COMPLEMENTATION ANALYSIS OF METHYL METHANE-SULFONATE-INDUCED RECESSIVE LETHAL MUTATIONS IN THE ZESTE-WHITE REGION OF THE X CHROMOSOME OF DROSOPHILA MELANOGASTER

C. P. Liu ¹ and J. K. Lim ¹

¹ Department of Biology, University of Wisconsin—Eau Claire, Eau Claire, Wisconsin 54701

Recessive lethal mutations in the 3A1 to 3C2 region of the X chromosome of Drosophila melanogaster were detected in 113 of 33,544 sperm treated by feeding 5 mM methyl methanesulfonate in 1% sucrose for 22 hours. Seven of the 113 lethals were sterile, leaving 106 for analysis by complementation tests. With only one exception, these mutants were found to have lesions restricted to single loci. One of these single-site mutations was in gt, 2 in tko, 18 in zw-1, 12 in zw-8, 6 in zw-4, 3 in zw-10, 3 in zw-13, 21 in zw-2, 7 in zw-3, 5 in zw-6, 6 in zw-12, 1 in zw-7, 12 in zw-5, 5 in zw-11, and 3 in zw-9, One of the lethals, m69, was non-complementary to two adjacent loci, zw-2 and zw-3, possibly indicating a deletion encompassing two loci. The results confirm that there are at least 15 recessive lethal loci in the region and are consistent with the hypothesis of Lim and Snyder (1968 and 1974) that inability of monofunctional alkylating chemicals to induce deletion-associated mutations is a characteristic of the compounds.