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Seismic shift of paradigm in molecular evolution

Posted by forsdyke on 27 Dec 2010 at 21:09 GMT

That Rocha and Feil refer to a "seismic shift" is much welcomed. Their table of "variables historically proposed to explain GC variation in prokaryotes" criticizes a 1996 paper that I authored as not explaining "why there are traces of pervasive selection only for GC." This opaque remark prompted a brief email correspondence that still leaves me puzzled.

The authors seem to believe that, under my hypothesis, phylogenetically related organisms occupying the same environment should have a wider GC variance than unrelated organisms (to prevent recombination), but they believe the evidence does not support this. Yet the 1996 paper gives, as examples, the wide variance in GC between phylogenetically related viruses that occupy a common host cell. Certainly a wide variance would be expected in the early stages of speciation, prior to the appearance of other forms of anti-recombination (less likely in viruses).

The authors also maintain that phylogenetically unrelated organisms in similar environments have close GCs because there is a common environmental selection pressure that affects GC. For full discussion of GC please see the 2nd edition of my textbook - Evolutionary Bioinformatics (Springer, New York, 2011).

No competing interests declared.