Gradualism in Evolution not supported by genome studies (Agnosticism)

by David Turell , Monday, October 12, 2020, 15:47 (1502 days ago) @ dhw

DAVID: Behe is a pioneer in theory just like Shapiro. He does use the polar bear as a prime example of species change. You are correct. it is really a massive adaptation to specific environment. He also discusses the mammoth and its DNA differences from elephants, in which it is found between 500-800 genes were degraded. His book is filled with such examples of adaptation by gene degradation. His prime thought early in the book to quote is: "Darwin's mechanism works chiefly by squandering genetic information for short-term gain." By this he means adaptation which aids survival "by damaging or breaking genes." (pages 37-38) By no means does he says he is positive full speciation in evolution is the cause of speciation, but he feels he is offering strong evidence in a 342 page book filled with adaptive examples. All dog varieties are due to damaged/degraded genes, but following your thought they are still really mostly wolves, as shepherd/wolves exist. Susan and I have been to a local breeding/rescue ranch out of curiosity..

dhw: Thank you for this revealing summary. It's a far cry from “advances always result from loss of genes”, and indeed it is pretty clear that the examples don’t even deal with advances! A polar bear can hardly be called an advance on a grizzly bear! It is perfectly logical that adaptation should RESULT in loss of genes since genes necessary for one environment may be of no use in another. I would suggest that adaptations will primarily involve new functions for existing genes, though some new ones may be necessary, but major innovations will certainly require new genes.

DAVID: Relax from your old teachings and beliefs. The bold is specifically not proven. Much is shown to be accomplished by reduplication, alterations in expressions, and setting up of new genome-wide networks among existing genes.

dhw: What old teachings and beliefs? Initially you were sceptical about the very existence of new genes! I didn’t say it was proven – it is my suggestion, but what else do you think new genes would be required for if not for innovation? The rest of what you say is covered by new functions for old genes.

DAVID: The polar bear difference is somewhat more than fur color but I'll buy adaption along with you. The mammoth is very different in appearance, but again it is an elephant with a woolly hide and giant tusks. Phenotype used for classification is useless. DNA study is the true guide to evolution. We both know this. Behe, with his emphasis on DNA, is pursuing a valid approach to cracking open the issue of speciation.

dhw: That may be so, but his theory as you have presented it quite patently does not even begin to prove that speciation is caused by loss of genes, or that "advances always result from loss of genes", which was the claim that started this discussion.

Well, we have clarified Behe's theory and it is highly suggestive of gene loss playing a major role in speciation since adaptation is mainly from gene degradation. However adaptation does not lead to speciation in the fossil record. Speciation creates gaps. Darwin's gradualism is not proven. Shapiro's theory is another approach, bootstrapping by editing DNA. This is all we have and in comparison I like Behe's approach better since it encompasses a review of genetic evidence. Shapiro is an extrapolation from free-living bacteria. And all Lenski has shown in his E. coli studies is some mutational adaptations in the same species.