Genetic characterization of the mei-41 locus in Drosophila melanogaster.

The mutagen-sensitive mutant mus(1) 104D1 of Drosophila melanogaster maps to a position on the X chromosome very close to the meiotic mutant mei-41D5. Both mutants have been characterized as mutagen-sensitive and defective in post-replication repair. In the present report we show by complementation studies that mus(1) 104 and mus(1) 103 are allelic with mei-41. In addition, two reported alleles of mus(1) 104 lie between the mei-41 alleles A10 and D5. The size of the mei-41 locus is estimated to be about 0.1 centimorgans (cM). Because several alleles of mei-41 have been shown to reduce recombination and increase meiotic chromosome loss and nondisjunction, mus(1) 104D1 females were examined for defects in meiosis. Although there was no evidence for reduced recombination on the second chromosome in homozygous mus(1) 104D1 females, heterozygous mus(1) 104D1/mei-41D5 and mus(1) 104D1/deficiency females showed reduced levels of recombination. However, there was no evidence of an increase in nondisjunction in these females.