Monday, March 12, 2007

An operational definition of the neutral theory?   posted by p-ter @ 3/12/2007 06:12:00 PM

I've often had the impression that debates about the neutral theory of molecular evolution are made confusing by people not defining their terms. Qualitative statements like "drift is more important than selection" tend to get tossed around. So this is from a recent paper:
This theory [the neutral theory] posits that the overall pattern of DNA evolution can be accounted for by mutation, genetic drift, and negative selection. It does not deny the operation of positive selection on some loci but only asserts that the overall pattern of genomic evolution can be explained without invoking adaptive evolution. Presumably, adaptive changes at any given time involve too small a fraction of the genome to be a statistically significant factor, despite their overwhelming biological significance.
I wonder if this is a generally accepted definition. If so, can the neutral theory officially be declared dead (at least for the protein-coding regions of the genome in Drosophila and human)?

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