Zusammenfassung
Drosophila melanogaster from Zimbabwe and nearby
regions shows strong but asymmetric sexual isolation from its
cosmopolitan counterparts. By creating stable chromosome-substitution
lines, earlier studies were able to show that the two major autosomes
have very large effects on both male mating success and female mating
preference. In this study, we genetically dissect this sexual isolation
by recombination analysis between a whole-chromosome substitution line
(which carries a Zimbabwe-derived third chromosome) and a strain with
seven visible markers on that chromosome. Four loci are responsible for
male mating success and three others are found to control female mating
preference. Because male and female traits are not closely linked,
their strong association among isofemale lines is most likely a
reflection of sexual selection in nature. The results suggest that a
large number of behavioral loci may evolve concurrently in the
incipient stage of speciation before other aspects of reproductive
isolation (such as hybrid sterility) have become evident. The results
shed light on the population genetic processes underlying the formation
of nascent species, as well as modes of speciation.
Nutzer