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Topic: Phillip L. Engle: New Evolutionary Theory: The End of Ideology
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peter borger
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posted 05. May 2004 10:17
RB,
Grishok and coworkers showed that the introduction of dsRNA triggers sequence specific genetic interference (RNAi) that is transmitted to the offspring, and they provided evidence for germ line transmission of an extragenic sequence specific silencing factor, mediated by a preexisting genomic mechanism implicating rde-1 and rde-4. (Science 2000, 287:2494-7)
Peebee
[ 05. May 2004, 10:20: Message edited by: peter borger ]
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nosivad
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posted 05. May 2004 10:31
The key words here as I understand it are "preexisting genomic mechanism". As far as I can ascertain, the entire evolutionary sequence of events has been predetermined and emergent with little or no participation on the part of the environment. In that respect evolution clearly mirrors ontogeny where there is little if any role for the environment. I really don't expect anyone to buy this idea as it is admittedly somewhat radical. However, at present I see no other conceivable explanation. Accordingly, I present it without apology.
[ 05. May 2004, 10:35: Message edited by: nosivad ]
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RB
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posted 05. May 2004 10:58
Peter,
I use RNAi, the RNAi triggers the reaction (just as a poison triggers a reaction).
The reaction makes it into the next generation (and sometimes two generations), but stops. this is not a permanent change. you need the dsRNA, the RNP particles simply persist cytoplasmically. Germ line does not mean genomic. Do you think that before this scientist didn't know that cytoplasm was trasferred to the next generation. Where does the sequence specificity come from? The dsRNA. RNAi effects are passed down from cell generation to cell generation for a short while. C. elegans, being limited in cell division and quickly developing, affords the oportunity for the effect to make it into the next generation of organisms, because the germ cell cytoplasm (amazingly even the sperm) still contains enough of the stable dsRNP effectors to silence gene expression. Once that is gone, no more effect.
This is off topic and not worthy of a separate thread, so I'll leave it here.
[ 05. May 2004, 11:01: Message edited by: RB ]
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nosivad
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posted 05. May 2004 16:04
Speaking of long lasting RNA effects, several years ago I inadvertantly crossed two frogs (Rana pipiens) each heterozygous for albinism. This was not at all obvious during early tadpole development as all the progeny were heavily pigmented. As they approached metamorphosis rougly 1/4 of them were noticeably lighter and became frogs which were yellow, with pink spots, where black spots would normally be. The pink was due to hemoglobin showing through an otherwise pigmentless skin. The yellow chromatophores in combination with Tyndall blue (due to light scattering) produce the green color of the adult frog. I had earlier observed a sky-blue frog (Hyla species) which was probably a mutant unable to produce the yellow pigment. The persistent melanin which ultimately disappeared was probably due only to the messenger RNA which had been produced in the oocyte prior to fertilization. The normal allele of the oocyte deficient gene in amphibians is also a gene producing a product which acts not at the time it is produced in the oocyte but later at the onset of gastrulation. Anyhow, if Lamarckian inheritance is becoming respectable, I want to know about it so I can abandon some of my heretical notions. At present I wouldn't give a nickle for either Darwinism or Lamarckism, at least in Eukaryotes.
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Rex Kerr
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posted 05. May 2004 21:26
nosviad wrote:
quote:
It is precisely the lack of a continuum that makes the recognition of species and genera unmistakable. Your assertion is classic propagaganda, designed to promote darwinian gradualism. One starts with an assertion that is without foundation and then proceeds to draw all sorts of conclusions from it.
All right, then, let's look at foundations. Here's a bush rat, Rattus fuscipes:
And here's a house mouse, Mus musculus:
And here's a Irish wolfhound, Canus familiaris:
And here's a Miniature dachshund, Canus familiaris:
We can't tell the difference between species-level differences and genus-level differences on the basis of breeding. We place rats and mice in separate genera--mightn't we also place dogs in separate genera if we didn't realize they could interbreed and we killed off all the intermediate sizes of dogs? Yes, there are lots of rules of thumb one can use, but they're anything but crystal clear.
And what is the deal with "sub-genus" classification if the distinction between species and genus is so clear?
And what about cases where people argue about whether an animal deserves its own genus or not, e.g. the
Northern Gannet?
Please provide some foundation for your assertion that the distinction between species and genus is unmistakeable.
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nosivad
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posted 06. May 2004 07:49
Anyone with any knowledge of taxonomy knows that external appearance has little to do with taxonomic placement. The characters that unite all dog breeds with the ancestral wolf are skeletal, dental and physiological. They have nothing to do with appearance whatsoever. This is also true in the plant kingdom. The features on which the Linnaean system securely rests are meristic, perfectly defined invariant features which by there very nature cannot have intermediate or variable states. If they did have, the entire taxonomic structure would be a shambles, which it most certainly is not. I find it amazing that you would erect the pathetic case of the dog breeds, the very example which has proven experimentally beyond any doubt that the Darwinian scheme is dead wrong. Like it or not, the vast majority of extant species are fundamentally immutable. To think otherwise is no longer acceptable, at least to this investigator.
"A rose is a rose is a rose"
Gertrude Stein
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peter borger
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posted 06. May 2004 07:53
RB, your conjecture that RNAi behaves like a poison that is diluted generation after genertaion is (of course) oversimplification of an intricate, not well understood preexisting molecular mechanism. RNAi involves several genomic elements that convey the effect (Grishok, Science 2000). Dependent on the expression of such elemenst, in particular the RNAi effect can be expected in the offspring.
Grishok et al:
...we injected pos-1 dsRNA into rde-1 (+); rde-2 (-) animals and then crossed these to generate rde-1 (-); rde-2 (+) F1 progeny. rde-1 (+) activity in the injected animals was sufficient for F1 interference even when the injected animals were homozygous for rde-2 or mut-7 mutations (Fig. 3B); however, it was not sufficient when the injected animals were homozygous for the rde-4 mutation (Fig. 3B). Thus, rde-1 can act independently of rde-2 and mut-7 in the injected animal, but rde-1 and rde-4 must function together. These findings indicate that rde-1 and rde-4 function in the formation of the inherited interfering agent, whereas rde-2 and mut-7 function at a later step.
The funny thing is that the elements are genetic redundancies:
"The rde-1 and rde-4 mutations appear to be simple loss-of- function mutations and do not exhibit overt phenotypes, except for a nearly complete absence of interference in response to dsRNA".
in: H. Tabara, et al., Cell 99, 123 (1999)
peebee
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nosivad
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posted 06. May 2004 08:15
This post was absolutely unacceptable at Brainstorms. We will not tolerate ad hom attacks.
Additionally, discussions about identities are strictly forbidden. Davison is completely wrong when he asserts that the Darwinians remain anonymous because they are secretly insecure.
My guess is that when people use pseudonymns, they do so out of internet convention, where it is rare to use actual names. Most know that they are not completely anonymous.
I could turn Davison's argument around on the Darwin-dissenters and say that the reason they use their actual names is that they are trying to make a name for themselves, trying to be revolutionaries. Trying to get their names associated with the defeat of Darwinism. Of course, this is just another ad hom.
Let's stop.
[ 06. May 2004, 09:06: Message edited by: Moderator ]
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RB
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posted 06. May 2004 09:02
Peter, without the dsRNA, which is either produced by the genome or inserted by the experimentor, how does the gene silencing work.
the poison analogy is simple yes, but then how to poisons work? through the cell, through interactions with the cell.
Of course the RNAi mechanism is mediated thorugh cellular proteins, the dsRNA does not have enzymatic activity.
I have no idea how you are making a connection to larmark with RNAi. RNAi in no way destroys the evil darwinian empire.
To Davison,
you want to know who I am, ask Paul Nelson who "outed me" a year or more ago. I surely wasn't hiding my ID from him. In fact, most of us anti-IDists have been outed by maniacal ID zealots who save our posts from years ago to forensically analyze. Hell if we gave you our IDs to start with, where would the fun be in figureing out who we are.
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peter borger
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posted 06. May 2004 09:31
Connection with Lamarck:
Heritable RNAi mediated chromatin variations may alter the frequency and distribution of classical mutations and meiotic recombination. Therefore, inherited epigenetic changes in the structure of chromatin can influence evolution as well as cause a type of "Lamarckian" inheritance.
(For more connections: do a pubmed search for Jablonka et al)
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peter borger
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posted 06. May 2004 10:40
I had a couple of minutes left, and have read a bit into this thread. Very interesting, again, I have to say.
Rex conjecture of random walk (Gould´s drunk reeling-evolutionary-analogy) has recently been demonstrated to be dead wrong by nobody else than our darwinian friend......Richard Lenski.
His more than 15 years lasting evolutionary experiment with E coli (20.000 generations) demonstrated that evolution is repeating itself over and over and thus evolution does not do random walks.
He showed that:
1) Evolutionary changes arise fast (within the first 2000 generations) and are at the level of reproduction rate (this is of course due to reshuffling of the genome, and loss of DNA elements, and affect gene expression), and after that only minor changes appear,
2) Due to loss of genetic elemenst the organism acquires a reproductive advantage,
3) Evolutionary lines that are effectively 40.000 generations appart arrive at exactly the same gene-regulatory phenotypes. Of the >4000 genes, the same 59 genes are involved and the direction of expression (up or down) for each gene was exactly the same.
4) He beliefs that the two evolutionary lines are seperate species (but only according his definition).
Apparently evolution can repeat itself and the elements that determine the course are pre-specified by E.coli´s proteogenome.
Thanks Lenski, for clearing that up,
peebee
[ 06. May 2004, 12:52: Message edited by: peter borger ]
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nosivad
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posted 06. May 2004 11:46
I DO want my name associated with the defeat of Darwinism just as I want the same for Grasse, Berg, Broom, Bateson, Goldschmidt, Schindewolf and the many others who have so effectively exposed its complete failure as a testable hypothesis. It is precisely because we remain unrecognized that Darwinism has prevailed. There is nothing ad hominem about my position whatsoever. Mine is a position born of conviction based on incontravertible facts, none of which can be reconciled with the Darwinian position. I also detect a double standard being applied here. It was perfectly acceptable to allow Gordon to describe me as incompetent and to allow that ad hominem to stand even after I asked for its removal. I have also had my honesty questioned as the moderater is well aware. That too has remained for perpetuity. Pim was allowed to completely misrepresent Schindewolf and, when I complained, the thread was closed ostensibly because of a lack of civility. There is nothing uncivil about clarifying the real position of a scholar of Schindewolf's stature. I am inclined to agree with David Raup when he was interviewed about the Creation/ Evolution debate -
"On the creation-evolution debate, I foresee continued conflict. Both sides will continue to lie, cheat and steal in order to make their points"
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Rex Kerr
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posted 06. May 2004 12:57
Peter, I'm unfamiliar with Lenski's work. Can you supply a reference please? I am familiar with work being done by someone locally and the results I've seen disagree with your characterization.
Also, you may wish to know that I have worked with C. elegans and my colleagues and I have never found an RNAi phenotype that persists more than one generation.
To nosviad: I am aware that showing pictures of animals is a bit misleading as taxonomy is based on more than that. However, the dogs I've shown have vast differences in size and notable differences in the lengths of various bones. I imagine they're fairly similar dentally, and I'm not sure which aspects of physiology you care to look at. But rats and mice have quite similar physiology, dentistry, and skeletal structure. I am much less confident than you that dogs would be correctly classified as variants of one species while a bush rat and house mouse would be classified as distinct genera.
In any case, your claims seem to exaggerate the reliability of classification. What, pray tell, is a subgenus? And how, if the distinction is so clear, can there be controversy over whether a species belongs in one genus or its own? The Gannet was just the easiest to find on Google--I've certainly heard of other such cases.
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charlie d.
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posted 06. May 2004 13:15
Peter:
I am still missing the part where you explain how the RNAi soma-to-germline process works. Even assuming that transcriptional epigenetic regulation by RNAi (as opposed to the conventional post-transcriptional mechanisms) are more widespread than they currently seem (rather than an oddity), the whole mechanism would still look like just another genomically-encoded epigenetic control mechanism. I understand you can artificially feed dsRNA to elegans, but in nature siRNAs are encoded by genes, processed by gene-encoded factors, and act on gene expression. While RNAi systems, like many genetic programs, respond to the environment according to pre-existing information, I don't see any new information flowing from the environment to the germline.
So, I still fail to see any actual evidence of a "lamarckian" process at work, even using the commonly over-abused and over-extended meaning of the term, let alone any sign that (neo)darwinian evolution is "as dead as a dodo" (whose extinction, btw, a lamarckian mechanism may well have prevented).
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nosivad
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posted 06. May 2004 15:57
Kerr or any other proponents of the Darwinian gradualist position.
I'm afraid your arguments are falling on deaf ears. I long ago abandoned every aspect of both the Darwinian and Lamarckian models on the grounds that they both have failed countless experimental trials. In addition, my experience has taught me that I am quite unable to communicate my convictions to either the Darwinian or the Fundamentalist camps. They are each, as near as I can determine, simply ideologically, and perhaps genetically, unable to accept any position other than their own. I am convinced that our attitudes concerning our origins are genetically influenced just as has already been demonstrated to be the case for how we feel about the death penalty, abortion, liberal versus conservative politics, respect for authority and belief in a Supreme Being. Just as I now believe that evolution, like ontogeny, has been a prescribed phenomenon, so apparently is also our intellectual attitude toward how it has occurred. Indeed, some actually believe evolution is going on all around us, a position which I see as without foundation. We may be, as William Wright's provocative title suggests, - "Born That Way". If that should prove to be the case, we are all wasting our time in discussing the matter. Nevertheless -
"If you tell the truth, you are certain, sooner or later, to be found out".
Oscar Wilde
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