TEMPERATURE-SENSITIVE MUTATIONS IN DROSOPHILA MELANOGASTER. IX. DOMINANT COLD-SENSITIVE LETHALS ON THE AUTOSOMES

Raja Rosenbluth ¹, Dean Ezell ¹, and David T. Suzuki ¹

¹ Department of Zoology, The University of British Columbia, Vancouver, B.C., Canada

Ethyl methanesulfonate-treated autosomes were screened for the presence of dominant cold-sensitive (DCS) lethal mutations in Drosophila melanogaster. None was found among 6,552 treated and 168 untreated third chromosomes. Twenty-three DCS-L chromosomes which caused death at 17°C but survived at 22°C and 29°C were recovered from 5,046 mutagenized chromosome 2's.—The DCS-L mutations all mapped around dp and appeared to be functionally allelic. Lethality of heterozygotes for most of the DCS-L's occurred over a prolonged interval from the embryonic through the larval instars. Prolonged incubation at 17°C did not demonstrate any maternal effect on zygotic survival.