Evolution: a different view with loss of traits; not Behe (Introduction)

by dhw, Thursday, September 17, 2020, 10:34 (1528 days ago) @ David Turell

dhw: My theory, proposed in response to your version of Behe’s theory, concerns speciation. But mutations within existing species which lead to variations within that existing species are irrelevant to the subject of speciation! Has the human gene study now proved that no species in the history of life has ever contained new genes? My theory is that speciation entails the production of new genes (you now agree they exist), new uses for old genes (do you disagree?), and the discarding of genes that are no longer of any use. Now please tell me which of these proposals you object to, and why you think that speciation can only be achieved by loss of genes.

Because Behe's entire book is a recitation of gene loss in several different branches of life: woolly mammoths, Yersinia pestis, African cichlid, dog breeding, etc. His whole point is change by DNA loss.

I understand, but you have told us that his examples refer to changes within existing species, and this “may well tell us how speciation occurs”. But it clearly doesn’t at the moment, according to your presentation of Behe. (I’m not arguing with Behe but with you.) The example you gave us (polar bears having lost genes that are found in grizzly and brown bears) can simply be explained by the fact that different environments make certain genes unnecessary. And I do not think the polar bear counts as an “advance” on other varieties of bear.

DAVID: And of course the necessity for intelligent design. New genes may appear but how much are they expressed and to what degree? Behe never shows changes due to new genes. But of course that is not his point. I am not aware of any study that shows new genes producing anything of importance. Behe even shows the Lenski E. coli study has not produced anything of great importance, just minor changes in the metabolism of the same species.

I must commend you yet again for your integrity in drawing our attention to this article, which invalidates the above:

"New University of Colorado Boulder-led research finds that the traits that make vertebrates distinct from invertebrates were made possible by the emergence of a new set of genes 500 million years ago, documenting an important episode in evolution where new genes played a significant role in the evolution of novel traits in vertebrates. (David’s bold)

DAVID: This certainly shows new genes creating new species in vertebrates. So what is Behe showing? Note my bold. This is early speciation in evolution. Perhaps what Behe is showing is the speciation mechanism in late evolution only. The story still unfolds.

Yes indeed, and may I suggest that this story provides support for my proposal, though I’m happy to modify this by omitting “ongoing” and even “constant”: the process of evolution entails the acquisition of new genes (or new functions for old genes) and loss of unwanted genes, which will be weeded out by natural selection. Now please tell me your objections. Your example above also argues against the theory that evolutionary “advances always result from loss of genes”.