August 12, 2007

It's the Economy, Stupid: Another Creationist Argument Blown Away

I wrote a few days ago of one common Creationist argument that doesn't hold up to any degree of scrutiny, like the vast majority of them. Today, as they say, another one bites the dust.

This other now-defunct argument runs along the lines of, "Well, if chimps and humans have DNA that's 99% the same, how come there are chimps and humans? Must be the intelligent designer at work!" The conclusion doesn't follow from the premise, of course, but remember who we're talking about. I doubt that "be logical today" is even in the top ten items on their "things to do" list.

In theory — and by this I mean scientific theory as it would be recognized by those concerned with evo-devo and development in general — one would expect many such differences to arise because of differences in the mechanisms of gene expression. Different genes are turned on and off at different times, for different durations, perhaps in a different sequence, etc., in the species under consideration. This was largely hypothetical to date because there hadn't been a fairly broad survey of gene expression in various primates and humans.

That's changed now, and what the theory predicted has been born out in hard science. Researchers at Duke University have compared regulatory sequences from well over 6,000 genes each from humans, chimpanzees and rhesus macaques. The last two have genomes that are ~99% and ~88% similar to that of humans. Lo and behold, do hold the key to why we're so similar to our ape cousins at one level and yet so different at another. No intelligent design required, just another level of genetic encoding resulting in different binding sites for the necessary proteins to start the process of transcription and so ultimately altering translation and expression.

The study in question is in press currently:

Haygood, R.H., Fedrigo, O., Hanson, B., Yokoyama, K-D., and G.A. Wray. Promoter regions of many neural- and nutrition-related genes have experienced positive selection during human evolution. Nature Genetics
A release with more information is also available from EurekAlert!

So, how come all those "creation science" researchers haven't published anything on this subject, hmmmmmmmm? Oh, yeah... because they don't actually do any research. Almost forgot about that. No sense getting too concerned with that "pathetic level of detail" now, eh?

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