A method for detecting effect of beneficial mutations in natural populations ofDrosophila melanogaster

Abstract

SummaryAn experimental method is proposed for detecting the effects of positive natural selection on DNA polymorphisms. Since beneficial mutations are expected to increase in frequency faster than neutral mutations, variants which have reached high frequencies in a relatively short period could be linked to some beneficial mutation.D. melanogasterhas a cosmopolitan polymorphic inversion -In(2L)t- whose age in some local populations has been estimated. Setting the age ofIn(2L)tas the upper limit for the age of variants, we searched for variants whose frequencies were possibly influenced by positive natural selection. We detected a single candidate whose frequency and distribution met the requirements imposed by our method.