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Author
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Topic: Semi-Meiosis as an Evolutionary Mechanism
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Christopher D. Beling
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Member # 723
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posted 04. May 2006 11:26
Intelligent Design Theory (IDT) is presently largely based on the observation of specified complexity in nature (i.e. genetic -information) and the fact that natural selection and random mutation alone cannot produce it.
Over the last few years here at iscid evolutionary biologist Prof. John Davison has in 2003, 2004 and2006 pointed out that there are other observations apart from specified complexity that should also lead one to accept some form of IDT. Professor Davison has given very strong evidence for a Prescribed Evolutionary Hypothesis (PEH) that sees evolution (phylogeny) as having taken place "in a manner similar to that of ontogeny by the derepression of preformed genomic information which was expressed through release from latency (derepression) by the restructuring of existing chromosomal information (position effects)". That is evolution is pre-programmed (from downloaded bio-information (CSI) at time(s) in the past). He has pointed out this theory is largely not his own, but is based on the work of many distinguished scientists of the past such as Bateson, Berg, Broom, Goldschmidt, Grasse and Schindewolf that have all held to some such view. The scientific evidence comes from multiple fields such as paleontology, embryology and genetics and is particularly convincing since these multiple interlocking evidences form the kind of coherent picture that one would expect of a good theory. However, if the PEH is to form the time evolving part of a comprehensive IDT then it should also explain the sharp transitions between species and long periods of "stasis" as seen in the fossil record. In his 1984 paper [ J. Theor. Biol. 111 (1984), 725-735] Semi-Meiosis as an Evolutionary Mechanism Professor Davison shows how these jumps find a rather natural explanation in terms of chromosomal rearangements that occur at the first stage of meiosis in the females of the species. With no second stage of meiosis, and without the need for a mating partner, females give birth directly to the new species.
I would like to open up this thread to discuss the SMH (Semi-Meiotic Hypothesis) and the possible means by which semi-meiotic speciation could be triggered. In doing so I hope to make the SMH more widely known and understood. If in the process technical details are required it may be that we can call upon Professor Davison to enlighten and help us.
[ 04. May 2006, 12:26: Message edited by: Christopher D. Beling ]
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John A. Davison
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posted 05. May 2006 01:46
Chris
Thank you very much for introducing my 84 paper in the Journal Of Theoretical Biology. For some reason I am unable to bring it up. It is probably a glitch somewhere. In any event I will be happy to respond to any questions that it may raise.
Thanks again
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peter borger
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Member # 722
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posted 05. May 2006 05:40
The recombination events leading to new chromosomes, as proposed by Davison's SMH, must have been non-random instant events. As such they must have been mediated by genetic elements, of which we must still be able to find them back in the genomes of all organisms.
In bacteria these elements are known as IS (insertion sequence) elements, where they act to rapidly induce adaptive phenotypes. In plants the elements are known as transposons. In animals biologists refer to these elements as HERVs and ALUs, which are considered to be remnants of viruses that invaded the genome in ancient times (a view without scientific support, however).
HERVs are usually inactive but increase their activity during meiose, i.e. they start to duplicate and transpose. They still have the ability to induce recombinations and contribute to chromosomal rearrangement. They qualify as genetic redundancy, as their inactivation does not directly affect fitness. The control over their non-random transposition has probably been lost and has become more or less random (although this is still a matter of debate). Over longer time periods they may have a detrimental effect as they may degenerate original information of genomes that ensured longevity of the organism (for instance several HERVs have moved into the human GULO gene).
peebee
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John A. Davison
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posted 05. May 2006 10:29
Evolution in reverse has already been achieved by simply scrambling and recombining yeast chromosomes. I predict that, when we can really control chromosome restructuring, we will be able to reproduce our own ancestors under controlled conditions.
I still believe that Neanderthal was our immediate ancestor simply because there was no other candidate around at the time we appeared about 100,000 years ago, the youngest mammal on this planet and probably the last one ever to appear. Of course that is just me so don't take it seriously. One thing is for sure, we weren't produced de novo.
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John A. Davison
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posted 05. May 2006 10:36
When I click on my 84 paper, nothing happens. Are others having the same problem?
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Bruce Fast
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Member # 924
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posted 05. May 2006 17:46
The link to your paper is working fine for me.
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Christopher D. Beling
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Member # 723
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posted 05. May 2006 19:28
John, Do you have a pdf reader on your computer? It is a pdf file
As a comment, isn't 100,000 years too long ago for modern man? I thought the transition from Neanderthal to Cro-Magnon (Homo Sapiens Sapiens) was around 35,000 years ago (at least according to present anthropology)? Also what do you make of these studies that say that Neanderthal mDNA is significantly different from ours so that there could be no genetic link? Incidentally I have also wondered about this transition, because there seems to be a complete absence of modern human remains up until 35,000 years and would expect to see at least something. Chris
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Christopher D. Beling
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posted 05. May 2006 19:55
Hi P.B. - your post is most interesting. However, biology is not my primary discipline and so I wonder if I could ask some questions to clarify. [There may be others like me?]
The SMH requires restructuring of the chromosomes - either the addition of a new type (e.g by inversion), or perhaps the joining together of chromosomes to make a new type. You are saying that this is likely true and caused by "non random" action caused by "genetic elements".
(i) Are these "genetic elements" genes or sub-genes (domains)? What exactly are they in terms of DNA? Do they have any stand-alone function?
(ii) Some strong candidates for "genetic elements" are IS (bacteria), Transposons (plants) and ALUs and HERVS (animal)?
(iii) Are these "genetic elements" what some call "jumping genes" - i.e. they kind of jump around the chromosomes (inter and intra) either doing positive things to genes (or perhaps negative)?
(iv) How do these "genetic elements" do their work - do they go insert into genes or between them?
(iv) Do you believe in the "non-random" behavior for the genetic elements - i.e. that they behave deterministically (i.e are programmed to behave in a certain way). If so what could have "triggered" them to have switched into a different mode of action at the time of SMH speciation?
Thanks for your patience. Chris
[ 05. May 2006, 19:57: Message edited by: Christopher D. Beling ]
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Bruce Fast
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posted 06. May 2006 00:42
Christopher D. Beling: "Incidentally I have also wondered about this transition, because there seems to be a complete absence of modern human remains up until 35,000 years and would expect to see at least something."
Could you please elaborate and clarify. Are you saying that there are no modern human remains at 40,000 years ago, or at 25,000 years ago? What kind of remains are there that date to 40,000 years, 50,000 years?
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John A. Davison
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posted 06. May 2006 00:52
The exact date of the appearance of Homo sapiens is of no conseunce in any event. The important thing is that he is apparetly the last mammal speces to ever appear on this planet.
I also fail to see what that has to do with my paper.
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peter borger
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posted 06. May 2006 03:32
With respect to neanderthaler mtDNA.
1) mtDNA mutates non-randomly
2) if we compare mtDNA of the great apes, the neanderthaler and (ancient) humans we observe that they all must have had a common ancestor around 150 thousand years ago.
3) DNA is highly unstable. Nucleotides degrade following chemical rules and the retrieved ancient sequences may simply reflect patterns of non-random decay.
peebee
[ 08. May 2006, 05:51: Message edited by: peter borger ]
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peter borger
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posted 06. May 2006 04:45
Chris,
The genetic elements could be the elements which are known as IS (bacteria), transposons (plants) and HERVs and Alus(mammals).
The reason I believe they contribute(d) to an rapid evolutionary process is because they still are able to induce variability in genomes. Their location in the genome affects the expression of genes and gene expression is what is observed in Darwinian evolution (which is merely variation). It is also what sets chimpanzees apart from human (gene expression pattern).
Richard Lenski and others showed in E.coli that translocation of IS elements was the only event required for phenotypic adaptations (they called it fitness increase, which is nothing but a reproductive advantage).
Barbara McClintock argued that transposons are inducing adaptive phenotypes and also the result of transposition of preexisting genetic elements (in particular during periods of stress) that may give adaptive phenotypes (Her ideas were opposed by the establishment for 30 years, then she was proven right and received the Nobel price).
HERVs and ALUs are regarded selfish elements by the establishment; remnants of viruses. They have the ability to translocate (like transposons in plants) leaving copies behind. To this end they specify two enzymes which are also used by many RNA viruses to make copies (RNA-->DNA) and then invade the genome. This has evo's prompted to classify them as (ancient, degenerate) viruses. It is, of course, the other way around: HERVs can easily pick up genes and acquire the ability to leave the genome as a virus (this is the view that everything has been created and is currently deteriorating, not evolving). My view is supported by the socalled RNA-virus paradox, which shows that all known RNA viruses have a common ancestor around 24 thousand years BP (of course this is the evolutionist's account, as it is more likely that viruses can recombine in the genome quite frequently and have an independent origin. For instance, HIV and SIV, which are currently though to have a common ancestor could as well be the result of two independent non-random mutational events in seperate genomes.)
When HERV transpose they leave an identical copy (which by the way explains why organismal change is irreversible; Davison's teleology) and this means that palindromes or repetitive sequences occur in the genome (the human genome makes up 20% of them). Palindromes but also repetitive sequences are known for their ability to form hot spots for recombination events. If we assume that the original HERV translocations were controlled we can begin to understand the mechanisms of instant evolution. It also explains why we find many HERVs in the exact same location of the genomes of chimps and humans.
Humans have however a few distinctly different HERV in comparison with chimps, which, I propose, have been added to induce the tremendous amount of variation as the creator anticipated to populate this planet with billions of poeple: HERVs provide a literally infinite number of combinations to differential gene expression. Intelligent, isn't it? Of course, as all HERVs are redundant genetic elements they will whither away rapidly and also the control system of redundant systems are not subject to selection.
With this we have just found ourselves a new biological law.
SPECIATION IS A REDUNDANT TRAIT
GUToB explains it all.
peebee
[ 06. May 2006, 04:58: Message edited by: peter borger ]
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John A. Davison
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posted 06. May 2006 06:51
The creator also made it possible for the earth to be populated with several billion chickens, our greatest potential enemy.
As for evolution going on, I want to see a single documented example of a known species, fossil or extant, which has produced another known species. What we see is not "evolution in action" as so many believe but the products of a past evolution no longer in progress and that has not been in progress for a very long time. When it did take place it was entirely saltational with no gradual transitional forms whatsoever.
Also prokaryotes are not models for eukaryyote evolution. They are dead ends too.
"A past evolution is undeniable. A present evolution is undemonstrable.
John A. Davison
As for my paper, why can't it simply be presented in its enirely right here as is the usual practice?
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peter borger
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posted 06. May 2006 09:41
John, billions of people would need billions of chickens to eat. (Don't get carried away by the media reports on bird flue, or chicken pox, or whatever)
peebee
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Christopher D. Beling
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posted 06. May 2006 10:33
Dear John when you say "as for my paper, why can't it simply be presented in its entirety right here as is the usual practice?" I find myself wanting to help but not knowing how to?
Is it that you still cannot read the link? I thought that most papers were presented here in pdf format. Can anyone help out here? Is anyone else having difficulty opening the paper?
We do indeed need to focus in on your paper - I would thus like to encourage all here to take time to read your 1984 Semi-Meiosis paper (click here) and to make comment on specifics.
Chris
[ 06. May 2006, 11:01: Message edited by: Christopher D. Beling ]
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