Behe on Darwin: polar bear discussion (Introduction)

by David Turell , Thursday, March 07, 2019, 01:37 (2090 days ago) @ David Turell

A review of the gene that protects polar bears from their high fat diet:

https://evolutionnews.org/2019/03/lessons-from-polar-bear-studies/

"This is the first in a series of posts responding to the extended critique of Darwin Devolves by Richard Lenski at his blog, Telliamed Revisited.

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"For polar bears, having mutated APOB genes protects them from a high fat diet. If those polar bear mutations decreased the activity of APOB by half or more, then we might expect a similar protective effect as was seen in the mouse. Given that computer analysis also estimated the APOB mutations in the polar bear as likely to be damaging, it is most reasonable to think the activity of the protein has been blunted by the mutations.

"Thus there is no good reason to speculate about possible new activities of the coded protein in the polar bear. Rather, the simplest hypothesis is that the mutations in the polar bear lineage that were judged by computer analysis as likely to be damaging did indeed blunt the activity of the APOB protein in that species — that is, made it less effective. That molecular loss gave rise to a happy, higher-level phenotypic result — an increased tolerance of polar bears for their high fat diet.

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" The caveats mentioned above by Professor Lenski — about how computer-assignment of a mutation as “damaging” is not a guarantee, and that the protein may have secretly gained some positive new function — are correct. He is also quite right to say that without detailed biochemical and other experiments we cannot know for sure how the change affected the protein and the larger system at the molecular level. Nonetheless, computer methods of analyzing mutations are widely used because they are generally accurate. And they do not suddenly lose their accuracy when I cite their results. So, in the absence of specific information otherwise, that’s the way for a disinterested scientist to bet. There is no positive reason — other than an attempt to fend off criticism of the Darwinian mechanism — to doubt the conclusion. (my bold)

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"The APOB gene is exceptional in having such detailed research done on it. Most other genes haven’t been so closely investigated. Nonetheless, in the absence of positive evidence to doubt a prediction for a specific case, the results of the computer analysis should be tentatively accepted for other genes to which it has been applied as well. Skepticism on the matter seems to stem less from the data than it does from reflexive defensiveness.

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"I’d like to highlight one final critical point. Let me set it up with a homey analogy. When I was 14 I worked weekends at McDonald’s, and sometimes I’d be assigned to operate the milkshake machine. The machine was broken down each night for cleaning. One of my tasks early in the morning before opening was to reassemble its parts. There were maybe a dozen parts to put together — sprockets, clamps, gaskets, and such. Shakes were very popular back then (mid 1960s) and made many customers happy for a while. Nonetheless, there were maybe a dozen parts to put together — sprockets, clamps, gaskets, and such. Shakes were very popular back then (mid 1960s) and made many customers happy for a while. Nonetheless, the function of the parts of a shake machine is not “to make people happy.” The function of a sprocket or a clamp isn’t even “to make a milkshake.” Rather, they have lower-level mechanical duties that are subservient to the overarching higher purposes of the systems.

"The same is true of APOB. Its function is not “to help polar bears survive,” nor even “to clear cholesterol.” Rather, it has one or more lower level functions that are subservient to those higher purposes. Thus the fact that cholesterol might be cleared more efficiently in polar bears does not at all mean that APOB hasn’t been degraded, any more than breaking the off-switch of a shake machine so that it works continuously throughout lunch hour means some new improved function was added.

"In both Darwin Devolves and my Quarterly Review of Biology paper on which it is based, I repeatedly stressed the need to look beneath higher-level, phenotypic changes to associated underlying molecular-level mutations. Did they help by constructing or by degrading what I termed Functional Coded elemenTs (FCTs)? Helpful higher level changes can often be misleading, because they might actually be based on degradative molecular changes. There is every reason to think that’s what occurred in the evolution of the examples I cite in Darwin Devolves, definitely including the magnificent Ursus maritimus. The more effective clearance of its cholesterol allows the polar bear to thrive on a diet of seal blubber, but it is the result of a mutation that breaks or blunts APOB.

Comment: I've had his book for 48 hours. Just as he tells the story above at age 14, he describes his Catholic background and that he fully swallowed Darwin evolution until he became a college biology/biochemistry professor and began to read the research over the past 30-40 years. Like myself he was totally converted by reason! The research offers no reasoned support for Darwin's theory. Note the obvious confirmation bias from Lenski.