[Taxacom] Non-coding traits can suffer convergent adaptation

[Richard Zander]

I came across this interesting publication, listed here with a partial extract of the abstract:

 

Amorós, D., S. Bedhomme, M. Hermann & I. G. Bravo. 2010. Evolution in regulatory regions rapidly compensates the cost of nonoptimal codon usage. Molecular Biology and Evolution 27: 2141-2151.

 

"By mimicking the horizontal transfer of an antibiotic resistance gene, we established that a nonoptimal codon usage renders Escherichia coli 10-20 times more sensitive to the antibiotic. After 350 generations of experimental evolution under antibiotic selection pressure, this cost was compensated through both in cis changes in the gene promoter and in trans changes in the host bacterial genome, without introducing mutations in the coding sequence of the resistance gene. Further, we have found experimental evidence for convergent molecular adaptive evolution. ... Our results highlight the importance of rapid evolution of regulatory mechanisms in the adaptation to new environmental and genetic situations."

 

If BOTH genes and non-coding traits are possibly affected by adaptive forces, then convergence is not only the province of morphology, but also of the genome. Sure SINES and the like seem fixed randomly and too precisely to be convergent, but is SINE production maybe sufficiently common that there is selection, exact selection, involved on its placement such that it affects exactly some cis regulation/promotion of some nearby gene?  It would be nice to identify conservative neutral DNA sequences similar to the conservative neutral (found in many environments) morphological traits of quandam virtue. Otherwise, what if selection on multiple gene/noncoding sequences is so pervasive that the genome is commonly convergent to the same habitats as the phenome? I think someone told me I was worried about nothing a while back about this very subject. Am I? Is the answer statistical? 

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Richard H. Zander 
Missouri Botanical Garden, PO Box 299, St. Louis, MO 63166-0299 USA 
Web sites: http://www.mobot.org/plantscience/resbot/ and http://www.mobot.org/plantscience/bfna/bfnamenu.htm
Modern Evolutionary Systematics Web site: http://www.mobot.org/plantscience/resbot/21EvSy.htm