Sex and Selection for A Quantitative Character in Drosophila. I.Single-Sex Selection

Abstract

SummarySelection for abdominal bristle number was done in six lines, three with selection in females only and three in males only_ Selection was equally effective (for a given selection differential) when carried out in either sex, even though more than one-third of the additive genetic variation was sex linked_ Most response in a given sex was found in the treatment selected in that sex. Relaxed lines failed to show fluctuating scores in the two sexes as predicted by Griffing (1965). Epistatic decay may have masked these effects.Formulae to predict response to selection, when there is a scale difference between the sexes and the genetic correlation between sexes is less than unity, are presented. Predictions of the relative response in males and females from these formulae were in good agreement with observed response in the single-sex abdominal bristle selection lines and in the abdominal bristle selection lines of Jones, Frankham, and Barker (1968).

Constraints on the evolution of attractive traits: genetic (co)variance of zebra finch bill colour

“…In this same experiment, there was significant opposing selection on male and female bill colour that is consistent with zebra finch bill colour being displaced from sex-specific optima (Price, 1991). In other species, estimates of genetic correlations between the sexes have also been very high for morphological characters (Harrison, 1953;Frankham, 1968aFrankham, , 1968bCrowley & Atchley, 1986;Crowley et al, 1986;Rogers & Mukherjee, 1992). Therefore, genetic covariances between traits expressed in males and females may cause traits to be displaced from their sex-specific optima in other species for evolutionarily long time periods (Lande, 1 980a).…”

“…Genetic covariances between the sexes have been reported for various morphological traits in mice (Eisen & Legates, 1966;Eisen & Hanrahan, 1972), friut flies (Harrison, 1953;Frankham, 1968aFrankham, , 1968bCrowley et at., 1986;Crowley & Atchley, 1988) and humans (Rogers & Mukherjee, 1992). The occurrence of relatively large genetic covariances between the sexes in these animals indicate that the selective pressures in one sex would have a large effect on the other sex and thus the evolution to sex-specific optima may proceed very slowly (Lande, 1980a;Lande & Arnold, 1985).…”

Selection for Sexual Dimorphism in Body Weight of Mice

“…Selection for sexual dimorphism has been moderately successful for abdominal bristle number in Drosophila melanogaster (Harrison 1953;Frankham 1968b) and body weight in mice (Korkman 1957). Frankham (1968a) found that single-sex selection changed the sexual dimorphism for abdominal bristle number in D. melanogaster since selection response was consistently greater in the selected sex.…”

“…Frankham (1968aFrankham ( , 1968b defined the sex dimorphism ratio as male mean/female mean and stated that it should be free of scale effects. Although the ratio is only scale-free under certain restrictive assumptions, it is reported here for comparative purposes since Korkman (1957) o Replicate I (Mfl-mfl).…”

“…Theoretical developments indicate that selection response may be influenced by the genetic variance in sexual dimorphism (Becker, Sinha, and Bogyo 1964;Griffing 1966;Eisen and Legates 1966;Frankham 1968a). Rahnefeld et al (1963) and Eisen and Legates (1966) have suggested that the genetic correlation between the sexes for post-weaning growth rate in mice was less than unity.…”