Mitotic recombination inMusca domesticaL. and its influence on mosaicism, gynandromorphism and recombination in males

Abstract

In the housefly, mosaics appear spontaneously but rarely. Sexual mosaics or gynandromorphs also appear in strains in which sex determination is based on autosomal sex factors. Rare cases of recombination in the male have been reported by some authors. In field and laboratory populations, mitotic plates with figures indicating exchange of chromatid segments are regularly observed in tissues of individuals of both sexes and at all stages of development. All these anomalies are interpreted as outward manifestation of the same phenomenon: mitotic recombination. The cytological basis of mitotic recombination, its relative frequency, its influence on linkage and genetic variability are discussed.

Distribution of heterochromatin on the mitotic chromosomes of Musca domestica L. in relation to the activity of male-determining factors

“…Mitotic chromosomes were recovered from gonads of adult males and stained with orcein (Rubini et al 1980). The C-banding technique was described by El Agoze et al (1992).…”

Inheritance patterns of new genetic markers and occurrence of spontaneous mosaicism in the monogenic blowfly Chrysomya rufifacies(Diptera: Calliphoridae)

“…Chiasma-like structures had been detected in all three large chromosomes of D. melanogaster at mitotic pro-and metaphase stages (Kaufmann 1934;Cooper 1948); however, it remained uncertain whether they represented the cytological counterpart of mitotic recombination. Recently, similar chiasma-like configurations, which were considered to represent mitotic recombination events, have also been found in mitotic cells of various tissues and in all stages of development in M. domestica (Rubini et al 1980). The observation of chromatid exchange during neuroblast division in P. terrae-novae, which is closely related to C. rufifacies, might be considered to imply the possibility of spontaneous mitotic recombination in calliphorids.…”

“…Such mechanisms have been detected in several insect species, especially in Drosophila (see Hall et al 1976, Ashburner 1989, as well as in mammals (see McLaren 1978, Favor andNeuha¨user-Klaus 1994). Among Diptera mitotic recombination is well known from Drosophila melanogaster (for review see Becker 1976;Graf 1995) and from the housefly Musca domestica (No¨thiger and Du¨bendorfer 1971;Rubini et al 1980;Hilfiker-Kleiner et al 1993). In both species mosaics similar to those found in C. rufifacies have been obtained.…”

Gametic selection affecting sex‐ratio in housefly(Musca domesticaL.)

“…Because of the rarity (Milani, 1956;Rubini et al, 1980;Hiroyoshi et al, 1982) of crossing-over in the male, recessive markers are expected to segregate in opposition to the male sex when marker(s) and M belong to homologous autosomes. Thus, when marker bwb on autosome 3 and M m are involved, all females are bwb/bwb and all males are bwb/bwb* (Milani et al, 1967).…”