Tringali Angela, Bowman Reed, Husby Arild
Avian Ecology Laboratory Archbold Biological Station 123 Main Dr. Venus Florida 33960.
Department of Biosciences University of Helsinki PO Box 65 FI-00014 Helsinki Finland.
Ecol Evol. 2015 Nov 2;5(22):5413-5422. doi: 10.1002/ece3.1793. eCollection 2015 Nov.
Sexually dimorphic plumage coloration is widespread in birds and is generally thought to be a result of sexual selection for more ornamented males. Although many studies find an association between coloration and fitness related traits, few of these simultaneously examine selection and inheritance. Theory predicts that sex-linked genetic variation can facilitate the evolution of dimorphism, and some empirical work supports this, but we still know very little about the extent of sex linkage of sexually dimorphic traits. We used a longitudinal study on juvenile Florida scrub-jays () to estimate strength of selection and autosomal and Z-linked heritability of mean brightness, UV chroma, and hue. Although plumage coloration signals dominance in juveniles, there was no indication that plumage coloration was related to whether or not an individual bred or its lifetime reproductive success. While mean brightness and UV chroma are moderately heritable, hue is not. There was no evidence for sex-linked inheritance of any trait with most of the variation explained by maternal effects. The genetic correlation between the sexes was high and not significantly different from unity. These results indicate that evolution of sexual dimorphism in this species is constrained by low sex-linked heritability and high intersexual genetic correlation.
两性异形的羽毛颜色在鸟类中很普遍，通常被认为是对更具装饰性的雄性进行性选择的结果。尽管许多研究发现颜色与适应性相关特征之间存在关联，但其中很少有同时考察选择和遗传的。理论预测，性连锁遗传变异可以促进两性异形的进化，一些实证研究也支持这一点，但我们对两性异形特征的性连锁程度仍然知之甚少。我们对佛罗里达灌丛鸦幼鸟进行了一项纵向研究，以估计平均亮度、紫外色度和色调的选择强度以及常染色体和Z染色体遗传力。尽管羽毛颜色在幼鸟中表示优势地位，但没有迹象表明羽毛颜色与个体是否繁殖或其终生繁殖成功率有关。虽然平均亮度和紫外色度具有中等遗传力，但色调不具有。没有证据表明任何性状存在性连锁遗传，大部分变异由母体效应解释。两性之间的遗传相关性很高，且与一致性没有显著差异。这些结果表明，该物种两性异形的进化受到低性连锁遗传力和高两性间遗传相关性的限制。
