Going My Way?

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Science  17 Oct 2008:
Vol. 322, Issue 5900, pp. 349
DOI: 10.1126/science.322.5900.349a

Genetic hitchhiking refers to the non-neutral fixation of nonselected alleles because of their physical proximity to loci under selection. If ecologically relevant loci are under divergent selection between populations, such as may occur during speciation, it may reduce recombination and further isolate these genomic regions, which in turn can facilitate the evolution of reproductive isolation. Via and West have tested this theory by measuring genetic differentiation in diverging host races of pea aphids found on clover and alfalfa. The authors identified highly diverged markers between aphids found on the different host plants, in particular near putative loci associated with ecologically important traits, and found that genetic differentiation between races extended much farther away from the loci under selection than expected. Divergence was also much less pronounced at markers linked to selected loci among aphids that shared the same crop type, even when these crops were geographically distant. — LMZ

Mol. Ecol. 17, 4334 (2008).

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