Inheritance of cytogenetic and new genetic markers in Megasella scalaris, a fly with an unusual sex determining mechanism

Abstract

Megaselia scalaris has a karyotype of two metaccntric chromosome pairs, indistinguishable from one another, and an acrocentric chromosome pair. All three pairs can carry the male determining factor (Mainx, 1966;Tokunaga, 1955b). Seven cytogenetic markers, translocations T1-T7, and three new genetic markers, ge, By and sh, were isolated and characterized during this study. The translocations involved two or all three chromosomes of a haploid chromosome set. All translocations recovered were male specific, transmitted from father to all sons. This allowed us to locate the male determining factor, M, on one of the two metacentric chromosomes in our strain 'Wien'. By crossing the new gene mutants with the cytogenetic markers, the autosomal mutants ge and By could be located to the acrocentric chromosome, and the partially sex-linked mutant sh to a metacentric. The results are intended to serve as a framework to fit in molecular markers.

Rearing the scuttle flyMegaselia scalaris(Diptera: Phoridae) on industrial compounds: implications on size and lifespan

“…For each condition 4 females and 2 males M. scalaris ‘Wien’ strain (Mainx, 1964; Johnson, Mertl & Traut, 1988) were transferred into a tube containing the test food source and allowed to mate. A total of 20 replicates for each condition were made.…”

New Y chromosomes and early stages of sex chromosome differentiation: sex determination in Megaselia

“…Seven translocations were transmitted in the male line only, a characteristic of Y chromosomes. They were reciprocal translocations between two or all three chromosomes, t(1; 2 Y ), t(2 Y ; 3) or t(1; 2 Y ; 3), and identified the Y chromosome as a chromosome 2 (Johnson et al 1988;.…”

“…The three chromosome pairs were labelled cytogenetically with X rayinduced translocations but could not safely be assigned to the formel linkage groups because all previously isolated phenotypic marker strains had been lost. A few phenotypic markers were newly isolated and mapped to the respective chromosomes in crosses with translocations strains (Johnson et al 1988;Traut et al 1994). But only one, ge from chromosome 3, was a 'good' marker, i.e.…”

Analysis of centromere structure in the fly Megaselia scalaris (Phoridae, Diptera) using CREST sera, anti‐histone antibodies, and a repetitive DNA probe

“…The flies, M scalaris strain 'Wien', were kept in plastic pots (diameter ca 10 cm, height ca 9 cm, Nalge Company, Rochester, NY) sealed with foam plugs. The rearing conditions and the medium composition have been described previously [27].…”

“…The reason for the stability of the CLEs probably lies in the fact that they pair in meiosis [67]. The regular karyotype of M scalaris consists of two metacentric and one telocentric chromosome pair [27].…”