Linkage and Sex Limitation of Several Loci in the Housefly

1984

A procedure to locate autosomal male-determining factors (AM) of the housefly is described, which employs a female-determining factor (F) marked with a closely linked dominant gene. A total of 70 AM chromosomes extracted from four IIM strains, nine IIIM strains and three VM strains of different geographic origins were examined.On the basis of female recombination frequencies, two to three types of AM chromosomes were found in each of the linkage groups, suggesting that the AM chromosomes are polymorphic for chromosome aberrations.All the AM 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 AM chromosomes, it is suggested that AM 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.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

1984

“…The sex of an individual fly is determined by the presence or absence of the Y-chromosome on which a male-determining factor is located (Hiroyoshi 1964;Rubini and Palenzona 1967). Besides the Y chromosome of a normal male, the existence of autosomal male-determining factors (AM) such as IIM, IIIM and VM have been demonstrated in various housefly strains (Sullivan 1958;Wagoner 1969). In some strains, a dominant female determining factor (F), epistatic to M factors, also participates in the sex determination (Rubini 1967;Wagoner 1969).…”

Section: Introductionmentioning

confidence: 99%

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

1982

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.

“…Although male crossing-over is not usually observed in the standard type housefly (Hiroyoshi 1960), exceptional occurrences of recombination among several loci of the third linkage group were observed when heterozygous males for recessive marker genes were testcrossed to homozygous mutant females (Milani and Travaglino 1957;Sullivan 1961;Hiroyoshi 1964). 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.…”

Section: Discussionmentioning

confidence: 99%

“…When those males were crossed to females carrying recessive mutant markers belonging to certain autosomal linkage groups, the mutant characters were recovered only in the female progenies in the F2 and in subsequent generations, but never in the male progenies. According 1) Present address: Cell and Developmental Biology Laboratory, Faculty of Integrated Arts and Sciences, Hiroshima University, Hiroshima 730. to genetic analyses done for some of those anomalous males, Sullivan (1961) first interpreted the peculiar phenomenon as the result of attachment or reciprocal translocation involving the Y chromosome and an autosome , and symbolized them as T( Y; A). Unfortunately, such an attachment or translocation could not be demonstrated by karyological examinations , but instead, strange facts indicated that those males lost the Y chromosome and were apt to possess two X chromosomes in addition to a set of normal-sized autosomes (Hiroyoshi, 1964).…”

Section: Introductionmentioning

confidence: 99%

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

Fukumori

1982

A dominant wing-shape mutation, Bx2 (Beadex2), occurring on the IIIMchromosome was found in a wild-type housefly strain named Nagai. By backcrossing hybrid males between the Bx2 male and the third chromosomal mutant bwb ge females to the homozygous recessive mutant females, a new type of sex-limited strain designated as "bwb ge/Bx2 M(Nagai)" was established. The strain usually kept producing only male progeny with Bx2 phenotype and the female progeny with bwb ye phenotype, but the recombinant type offspring also segregated although the frequency was very low. Further analyses of these recombinants indicated that some of them were the resultants of crossing-over in the male parents, but the others were not. By using the male crossing-over data, the location of the male determining factor on the third chromosome was estimated to be the right side of ge locus.