The genetic basis of sexual dimorphism in birds
The genetic basis of sexual dimorphism in birds
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DOI：
10.1111/j.1558-5646.2007.00254.x
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发表时间：
2008-01-01
期刊：
影响因子：
3.3
通讯作者：
Pruett-Jones, Stephen
中科院分区：
文献类型：
--
作者：
Coyne, Jerry A.;Kay, Emily H.;Pruett-Jones, Stephen
性别二态性的遗传基础是进化遗传学中一个有趣的问题，因为二态性特征仅限于一种性别。这些特征可以通过两种方式在遗传上产生。首先，引起二态性的等位基因在第一次出现时可能仅限于一种性别的表达。或者，二态性等位基因最初可以在两种性别中表达，但随后通过修饰基因或调节元件的进化而仅在一种性别中被抑制或促进。我们通过寻找雄性表现出不同类型装饰物的鸟类之间雌性杂交种的性二态性特征的表达来研究这些替代方案。如果涉及性别限制性状的修饰等位基因或调控元件不完全占主导地位，那么这种修饰应该在雌性杂种中分解，然后可能表现出类似于雄性的二态性特征。在检查的 13 个种间杂交中，我们没有发现雌性杂种中存在雄性限制性装饰的表达。这表明雄性饰物从一开始就受到性别限制，或者这些特征通过显性修饰因子（可能是顺式显性调节元件）的进化而变得受到性别限制。观察杂交表型是研究二态性状的遗传学和进化的有用方法。
The genetic basis of sexual dimorphisms is an intriguing problem of evolutionary genetics because dimorphic traits are limited to one sex. Such traits can arise genetically in two ways. First, the alleles that cause dimorphisms could be limited in expression to only one sex at their first appearance. Alternatively, dimorphism alleles could initially be expressed in both sexes, but subsequently be repressed or promoted in only one sex by the evolution of modifier genes or regulatory elements. We investigated these alternatives by looking for the expression of sexually dimorphic traits in female hybrids between bird species whose males show different types of ornaments. If modifier alleles or regulatory elements involved in sex-limited traits are not completely dominant, the modification should break down in female hybrids, which might then show dimorphic traits resembling those seen in males. Of 13 interspecific hybridizations examined, we found not a single instance of the expression of male-limited ornaments in female hybrids. This suggests that male ornaments were sex limited from the outset or that those traits became sex limited through the evolution of dominant modifiers-possibly cis-dominant regulatory elements. Observing hybrid phenotypes is a useful approach to studying the genetics and evolution of dimorphic traits.