AN INVESTIGATION OF THE GENETICS OF "MALE SEX-RATIO" PHENOTYPE IN DROSOPHILA PSEUDOOBSCURA

1 Department of Biology, University of Louisville, Louisville, Kentucky 40292

A laboratory strain of Drosophila pseudoobscura (L116) is studied that, when crossed to sex-ratio homozygous females, produces sons that exhibit varying levels of the male sex-ratio (msr) phenotype. The msr phenotype occurs only in sex-ratio males and is due to the production of a high frequency of nullo-XY sperm. The level of the msr phenotype is variable, and new variability is generated in one father-son transmission. Pedigree studies indicate the genes for msr reside on the Y chromosome or the autosomes of the L116 stock.

Submitted on May 27, 1985
Accepted on February 28, 1986