Artificial selection on a fitness-component in Drosophila melanogaster.

Abstract

The apparent maintenance of significant additive genetic variances for components of fitness is a major puzzle to have come out of recent research on the quantitative genetics of fitness. This issue was addressed by means of artificial selection for increased early fecundity in a Drosophila melanogaster population which had been maintained under stable conditions for >100 generations. An initial direct response to artificial selection indicated that this population could be maintaining the genetic variability for fecundity which had been detected earlier by means of sib analysis, but the response was not sustained in later generations. Crossing selected with selected lines and control with control lines resulted in the recovery of the initial response to artificial selection, suggesting that inbreeding may have had significant effects. Results of selection-relaxation provided no evidence of natural selection acting to erase the gains achieved by artificial selection.-from Author