A especiação como uma força ativa promovendo a evolução genética

quarta-feira, dezembro 23, 2009

Trends in Ecology & Evolution
Volume 25, Issue 1, January 2010, Pages 14-20

Speciation as an active force in promoting genetic evolution

Chris Venditti1 and Mark Pagel1,2

1 School of Biological Sciences, University of Reading, Reading RG6 6BX, UK

2 Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA


There is a growing appreciation among evolutionary biologists that the rate and tempo of molecular evolution might often be altered at or near the time of speciation, i.e. that speciation is in some way a special time for genes. Molecular phylogenies frequently reveal increased rates of genetic evolution associated with speciation and other lines of investigation suggest that various types of abrupt genomic disruption can play an important role in promoting speciation via reproductive isolation. These phenomena are in conflict with the gradual view of molecular evolution that is implicit in much of our thinking about speciation and in the tools of modern biology. This raises the prospect of studying the molecular evolutionary consequences of speciation per se and studying the footprint of speciation as an active force in promoting genetic divergence. Here we discuss the reasons to believe that speciation can play such a role and elaborate on possible mechanisms for accelerated rates of evolution following speciation. We provide an example of how it is possible detect whether accelerated bursts of evolution occur in neutral and/or adaptive regions of genes and discuss the implications of rapid episodes of change for conventional models of molecular evolution. Speciation might often owe more to ephemeral and essentially arbitrary events that cause reproductive isolation than to the gradual and regular tug of natural selection that draws a species into a new niche.


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