A male-determining factor on autosome 1 and occurrence of male-recombination in the housefly, Musca domestica L..

Abstract

Linkage analyses of sex-determining factors in a Fijian housefly strain, Suva Dump Fiji (SDF), were performed by using genetically marked autosomes. Although a Y chromosome could not be detected, the presence of at least three kinds of autosomal male-determining factors, IM, IIM and IIIM, was demonstrated in males of this strain. Both males and females of this strain carried the IIM-chromosome in the homozygous state. In addition, the females carried a fourth chromosomal female determining factor (F), which acts epistatically over the plural number of M factors.It is known that no crossing-over occurs in normal XY-type housefly males. However, XX males heterozygous for the IM-chromosome extracted from the SDF strain and a acv by marker chromosome produced recombinants with very low frequency. These recombinants seemed to be the resultants of male crossing-over at the meiotic cell stage. On the basis of male-recombination data, the M factor on the first chromosome was mapped on the right side of by locus.

Location of fourth chromosomal male-determining factors of the housefly, Musca domestica.

“…recombinants (14/74), suggesting that male-recombination takes place mostly at the meiotic cell stage. Similar results have been observed among the IM chromosomes of Fijian origin (Inoue and Hiroyoshi 1982). However, the very recovery of clusters of reciprocal recombinants (9/74), 4 + + + females and 5 Ba rl ye males ( Table 2), indicates that male recombination could also occur in spermatogonial cells.…”

“…Transposition of M factors mediated by a transposable element(s) has been suggested as a cause of M factor polymorphism (Green 1980 Usually, the AM factors of M. domestics are difficult to locate, because little or no recombination takes place in the male. Earlier, two laborious approaches have been made to map the AM factors: one approach made use of exceptional male-recombinations (Inoue and Hiroyoshi 1982;Hiroyoshi, Fukumori and Inoue 1982) and the other employed both genetic and cytological analyses (Rubini and Franco 1972;Rovati et al 1983). Recently, we have developed an efficient procedure for mapping the AM factors, and have demonstrated that three IM, four JIM, twelve IIIM and three VM factors of different geographic origins are all located at a single or closely linked site(s) on the respective autosomes Inoue and Hiroyoshi 1984).…”

Male crossing-over and location of the male determining factor on the third chromosome in a IIIm-type strain of the housefly.

“…However, as was already pointed out by Hiroyoshi (1960 and, one cannot be certain whether the "recombinants" were the results of crossing-over in the males or perhaps due to some other causes. Recently, we examined various strains of AM-type, including IM, JIM, IIIM and VM, and observed low frequency occurrences of male recombination from every strain (Hiroyoshi and Fukumori 1976;Fukumori and Hiroyoshi 1977;Hiroyoshi 1980 and1982). The frequencies of male recombination observed from these strains were just about the proportion as seen in the data presented in this report.…”

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

“…AM chromosomes used were extracted according to the procedure described by Inoue and Hiroyoshi (1982) either from old laboratory strains or from field collected strains. These strains, listed in Table 1, had been maintained by mass-matings.…”