Møller A P, Mousseau T A
Laboratoire de Parasitologie Evolutive, CNRS UMR 7103, Université Pierre et Marie Curie, 7 quai St. Bernard, Case 237, F-75252 Paris Cedex 05, France.
Evolution. 2003 Sep;57(9):2139-46.
Secondary sexual characters have been hypothesized to be particularly susceptible to the deleterious effects of mutation because the expression of such characters is usually influenced by many more metabolic pathways than are ordinary morphological characters. We tested this hypothesis using the elevated mutation rates in the barn swallow (Hirundo rustica) of the Chernobyl region of Ukraine as a model system. A great deal is known about the relative importance of different characters for male mating success in this species. The importance of phenotypic characters for male mating success was quantified based on a long-term study of a Danish breeding population, by expressing phenotypic differences between mated and unmated males as the difference between log-transformed mean values. For field samples from Ukraine we likewise expressed the difference in male phenotype between individuals living in a relatively uncontaminated area and individuals from the Chernobyl region as the difference between log-transformed mean values. The standardized difference in male phenotype between the two regions in Ukraine for the 41 different characters was strongly positively correlated with the standardized difference in male phenotype between mated and unmated males from Denmark. The standardized difference in male phenotype between the two regions in Ukraine was significantly positively associated with sexual size dimorphism. However, the standardized difference in male phenotype between mated and unmated males was a much better predictor of standardized difference in male phenotype between the two regions in Ukraine than was the standardized difference in sexual size dimorphism, expressed as the difference between log-transformed mean values for males and females. These findings are consistent with the hypothesis that traits most important for sexual selection are particularly susceptible to the effects of deleterious mutations.
有假说认为，次生性征特别容易受到突变有害效应的影响，因为与普通形态特征相比，此类性状的表达通常受更多代谢途径的影响。我们以乌克兰切尔诺贝利地区家燕（Hirundo rustica）的高突变率作为模型系统来检验这一假说。对于该物种中不同特征对雄性交配成功的相对重要性，我们已了解很多。基于对丹麦一个繁殖种群的长期研究，通过将已交配和未交配雄性之间的表型差异表示为对数转换后平均值之间的差异，对表型特征对雄性交配成功的重要性进行了量化。对于来自乌克兰的野外样本，我们同样将生活在相对未受污染地区的个体与切尔诺贝利地区个体之间的雄性表型差异表示为对数转换后平均值之间的差异。乌克兰两个地区在41种不同特征上雄性表型的标准化差异与丹麦已交配和未交配雄性之间雄性表型的标准化差异呈强正相关。乌克兰两个地区之间雄性表型的标准化差异与两性体型差异显著正相关。然而，已交配和未交配雄性之间雄性表型的标准化差异比以雄性和雌性对数转换后平均值之间的差异表示的两性体型差异的标准化差异，能更好地预测乌克兰两个地区之间雄性表型的标准化差异。这些发现与以下假说一致，即对性选择最重要的性状特别容易受到有害突变的影响。
