Evidence of a high rate of selective sweeps in African Drosophila melanogaster.
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.
Mousset
Sylvain
S
Laboratoire d'Ecologie, Ecole Pratique des Hautes Etudes, Université Pierre et Marie Curie, 75005 Paris, France.
Brazier
Lionel
L
Cariou
Marie-Louise
ML
Chartois
Frédérique
F
Depaulis
Frantz
F
Veuille
Michel
M
D000354:Africa, Western; D000818:Animals; D001483:Base Sequence; D007446:Chromosome Inversion; D004331:Drosophila melanogaster / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA