THE MECHANISM OF A BROODING EFFECT ASSOCIATED WITH SEGREGATION DISTORTION IN DROSOPHILA MELANOGASTER

1 Department of Genetics and Cell Biology, University of Minnesota, Saint Paul, Minnesota 55101

The recovery of the SD chromosome from a heterozygous SD male increases with brood. This is independent of the age of the female, occurs during the time the sperm are stored in the females, disappears when the segregation distortion is suppressed, and is temperature-sensitive—temperature shocks above or below 25°C applied to the mature sperm both tend to accelerate the increase in the recovery of SD. All this suggests the existence of a class of sperm affected by SD in which the sperm are able to fertilize eggs for a short time following ejaculation but become dysfunctional thereafter.

Submitted on October 31, 1972
Revised on April 30, 1973