Evidence of a High Rate of Selective Sweeps in African Drosophila melanogaster
a Laboratoire d'Ecologie, Ecole Pratique des Hautes Etudes, Université Pierre et Marie Curie, 75005 Paris, Francej*wl, 百拇医药
b Laboratoire Populations Génétique et Evolution, CNRS, 91198 Gif-sur-Yvette-cedex, Francej*wl, 百拇医药
ABSTRACTj*wl, 百拇医药
Assessing the rate of evolution depends on our ability to detect selection at several genes simultaneously. We summarize DNA sequence variation data in three new and six previously published data sets from the left arm of the second chromosome of Drosophila melanogaster in a population from West Africa, the presumed area of origin of this species. Four loci [Acp26Aa, Fbp2, Vha68-1, and Su(H)] were previously found to deviate from a neutral mutation-drift equilibrium as a consequence of one or several selective sweeps. Polymorphism data from five loci from intervening regions (dpp, Acp26Ab, Acp29AB, GH10711, and Sos) did not show the characteristic deviation from neutrality caused by local selective sweeps. This genomic region is polymorphic for the In(2L)t inversion. Four loci located near inversion breakpoints [dpp, sos, GH10711, and Su(H)] showed significant structuring between the two arrangements or significant deviation from neutrality in the inverted class, probably as a result of a recent shift in inversion frequency. Overall, these patterns of variation suggest that the four selective events were independent. Six loci were observed with no a priori knowledge of selection, and independent selective sweeps were detected in three of them. This suggests that a large part of the D. melanogaster genome has experienced the effect of positive selection in its ancestral African range.j*wl, 百拇医药
YEARS after the neutralist challenge to the Darwinian theory (KIMURA 1968 ), the interpretation of molecular variation still rests on an unresolved combination of the two main mechanisms of genetic change, selection and drift. Our difficulty in integrating these mechanisms bars us from properly using genomic data for assessing the level of natural selection involved in species evolution. An illustration of this inability can be found in the disagreement among studies on the scale at which hitchhiking events must be investigated in the genome (MAYNARD SMITH and HAIGH 1974 ; KAPLAN et al. 1989 ). A study of the extent of a selective sweep on flanking regions in the Drosophila genome found a significant reduction in variation over(Sylvain Mousset Lionel Brazier Marie-Louise Cariou Frédérique Chartois Frantz Depaulis and Michel )
b Laboratoire Populations Génétique et Evolution, CNRS, 91198 Gif-sur-Yvette-cedex, Francej*wl, 百拇医药
ABSTRACTj*wl, 百拇医药
Assessing the rate of evolution depends on our ability to detect selection at several genes simultaneously. We summarize DNA sequence variation data in three new and six previously published data sets from the left arm of the second chromosome of Drosophila melanogaster in a population from West Africa, the presumed area of origin of this species. Four loci [Acp26Aa, Fbp2, Vha68-1, and Su(H)] were previously found to deviate from a neutral mutation-drift equilibrium as a consequence of one or several selective sweeps. Polymorphism data from five loci from intervening regions (dpp, Acp26Ab, Acp29AB, GH10711, and Sos) did not show the characteristic deviation from neutrality caused by local selective sweeps. This genomic region is polymorphic for the In(2L)t inversion. Four loci located near inversion breakpoints [dpp, sos, GH10711, and Su(H)] showed significant structuring between the two arrangements or significant deviation from neutrality in the inverted class, probably as a result of a recent shift in inversion frequency. Overall, these patterns of variation suggest that the four selective events were independent. Six loci were observed with no a priori knowledge of selection, and independent selective sweeps were detected in three of them. This suggests that a large part of the D. melanogaster genome has experienced the effect of positive selection in its ancestral African range.j*wl, 百拇医药
YEARS after the neutralist challenge to the Darwinian theory (KIMURA 1968 ), the interpretation of molecular variation still rests on an unresolved combination of the two main mechanisms of genetic change, selection and drift. Our difficulty in integrating these mechanisms bars us from properly using genomic data for assessing the level of natural selection involved in species evolution. An illustration of this inability can be found in the disagreement among studies on the scale at which hitchhiking events must be investigated in the genome (MAYNARD SMITH and HAIGH 1974 ; KAPLAN et al. 1989 ). A study of the extent of a selective sweep on flanking regions in the Drosophila genome found a significant reduction in variation over(Sylvain Mousset Lionel Brazier Marie-Louise Cariou Frédérique Chartois Frantz Depaulis and Michel )