Differences inPelement population dynamics between the sibling speciesDrosophila melanogasterandDrosophila simulans

Abstract

SummaryPatterns ofPelement establishment and evolution were compared in populations of D.melanogasterand D.simulans. For each species, mixed populations were initiated withMstrain flies lackingPelements together withPstrain flies having similarPelement copy numbers and phenotypes. The mixed populations were subsequently maintained under similar environmental conditions. On the basis of gonadal sterility assays,Pelements tended to be significantly more active inD.melanogasterthan inD.simulanspopulations. This activity difference between the two species was positively associated withPelement copy number, determined by restriction enzyme analysis, and transposition frequency, as determined by a transposition assay. Host factors are the most likely explanation for the observed species variation. Difficulty of establishment may be a factor determining the absence ofPelements in natural populations ofD.simulans.