A multivariate view of the evolution of sexual dimorphism
A multivariate view of the evolution of sexual dimorphism
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性二态性进化的多元观点
DOI：
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发表时间：
2013
影响因子：
2.1
通讯作者：
L. Rowe
中科院分区：
文献类型：
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作者：
Minyoung J. Wyman;J. Stinchcombe;L. Rowe
性别差异往往是戏剧性的和广泛的分类群。它们的奢侈和普遍存在可能令人困惑，因为男性和女性共同的潜在基因组预计会阻碍而不是促进表型分化。尽管有着共同的基因组，但两性异形现象的普遍存在可能更容易通过考虑多变量而不是单变量来解释，这是控制两性异形进化的框架。在单变量公式中，遗传方差的差异和低的性间遗传相关（rMF）可以促进性二型性的进化。然而，分析遗传力或遗传方差的性别特异性差异的研究并不总是发现显著差异。此外，许多报告的风险管理系数估计值非常高，而且是正数。当单态遗传力和高rMF同时存在时，在逐性状基础上的性二态性的进化受到严重限制。相比之下，多元公式具有更大的通用性和更大的灵活性。虽然多变量性二态性研究的数量很少，但几乎所有的研究都支持G（方差-协方差）矩阵中的性别特异性差异; G矩阵在大小和/或方向上可能不同，从而影响性别之间对选择的反应。第二，而正值的单变量量rMF只阻碍性二态性的积极变化，积极的协方差的性间协方差B矩阵可以帮助或阻碍。同样，少数报告B矩阵的研究表明，它通常是不对称的，因此B可以影响两性之间不同的单一性状的进化。与单变量方法相比，多变量方法通常表明性状之间的遗传协方差可以强烈地约束性状进化。相比之下，在两性异形的进化中，通过考虑性别特异性选择对性别特异性G矩阵和不对称B矩阵的影响，多元观点可能揭示出两性异形进化的更多机会。
Sexual differences are often dramatic and widespread across taxa. Their extravagance and ubiquity can be puzzling because the common underlying genome of males and females is expected to impede rather than foster phenotypic divergence. Widespread dimorphism, despite a shared genome, may be more readily explained by considering the multivariate, rather than univariate, framework governing the evolution of sexual dimorphism. In the univariate formulation, differences in genetic variances and a low intersexual genetic correlation ( rMF ) can facilitate the evolution of sexual dimorphism. However, studies that have analysed sex‐specific differences in heritabilities or genetic variances do not always find significant differences. Furthermore, many of the reported estimates of rMF are very high and positive. When monomorphic heritabilities and a high rMF are present together, the evolution of sexual dimorphism on a trait‐by‐trait basis is severely constrained. By contrast, the multivariate formulation has greater generality and more flexibility. Although the number of multivariate sexual dimorphism studies is low, almost all support sex‐specific differences in the G (variance‐covariance) matrix; G matrices can differ with respect to size and/or orientation, affecting the response to selection differently between the sexes. Second, whereas positive values of the univariate quantity rMF only hinder positive changes in sexual dimorphism, positive covariances in the intersexual covariance B matrix can either help or hinder. Similarly, the handful of studies reporting B matrices indicate that it is often asymmetric, so that B can affect the evolution of single traits differently between the sexes. Multivariate approaches typically demonstrate that genetic covariances among traits can strongly constrain trait evolution when compared with univariate approaches. By contrast, in the evolution of sexual dimorphism, a multivariate view potentially reveals more opportunities for sexual dimorphism to evolve by considering the effect sex‐specific selection has on sex‐specific G matrices and an asymmetric B matrix.