Mapping of autosomal male-determining factors of the housefly, Musca domestica L., by using a female-determining factor

Abstract

A procedure to locate autosomal male-determining factors (A^M) of the housefly is described, which employs a female-determining factor (F) marked with a closely linked dominant gene. A total of 70 A^M chromosomes extracted from four II^M strains, nine III^M strains and three V^M strains of different geographic origins were examined. On the basis of female recombination frequencies, two to three types of A^M chromosomes were found in each of the linkage groups, suggesting that the A^M chromosomes are polymorphic for chromosome aberrations. All the A^M factors were mapped to a specific site or closely linked sites on the respective autosomes. From the comparison of the mitotic autosome figures and the female recombination maps of A^M chromosomes, it is suggested that A^M factors are located near the centromeres of autosomes. The validity of this technique and the possible mechanisms for the origin of M polymorphism are discussed.