Inheritance of Ddt Resistance in a Laboratory Colony of the Housefly, Musca Domestica

Abstract

SummaryStrains of the housefly MUBOO domeatica L., derived by selection from the Canberra laboratory colony established in 1939, were examined genetically and cytologically to determine their composition, in respect to resistance to DDT, and the modes of sex determination and inheritance of this resistance.DDT resistance was found to be determined by an incompletely dominant allele of a gene in chromosome II that confers the ability to metabolize DDT to DDE. In flies of the normal karyotype, 2n = 12: XX females and XY males, resistance is inherited independently of sex, but in atypical XX males, lacking the Y -chromosome, the male determinant is linked with presumably the same resistance allele in one of the chromosome II homologues. The resistance gene in this homologue is thus obligatory for, and confined to, atypical males, but on rare occasions is inherited by a female, indicating that the linkage with the male determinant is not completely stable.Atypical males were not detected in the unselected colony. They were brought into prominence by selection either for early adult emergence or for DDT resistance. Under DDT selection pressure, the progression of one strain towards homozygosity for the resistance allele was retarded slightly by the complete replacement of XY males by the atypical XX type, and the strain was still heterogeneous after 200 generations of selection.Each of 10 lines propagated from single homozygous resistant pairs became heterogeneous when mass-reared in the absence of DDT. Instability of the resistance gene may therefore have been a factor opposing selection in the strain under DDT pressure.Rare XXY males and XXX females among flies of the normal karyotype, and rarer XO and XXX males among the XX males of atypical strains, were considered to be products of non-disjunctions. No XO females were found.

Are autosomal sex-determining factors of the housefly (Musca domestica) spreading north?

“…Also, in a number of resistant populations autosomal M males have been found (Tsukamoto, 1983) and one laboratory experiment showed replacement of standard XY males by autosomal M males after several generations of selection for DDT resistance (Kerr, 1970). However, even though linkage with insecticide resistance genes could facilitate spread of autosomal M factors, it is not clear how it could contribute to the clinal distribution of SD factors in the housefly.…”

“…It has also been proposed that autosomal M factors have spread due to their linkage with insecticide resistance genes (Kerr, 1970;Franco et al, 1982), since the isolation of autosomal M factors coincided with the appearance of insecticide resistance in natural populations of the housefly (Tomita & Wada, 1989b). Also, in a number of resistant populations autosomal M males have been found (Tsukamoto, 1983) and one laboratory experiment showed replacement of standard XY males by autosomal M males after several generations of selection for DDT resistance (Kerr, 1970).…”

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

“…However, karyological analyses of males have failed to detect any translocated Y material in many AM strains (Hiroyoshi 1964;Wagoner 1969;Kerr 1970;Tsukamoto, Shono and Horio 1980). Hiroyoshi (1964) thus argued that the translocated Y material is too small to be visualized by the conventional cytological technique.…”

Sex-determinants and their distribution in various populations ofMusca domesticaL. of Western Europe

“…Since 1958, cases of sex-limited inheritance, interpreted a posteriori as due to autosomal sex-determinants, have been described in several strains of houseflies of non-European origin (Sullivan, 1958;Milani & Franco, 1959a;Kerr, 1960Kerr, ,1961 M II, JUT III, M V, F, Australian laboratory strain (Wagoner, 1969); Mil, Australian DDT-resistant laboratory strains (Kerr, 1970); Mill, North American field populations (McDonald et al 1975); M III, F, Japanese field populations Fukumori, 1977, 1978); FIV, compound laboratory strain (North American-Australian), (McDonald et al 1978); Ml, Mil, Mill, F, Fijian field population (Hiroyoshi & Inoue, 1979); M I, MII, M III, M V, Japanese field populations (Tsukamoto, Shono & Horio, 1980). In Europe only two autosomal sex-determinants have been reported: M III, Czeck DDT-resistant laboratory strains (Rupes & Pinterova, 1975); F (probably polygenic), North Italian field population (Rubini, van Heemert & Franco, 1977).…”