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|