tag:blogger.com,1999:blog-37148773.post1885609883518644389..comments2024-03-27T14:50:47.345-04:00Comments on <center>Sandwalk</center>: Calling All Adaptationists (Again)Larry Moranhttp://www.blogger.com/profile/05756598746605455848noreply@blogger.comBlogger69125tag:blogger.com,1999:blog-37148773.post-61811396832942887942007-09-25T09:40:00.000-04:002007-09-25T09:40:00.000-04:00I ask, please, for the third time: Give me an exam...<I>I ask, please, for the third time: Give me an example of a SIMPLE polygenic adaptation that has been shaped by selection.<BR/>I think my objection of the cichlid paper was clear enough. I am noit unfarily rejecting the case: Ia m questioning the assumption the oral jaw apparatus can be considered a metric trait o which the ACTUAL metric ttraits that compose it make and always "postive" contribution: only if they do this can they apply the test of selection they consider as "evidence".<BR/>I guess Sven and Windy are simply not smart enough to understand this objection. It already flew right past their heads once.</I><BR/><BR/>No, we noticed you pulled "metric trait" right out of your ass. What you originally said was:<BR/><BR/><I>I'm more interested in the case where directional selection is supposed to accumulate genes with small phenotypic effects, to thus produce an important adaptive difference between sibling species.</I><BR/><BR/>No mention of a single metric trait. But if you want a metric trait responding to selection, what's wrong with the entire fucking history of agriculture?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-30413250597469271552007-09-24T14:27:00.000-04:002007-09-24T14:27:00.000-04:00"Natural homeotic transformations in evolution are..."Natural homeotic transformations in evolution are "apparent"."<BR/><BR/>No, that's not what I was saying at all. I'm saying that just because a structure looks similar to another (ex. panda's thumb, palatal ridges) don't immediately assume homeosis or meristic variation. <BR/><BR/>TupaiaAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-44586739893910135132007-09-24T14:13:00.000-04:002007-09-24T14:13:00.000-04:00HUH. I get you. Natural homeotic transformations i...HUH. I get you. Natural homeotic transformations in evolution are "apparent". They have been shaped by selection. They just happen to look exactly like the homeotic transfomations we can achieve in the lab. What a coincidence.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-17043461927253666942007-09-24T14:04:00.000-04:002007-09-24T14:04:00.000-04:00"when a homeotic transformation occurs, it is a qu..."when a homeotic transformation occurs, it is a qualitative, non-gradual change. Traits usually found in one part of the body now develop in another."<BR/><BR/>Again, tell us something we don't know. I was referring to APPARENT structural duplication or displacement.<BR/><BR/>TupaiaAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-66339641118252550742007-09-24T13:32:00.000-04:002007-09-24T13:32:00.000-04:00kaufman is also these guys that plunge into models...kaufman is also these guys that plunge into models and do not deal w¡enough with natural history. If Kaufman knew a bit more natural history, he may nt have been convinced by Manyard Smith. One biomathematician convinced another? Not so surprising. Models resist a lot. None of those guys has truly trustsnatural history. In this sense I am much more likely to sympathize with the very darwinian Mayr than with those guys.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-58373943178975042952007-09-24T13:27:00.000-04:002007-09-24T13:27:00.000-04:00What,do you think you make me angry? HahaPlease, g...What,do you think you make me angry? Haha<BR/>Please, go on tooting your selection horn.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-80336884185879186542007-09-24T13:19:00.000-04:002007-09-24T13:19:00.000-04:00Sanders: "Kaufman is not so hot."Too selectionist ...Sanders: "Kaufman is not so hot."<BR/><BR/>Too selectionist for you perhaps, especially after Maynard Smith influenced him?<BR/><BR/>Hey, I like Goldschmidt too. Properly contextualized within a selectionist paradigm, of course.<BR/><BR/>TupaiaAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-86258886777771158522007-09-24T13:18:00.000-04:002007-09-24T13:18:00.000-04:00did I say Sven? Sorry if I now and then confuse yo...did I say Sven? Sorry if I now and then confuse you guys..you are so...similar...A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-64799792628673156942007-09-24T13:13:00.000-04:002007-09-24T13:13:00.000-04:00"The apparent duplication of a structure does not ..."The apparent duplication of a structure does not necessarily mean that it occurred with a single regulatory mutation"<BR/><BR/>There could be a previous buildup of mutations up to a certain threshold, but when a homeotic transformation occurs, it is a qualitative, non-gradual change. Traits usually found in one part of the body now develop in another.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-24375695635314499732007-09-24T13:05:00.000-04:002007-09-24T13:05:00.000-04:00and you know what? Kaufman is not so hot.and you know what? Kaufman is not so hot.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-48642461883339542322007-09-24T13:03:00.000-04:002007-09-24T13:03:00.000-04:00"Adaptations based on multiple loci are not eviden..."Adaptations based on multiple loci are not evidence of selection; but rather drift and (nonadaptive) linkage"<BR/><BR/>Not true. They could perfectly constitute evidence for selection, specially if we have evidence of the corresponding selective condition, which is titally doable.<BR/><BR/>I ask, please, for the third time: Give me an example of a SIMPLE polygenic adaptation that has been shaped by selection.<BR/>I think my objection of the cichlid paper was clear enough. I am noit unfarily rejecting the case: Ia m questioning the assumption the oral jaw apparatus can be considered a metric trait o which the ACTUAL metric ttraits that compose it make and always "postive" contribution: only if they do this can they apply the test of selection they consider as "evidence".<BR/>I guess Sven and Windy are simply not smart enough to understand this objection. It already flew right past their heads once. <BR/><BR/>P.D. any frivolous attempt to label me will remain futile and pointless.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-47640202363311494182007-09-24T12:46:00.000-04:002007-09-24T12:46:00.000-04:00More panda's thumb moral:...or homeotic mutation, ...More panda's thumb moral:<BR/><BR/>...or homeotic mutation, for that matter.<BR/><BR/>The apparent duplication of a structure does not necessarily mean that it occurred with a single regulatory mutation.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-18975418539892742602007-09-24T12:34:00.000-04:002007-09-24T12:34:00.000-04:00Sanders: "If we think that mutations become readil...Sanders: "If we think that mutations become readily available for selection to favor"<BR/><BR/>That's a cartoon of selectionism.<BR/><BR/>Sanders: "mutations are discrete events (they are not always there) and that differences in the previous genetic compositions of both populations ... are very relevant to this story."<BR/><BR/>That's hardly news. Tell us something we don't know.<BR/><BR/>Panda's thumb: The moral of the story is not to make a default assumption of meristic mutation. <BR/><BR/>Razib, this is where Sanders is coming from (to save you the discovery process):<BR/><BR/>"Nor do complex adaptations constitute in themselves evidence for selection shaping an adaptation."<BR/><BR/>"(A) few mutations with large effect are behind the origin of new adaptations. In fact, there is no example that I know of where an adaptation has been shown to be have been shaped by an accumulation of several genes by natural selection."<BR/><BR/>In his view, selection does not produce or shape adaptations; it only increases or decreases the frequency of genotypes. Adaptations based on multiple loci are not evidence of selection; but rather drift and (nonadaptive) linkage.<BR/><BR/>Sanders rejects the positions of Gould and West-Eberhard as too orthodox. His views appear to be closest to Richard Goldschmidt, with nods to Francisco Varela (autopoiesis) and Stuart Kauffman (self-organization).<BR/><BR/>Is that fair, Sanders?<BR/><BR/>TupaiaAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-68397592593894725422007-09-24T12:31:00.000-04:002007-09-24T12:31:00.000-04:00Sanders bloviates:"it is false that adaptation = r...Sanders bloviates:<BR/>"<I>it is false that adaptation = result of natural selection.</I>"<BR/><BR/>Please see above where I point out that you don't know what you're talking about.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-83624252498956512672007-09-24T11:56:00.000-04:002007-09-24T11:56:00.000-04:00I don't know who you are talking to because that p...I don't know who you are talking to because that phrase "Oh no, the last two are not "evolution in action." is not mine. <BR/>I consider the PNAS article to make some interesting comparsions to andeans, and it's good they hunted down a hig saturation allele that is being selected. <BR/><BR/>But is selection all there is to high altitude adaptation? If we think that mutations become readily available for selection to favor, it is kind of weird that a younger high-altitude population, the andeans, offer no evidence for ongoing selection of any allele. This is what makes me suspect that mutations are discrete events (they are not always there) and that differences in the previous genetic compositions of both populations ("preadaptation", if you wish) are very relevant to this story. <BR/><BR/>Tupaia, your case with the panda thumbs simply demonstrates nothing. That's what I expect from an adaptationists: a theory of everything is a theory of nothing.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-28222532901775934922007-09-24T02:29:00.000-04:002007-09-24T02:29:00.000-04:00- High altitude adaptation in TibetansOh no, the l...<I>- High altitude adaptation in Tibetans</I><BR/><BR/><I>Oh no, the last two are not "evolution in action."</I><BR/><BR/>in case you didn't read the PNAS article referred to above, from the text:<BR/><I>Using these observations and assigning a Darwinian fitness coefficient of 1.0 to the women with the high-saturation genotype, the relative Darwinian fitness of women with the low-saturation genotype was only 0.44. For comparison, in the classic case of an environment with endemic falciparum malaria, a Darwinian fitness coefficient of 0.66 applies to homozygotes for normal hemoglobin A (51). High-altitude hypoxia may be an even stronger agent of natural selection than falciparum malaria. <B>These findings suggest that the frequency of the high saturation allele maybe increasing rapidly in the Tibetan population.</B></I><BR/><BR/>or is this not evidence enough?Razib Khanhttps://www.blogger.com/profile/09555115542918519593noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-85756046857602787722007-09-24T01:49:00.000-04:002007-09-24T01:49:00.000-04:00To me the problem with adaptationism is very simpl...To me the problem with adaptationism is very simple: it is false that adaptation = result of natural selection. <BR/>This unfortunate misunderstanding continuously presents the adaptationist with the tempation of considering a selective hypotheses as a "sufficient" explanation for the origin of any adaptation. His mind classifies everything else as secondary, footnote knowledge. Dawkins is such an adaptationist.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-20728666398031565852007-09-23T20:47:00.000-04:002007-09-23T20:47:00.000-04:00In my last post this paragraph should have include...In my last post this paragraph should have included an end quotation after the words biochemical geneticists:<BR/><BR/>That is what he is referring to when he states: "If a whole-organism biologist sees a genetically determined difference among phenotypes, he already knows he cannot be dealing with neutrality in the sense of the modern controversy among biochemical geneticists."<BR/><BR/>The following sentences were written by me not Dawkins: In other words he cannot be dealing with neutrality because there is a phenotypic effect. In the biochemists sense neutrality means there is no phenotypic effect.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-91689736677159386002007-09-23T20:45:00.000-04:002007-09-23T20:45:00.000-04:00This comment has been removed by the author.Unknownhttps://www.blogger.com/profile/13804851532982501989noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-11093535845128805692007-09-23T19:45:00.000-04:002007-09-23T19:45:00.000-04:00Larry Moran said... p-ter, Read carefully...<I>Larry Moran said...<BR/><BR/> p-ter,<BR/> <BR/> Read carefully. This—possibly hypothetical—scientist is saying that if there's a phenotype then it can't be neutral.<BR/><BR/> According to you, there are no scientists who hold this position. Right?</I><BR/><BR/>Larry I think you have to read your copy of <B>The Extended Phenotype</B> again. In fact if you google the passage you cite you can look it up in google books.<BR/><BR/>Dawkins says:"Adaptationist thinking, <B>if not blind conviction</B>, has been a valuable stimulator of testable hypothesis in physiology" and "I have tried to show that adaptationism can have virtues as well as faults" and "But this chapter's main purpose is...to list the main reasons why the student of adaptation should proceed with caution"<BR/><BR/>The two sentences just prior to what you cite might help to clarify:<BR/>"If there are neutral mutations in the biochemists' sense, what this means is that any change in polypeptide structure which they induce has no effect on the enzymatic activity of the protein. This means that the neutral mutation will not change the course of embryonic development, will have no phenotypic effect <I>at all</I> as a whole organism biologist would understand phenotypic effect." <BR/><BR/>That is what he is referring to when he states: "If a whole-organism biologist sees a genetically determined difference among phenotypes, he already knows he cannot be dealing with neutrality <B>in the sense of the modern controversy among biochemical geneticists</B>. In other words he cannot be dealing with neutrality because there <B>is </B>a phenotypic effect. In the biochemists sense neutrality means there is no phenotypic effect.<BR/><BR/>The very next sentences after your quotation are: "He might, nevertheless, be dealing with a neutral character in the sense of an earlier controversy (Fisher & Ford 1950; Wright 1951). A genetic difference could show itself at the phenotypic level, <B>yet still be selectively neutral</B>.<BR/><BR/>Now I have no right to be getting in on an argument between biologists of any stripe so I apologize if I have grossly misread this but it seems that you have misunderstood Dawkins' point. Maybe you should take your own advice and read carefully (or maybe I should just butt out).Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-44711475020075974342007-09-23T13:32:00.000-04:002007-09-23T13:32:00.000-04:00Let me correct my earlier post - the thumb of the ...Let me correct my earlier post - the thumb of the red panda originally aided in arborealism, a preadaptation to object manipulation. <BR/><BR/>http://www.pnas.org/cgi/content/full/103/2/3791<BR/><BR/>As for shaped by selection, this will be settled by developmental genetics. (I doubt that the fossil record will be so complete.)<BR/><BR/>What is with your fixation with the single step? Identifying the probable developmental trajectory of a trait change does not necessarily imply that such change must occurred in a single step, whether the trait in question is a pedomorphic hair pattern or a false thumb. The evolutionary expression of such a trajectory in any given case may well be - and in scores of cases, certainly was - in stages.<BR/><BR/>TupaiaAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-63019619130804509912007-09-23T10:36:00.000-04:002007-09-23T10:36:00.000-04:00Tupaia, how do you know these extra "digits" are "...Tupaia, how do you know these extra "digits" are "shaped by selection"?A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-1371508833610099022007-09-23T04:59:00.000-04:002007-09-23T04:59:00.000-04:00Sanders, if the giant panda had just been discover...Sanders, if the giant panda had just been discovered I bet that "mutationists" would have immediately assumed that its "thumb" is a Batesonian meristic mutation. As we all know, it isn't. Instead, it is testimony to the shaping power of selection acting on preexisting developmental programs. In fact, similar selective forces acting on the carnivore paw independently produced a similar mechanism of developmental change in the unrelated red panda.<BR/><BR/>(Do the thumbs of the two pandas also show that developmental programs bias the pathways selection-directed evolution can take? Sure.)<BR/><BR/>TupaiaAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-11793487443750128522007-09-22T22:08:00.000-04:002007-09-22T22:08:00.000-04:00Larry, touche :-)I take it back-- Dawkins does see...Larry, <BR/><BR/>touche :-)<BR/><BR/>I take it back-- Dawkins does seem to be arguing there that all phenotypic changes are selected. I'm actually surprised to see that.Joe Pickrellhttps://www.blogger.com/profile/03756271491303196763noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-19688889318489183542007-09-22T21:22:00.000-04:002007-09-22T21:22:00.000-04:00p-ter,Do you think there are any biologists who be...p-ter,<BR/><BR/>Do you think there are any biologists who believe that every visible mutation must be subject to selection? For example, do you think that Richard Dawkins could ever say something like this?<BR/><BR/><I>The biochemical controversy over neutralism is concerned with the interesting and important question of whether all gene substitutions have phenotypic effects. The adaptationism controversy is quite different. It is concerned with whether, given that we are dealing with a phenotypic effect big enough to see and ask questions about, we should assume that it is the product of natural selection. The biochemist's 'neutral mutations' are more than neutral. As far as those of us who look at gross morphology, physiology and behaviour are concerned, they are not mutations at all. It was in this spirit that Maynard Smith (1976b) wrote: "I interpret 'rate of evolution' as a rate of adaptive change. In this sense, the substitution of a neutral allele would not constitute evolution ..." If a whole-organism biologist sees a genetically determined difference among phenotypes, he already knows he cannot be dealing with neutrality in the sense of the modern controversy among biochemical geneticists.</I><BR/><BR/>Read carefully. This—possibly hypothetical—scientist is saying that if there's a phenotype then it can't be neutral.<BR/><BR/>According to you, there are no scientists who hold this position. Right?Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.com