Meagher Thomas R
Department of Biological Sciences, Rutgers University, P.O. Box 1059, Piscataway, New Jersey, 08855-1059.
Evolution. 1994 Aug;48(4):939-951. doi: 10.1111/j.1558-5646.1994.tb05284.x.
A well-established theoretical relationship exists between genetic correlations between the sexes and the dynamics of response to sex-specific selection. The present study investigates the response to sex-specific selection for two sexually dimorphic traits that have been documented to be genetically variable, calyx diameter and flower number, in Silene latifolia. Following the establishment of a base generation with a known genetic background, selection lines were established and two generations of sex-specific selection were imposed. Calyx diameter responded directly to sex-specific selection, and the positive genetic correlation between the sexes was reflected in correlated responses in the sex that was not the basis for selection within a particular line. Flower number showed a more erratic response to sex-specific selection in that selection in some lines was initially in the wrong direction, that is, selection for a decrease in flower number resulted in an increase. These erratic responses were attributable to genotype-environment interaction as reflected in significant heteroscedasticity in variance among families. Correlated responses to selection in the sex that was not the immediate basis for selection indicated the possible existence of a negative genetic correlation between the sexes for this trait. These results test for the first time the impact of genetic correlations between the sexes on the evolutionary dynamics of sexually dimorphic traits in a plant species.
性别间的遗传相关性与对性别特异性选择的响应动态之间存在着一种已确立的理论关系。本研究调查了对两种已被证明具有遗传变异性的两性异形性状——萼片直径和花数——的性别特异性选择的响应，该研究以宽叶蝇子草为对象。在建立了具有已知遗传背景的基础世代之后，建立了选择系，并进行了两代性别特异性选择。萼片直径直接响应性别特异性选择，性别间的正遗传相关性体现在特定品系内非选择基础性别的相关响应中。花数对性别特异性选择的响应更为不稳定，因为在某些品系中，最初的选择方向是错误的，也就是说，选择减少花数却导致了花数增加。这些不稳定的响应归因于基因型 - 环境相互作用，这在各家族间方差的显著异方差性中得到体现。对非直接选择基础性别的选择的相关响应表明，该性状的性别间可能存在负遗传相关性。这些结果首次检验了性别间的遗传相关性对植物物种两性异形性状进化动态的影响。
