Candidate gene analysis suggests untapped genetic complexity in melanin-based pigmentation in birds

Studies on melanin-based color variation in a context of natural selection have provided a wealth of information on the link between phenotypic and genetic variation. Here, we evaluated associations between melanic plumage patterns and genetic polymorphism in the Réunion grey white-eye (Zosterops borbonicus), a species in which mutations on MC1R do not seem to play any role in explaining melanic variation. This species exhibits five plumage color variants that can be grouped into three color forms which occupy discrete geographic regions in the lowlands of Réunion and a fourth form which comprises two color morphs (grey and brown), occurs at high elevation, and represents a true color polymorphism. We conducted a comprehensive survey of sequence variation in 96 individuals at a series of seven candidate genes other than MC1R that have been previously shown to influence melanin-based color patterns in vertebrates, including genes that have rarely been studied in a wild bird species befor...针对自然选择背景下基于黑色素的体色变异的相关研究，已为表型变异与遗传变异之间的关联积累了大量详实数据。本研究以留尼旺灰绣眼鸟（Zosterops borbonicus）为研究对象，评估其深色羽色模式与遗传多态性之间的关联；该物种的黑皮质素1受体（MC1R）突变似乎无法解释其深色体色变异现象。该物种共存在5种羽色变异类型，可划分为3个色型，分别占据留尼旺岛低地的互不重叠的地理区域；另有第4个色型包含灰色与棕色2种羽色态，栖息于高海拔区域，属于典型的体色多态类群。我们对96个个体的7个非MC1R候选基因的序列变异开展了全面检测；这些基因此前已被证实可影响脊椎动物的基于黑色素的体色模式，其中不乏此前极少在野生鸟类中被研究的基因……