Changes in epidermal pigmentation are associated with eye defects in humans and other vertebrates. In the rock pigeon (Columba livia), the sex-linked Almond color pattern is characterized by hypopigmentation of epidermal structures. The trait is controlled by the classical Stipper (St) locus, and homozygous (ZStZSt) Almond males often have severe eye defects. Heterozygous (ZStZ+) and hemizygous (ZStW) pigeons do not typically have obvious eye defects, suggesting that higher dosage of the mutant allele is deleterious. Because Almond pigeons have pronounced hypopigmentation in epidermal structures, we hypothesized that they might also have reduced eye pigmentation. Here, we examined pigmentation in the iris, ciliary body, anterior retinal pigmented epithelium (RPE), and posterior RPE in pigeons with and without Almond alleles. We found that pigmentation of anterior segment structures was reduced in birds with at least one Almond allele. However, posterior eye pigmentation was substantially reduced only in homozygous Almond birds. We postulate that the gradient of effects on eye pigmentation is due to the different embryological origins of anterior and posterior eye pigment-producing cells.

中文翻译：

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杏仁羽毛颜色图案与家鸽（哥伦巴利维亚）的眼睛色素沉着缺陷有关

表皮色素沉着的变化与人类和其他脊椎动物的眼缺陷有关。在原鸽（Columba livia）中，与性别相关的杏仁色图案的特征在于表皮结构的色素沉着不足。该性状由经典的Stipper（St）基因座控制，纯合子（ZStZSt）杏仁雄性经常患有严重的眼缺陷。杂合子（ZStZ +）和半合子（ZStW）鸽子通常没有明显的眼睛缺陷，这表明较高剂量的突变等位基因是有害的。由于杏仁鸽在表皮结构中色素沉着明显，因此我们推测它们也可能减少了眼部色素沉着。在这里，我们检查了有和没有杏仁等位基因的鸽子的虹膜，睫状体，视网膜前色素上皮（RPE）和后部RPE中的色素沉着。我们发现具有至少一个杏仁等位基因的鸟类减少了前节结构的色素沉着。但是，仅在纯合子杏仁鸟中，后眼色素沉着的情况明显减少。我们假设对眼睛色素沉着的影响的梯度是由于前眼色素生成细胞和后眼色素生成细胞的胚胎起源不同。