Molecular-genetic analysis of hobo polymorphism in the genome of Drosophila melanogaster lines subjected to long-term selection

The distribution of mobile genetic element hobo was examined in Drosophila melanogaster lines HA (high male mating activity) and LA (low male mating a ctivity) before and after their isogenization using Southern blot hybridiza tion. The probe containing a full-size hobo copy was shown to produce polym orphic multilocus hybridization with chromosomal DNA. The polymorphism was line-specific. A comparison of hybridization patterns in isogenic and origi nal lines showed that isogenization in dysgenic crosses resulted in the app earance of additional hobo localization sites in LA but not in HA. The hobo destabilization in the LA genome correlated with genetic instability and t he ability to induce H-E hybrid dysgenesis. The results obtained are discus sed in relation to the possible role of hobo in inducing genetic variabilit y in lines with low male mating activity, which may counteract deleterious consequences of inbreeding and selection in the negative direction.