Mapping of autosomal male-determining factors of the housefly, Musca domestica L., by means of sex-reversal.

A female determining factor (F), epistatic to M factors, was used to map autosomal male determining factors (AM) of the housefly. On the basis of meiotic recombination frequency occurring in the sex-reversed females caused by F, three IM factors and two IIIM factors of different geographic origins were mapped in the close vicinity of the bp and the pw locus, respectively. These results suggest that AM factors occupy a definite site on the respective chromosomes. As measured along the IM and the IIIM chromosomes, the distribution of recombination in the sex-reversed females was strikingly different from that observed in the male. It is proposed that AM factors are located in the centric heterochromatin.