Experiments were undertaken to detect genetic variation for the sex ratio in D. pseudoobscura that is independent of the "sex-ratio" (SR) meiotic drive system. Females inseminated in a natural population produce broods that are heterogeneous with respect to sex ratio. Lines selected for high percentage of male progeny responded in one of two independent artificial selection experiments; the realized heritability was 0.101. Interline crosses between the selected high (percent males) line, low line, and an unselected standard stock reveal a significant male effect, nonsignificant female effect, and marginally significant interaction. Selection gains were rapidly lost when selection was relaxed. Males carrying the SR X-chromosome on a genetic background selected for high percentage of males show no modification of SR meiotic drive. It is suggested that populations are polymorphic for autosomal or X-linked variants that modify the segregation of sex chromosomes and are maintained in a polymorphic state by a balance between segregation and zygotic selection.
|Original language||English (US)|
|Number of pages||5|
|Journal||Journal of Heredity|
|State||Published - 1981|
Bibliographical noteFunding Information:
The author is assistant professor in the Department of Genetics and Cell Biology, University of Minnesota, 1445 Gortner Ave., St. Paul, MN 55108. Research was supported by NIH grants GM-28016 and GM-10452-15. The author is grateful to Dr. Marcus Feldman, for his support during the course of this work, and to Dr. Y. Hiraizumi, for his critical comments on the manuscript. © 1981, American Genetic Association.