic drift/founder events are of importance in the fixation of chromosomal rearrangements; this study provides the first direct evidence for their occurrence in alpine mouse populations.”
[Did they did fertility experiments to see if both kinds of mice interbreed and have fertile offspring? No]
J Theor Biol. 1995 Dec 7;177(3):237-45. A genetical theory of species selection. Rice SH.
“So long as we are careful in defining "species", the logic of species selection is sound. This does not mean, however, that this process can influence evolutionary dynamics under realistic conditions. The principal challenge to the efficacy of species selection as an evolutionary mechanism is the idea that selection between individuals within species will be so much more efficient as to swamp out any effects of selection between species.” “Quantitative characters, such as body size, generally change too readily for species selection to be relevant….” “Complex characters, however, may be good candidates to be influenced by species selection. The interaction of selection within and between species can be subtle, with individual selection looking, from the standpoint of a species, very much like development of an individual.”
[‘Species’ defined as a Kind, as previously declared]
Philos Trans R Soc Lond B Biol Sci. 1996 Jun 29;351(1341):753-64. Small mammal differentiation on islands. Berry RJ.
“The reason for the distinctiveness of small mammals on islands has traditionally attracted some imaginative story-telling, usually invoking isolation (as a relict) followed by adaptation and/or random genetic changes.” “Probably most post-colonization change is adaptive, although possibly limited in extent both by the initial paucity of variation and by the conservative effect of intragenomic interactions” “…the 'founder effect' or principle commonly invoked in discussions about evolution on islands involves a founder 'event', followed by founder 'selection'. Island differentiation is not necessarily a precursor to speciation…” “Notwithstanding, island forms provide a valuable 'laboratory' for testing new genetic combinations, a small proportion of which may prove evolutionarily exciting. Only more empirical studies will uncover their evolutionary importance.”
J Mol Evol. 1997;44 Suppl 1:S57-64. Genome plasticity as a paradigm of eubacteria evolution. Watanabe H, Mori H, Itoh T, Gojobori T.
“…We found that dynamic rearrangements have so frequently occurred in eubacterial genomes as to break operon structures…” “Interestingly, in such eubacterial genomes of high plasticity, we could find several highly conservative regions with the longest conserved region comprising the S10, spc, and alpha operons.”
Development. 1999 Feb;126(5):851-9. Fossils, molecules and embryos: new perspectives on the Cambrian explosion. Valentine JW, Jablonski D, Erwin DH.
“Various attempts to date those branchings by using molecular clocks have disagreed widely” “…timing of the evolution of the developmental systems of living metazoan body plans is still uncertain…”
J Biochem (Tokyo). 1999 Apr;125(4):649-57. Halobacterial rhodopsins. Mukohata et al.
“The four kinds of rhodopsin in each strain are assumed, on the basis of their genera-specific distributions…” “The original rhodopsin ancestor is speculated to be closest to the proton pump (bacteriorhodopsin).”
Mol Biol Evol. 1996 Feb;13(2):397-406. Positive selection and sequence rearrangements generate extensive polymorphism in the gamete recognition protein bindin. Metz EC, Palumbi SR.
“Bindin is a gamete recognition protein of sea urchins that mediates species-specific attachment of sperm to an egg-surface receptor during fertilization. Sequences of bindin from closely related urchins show fixed species-specific differences. Within species, highly polymorphic bindin alleles result from point substitution, insertion/deletion, and recombination.” “These results show that polymorphism in mate recognition loci… can arise within natural populations.”
J Mol Biol. 1999 Jan 8;285(1):163-74. Evolution of the archaeal rhodopsins: evolution rate changes by gene duplication and functional differentiation. Ihara et al.
“By calculating the branch lengths between the gene duplication point and each halophilic archaea speciation point, we could speculate…”
Proc R Soc Lond B Biol Sci. 1999 Apr 7;266(1420):677-85. Molecular phylogenetic evidence for the evolution of specialization in anemonefishes. Elliott JK, Lougheed SC, Bateman B, McPhee LK, Boag PT.
“The molecular phylogeny differs from the tree based on morphological data…” “Further phylogenetic studies of additional anemonefish species are required to substantiate this hypothesis.”
Immunogenetics. 1998;47(2):115-23. Characterization of chimpanzee TCRV gene polymorphism: how old are human TCRV alleles? Jaeger EE, Bontrop RE, Parham P, Wickings EJ, Kadwell M, Lanchbury JS.
“The functional relevance of the majority of human T-cell receptor A and B [TCRA and B] variable region gene polymorphisms is controversial.” “We investigated at the DNA level whether 15 human TCRA and B polymorphisms exist in contemporary chimpanzee populations. Polymorphisms consisted of variable region replacements, a recombination signal sequence base change, and silent mutations. With one exception, none of these human TCR polymorphisms were observed in contemporary chimpanzees.” “Chimpanzee TCRAV and BV regions were however polymorphic for variation so far not observed in human groups” “…TCRA and B polymorphisms have not been maintained by selection to the same degree as post | | |
