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Author: bdhinton Big gold star, 5000 posts 10+ Year Anniversary! Old School Fool Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: of 25067  
Subject: New model of evolution Date: 11/17/2011 8:31 AM
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A new study (Hughes 2011) in the Nature Publishing Group journal Heredity proposes a new non-Darwinian mechanism for the origin of adaptive phenotypes. Its author, Austin L. Hughes of the University of South Carolina, pioneered statistical methods for detecting positive selection at the molecular level with geneticist Masatoshi Nei (Hughes & Nei 1988). He later had the hubris in 2007 to question the majority of inferences to positive selection based on those methods (Hughes 2007). Now he's proposing a mechanism for adaptive evolution that renders Darwin unnecessary.

If positive selection may be thought of as the promulgator of novelties, purifying selection is the damage control. The latter is an easy affair; selection has only to "nip in the bud" any mutations that render an organism disadvantaged. However, only the former is Darwinian, and it is much more ambitious; positive selection may only act effectively on a mutation that increases the fitness of an organism's phenotype so as to overwhelm random noise. It must then, through repeated generations of differential survival, succeed in replacing all inferior genotypes with the newcomer. The difficulty of completing this process in a sufficient amount of time, an issue raised by Haldane, was a leading impetus for Kimura's neutral theory (Kimura 1969, 1983).

It is in the spirit of that question that Hughes now proposes a model he refers to as the plasticity-relaxation-mutation (PRM) model.

http://www.evolutionnews.org/2011/11/no_positive_selection_n...
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