Ingleby F C, Innocenti P, Rundle H D, Morrow E H
Evolution, Behaviour and Environment Group, School of Life Sciences, University of Sussex, John Maynard Smith Building, Falmer, Brighton, UK.
J Evol Biol. 2014 Aug;27(8):1721-32. doi: 10.1111/jeb.12429. Epub 2014 Jun 3.
Males and females share much of their genome, and as a result, intralocus sexual conflict is generated when selection on a shared trait differs between the sexes. This conflict can be partially or entirely resolved via the evolution of sex-specific genetic variation that allows each sex to approach, or possibly achieve, its optimum phenotype, thereby generating sexual dimorphism. However, shared genetic variation between the sexes can impose constraints on the independent expression of a shared trait in males and females, hindering the evolution of sexual dimorphism. Here, we examine genetic constraints on the evolution of sexual dimorphism in Drosophila melanogaster cuticular hydrocarbon (CHC) expression. We use the extended G matrix, which includes the between-sex genetic covariances that constitute the B matrix, to compare genetic constraints on two sets of CHC traits that differ in the extent of their sexual dimorphism. We find significant genetic constraints on the evolution of further dimorphism in the least dimorphic traits, but no such constraints for the most dimorphic traits. We also show that the genetic constraints on the least dimorphic CHCs are asymmetrical between the sexes. Our results suggest that there is evidence both for resolved and ongoing sexual conflict in D. melanogaster CHC profiles.
雄性和雌性共享大部分基因组，因此，当对一个共享性状的选择在两性之间存在差异时，就会产生基因座内的性冲突。这种冲突可以通过性别特异性遗传变异的进化得到部分或完全解决，这种变异使每个性别都能接近或可能达到其最佳表型，从而产生两性异形。然而，两性之间的共享遗传变异可能会对共享性状在雄性和雌性中的独立表达施加限制，阻碍两性异形的进化。在这里，我们研究了黑腹果蝇表皮碳氢化合物（CHC）表达中两性异形进化的遗传限制。我们使用扩展的G矩阵，其中包括构成B矩阵的两性之间的遗传协方差，来比较对两组两性异形程度不同的CHC性状的遗传限制。我们发现，对于最不具两性异形的性状，进一步异形进化存在显著的遗传限制，但对于最具两性异形的性状则没有这种限制。我们还表明，对最不具两性异形的CHC的遗传限制在两性之间是不对称的。我们的结果表明，有证据表明黑腹果蝇CHC谱中存在已解决的和正在进行的性冲突。
