Assessing the putative roles of X–autosome and X–Y interactions in hybrid male sterility of the Drosophila bipectinata species complex

Interspecific F1 hybrid males of the Drosophila bipectinata species complex are sterile, while females are fertile, following Haldane’s rule. A backcross scheme involving a single recessive visible marker on the X chromosome has been used to assess the putative roles of X–autosome and X–Y interactions in hybrid male sterility in the D. bipectinata species complex. The results suggest that X–Y interactions are playing the major role in hybrid male sterility in the crosses D. bipectinata × D. parabipectinata and D. bipectinata × D. pseudoananassae , while X–autosome interactions are largely involved in hybrid male sterility in the crosses D. malerkotliana × D. bipectinata and D. malerkotliana × D. parabipectinata. However, by using this single marker it is not possible to rule out the involvement of autosome–autosome interactions in hybrid male sterility. These findings also lend further support to the phylogenetic relationships among 4 species of the D. bipectinata complex.