[Temperature-sensitive autosomal dominant lethal mutations in Drosophila melanogaster induced by ethylmethane sulfonate].

Cold- and heat-sensitive dominant autosome and recessive sex-linked lethals were scored using C(1)RM, y; vg bw; e ss tester stock. The frequencies of heat-sensitive mutations were 1.43, 0.30, 0.07% and of cold-sensitive ones were 0.39, 0.16 and 0.09% in the 1-st, 2-nd and 3-rd chromosomes, respectively. For the first time, dominant cold-sensitive lethals were obtained in chromosome 3. The data from genetic analysis point to the fact that penetrance of such mutations strongly depends on the genetic background. That may be the reason, why they were not obtained using some of the balancer-3 chromosomes. Also, "cryptic" dominant autosome mutants were found which were not conditional but only revealed in the F2 generation. Their possible origin as gonado-somatic mosaics is discussed.