Data from: Nonautosomal genetic variation in carotenoid coloration

Carotenoid-based coloration plays an important role in signaling, is often sexually dimorphic, and is potentially subject to directional and/or sex-specific selection. To understand the evolutionary dynamics of such color traits, it is essential to quantify patterns of inheritance, yet nonautosomal sources of genetic variation are easily overlooked by classical heritability analyses. Carotenoid metabolism has recently been linked to mitochondria, highlighting the potential for color variation to be explained by cytoplasmically inherited factors. In this study, we used quantitative genetic animal models to estimate the importance of mitochondrial and sex chromosome–linked sources of genetic variation in coloration in two songbird populations in which dietary carotenoids are either unmodified (great tit plumage) or metabolized into alternative color forms (zebra finch beak). We found no significant Z-linked genetic variance in great tit plumage coloration, while zebra finch beak coloration exhibited significant W linkage and cytoplasmic inheritance. Our results support cytoplasmic inheritance of color in the zebra finch, a trait based on endogenously metabolized carotenoids, and demonstrate the potential for nonautosomal sources to account for a considerable share of genetic variation in coloration. Although often overlooked, such nonautosomal genetic variation exhibits sex-dependent patterns of inheritance and potentially influences the evolution of sexual dichromatism.

基于类胡萝卜素的体色（Carotenoid-based coloration）在信号传递中发挥关键作用，普遍具有性二态性，且可能受到定向选择及/或性别特异性选择的作用。若要解析这类体色性状的进化动力学，量化其遗传模式是必不可少的研究环节，但经典遗传力分析极易忽略非常染色体来源的遗传变异。类胡萝卜素代谢（Carotenoid metabolism）近期被证实与线粒体存在关联，这提示体色变异或许可通过细胞质遗传因子得到解释。本研究采用定量遗传动物模型，对两个鸣禽种群的体色性状中，线粒体与性染色体连锁来源的遗传变异的重要性进行了估算；这两个种群的膳食类胡萝卜素分别未经修饰（大山雀（great tit）羽色）或被代谢为其他颜色形态（斑胸草雀（zebra finch）喙色）。研究结果显示，大山雀的羽色未检测到显著的Z连锁遗传变异，而斑胸草雀的喙色则表现出显著的W连锁遗传与细胞质遗传特征。本研究结果证实，斑胸草雀体内由内源性代谢类胡萝卜素所形成的体色性状存在细胞质遗传，并表明非常染色体来源的遗传变异可在体色性状的遗传变异中占据相当大的比例。尽管这类非常染色体遗传变异常被忽视，但它们呈现出性别依赖的遗传模式，并可能对性二色性（sexual dichromatism）的进化产生影响。