A copy number variant is associated with a spectrum of pigmentation patterns in the rock pigeon (Columba livia)
A copy number variant is associated with a spectrum of pigmentation patterns in the rock pigeon (Columba livia)
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DOI：
10.1371/journal.pgen.1008274
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发表时间：
2020-05-01
期刊：
影响因子：
4.5
通讯作者：
Shapiro, Michael D.
中科院分区：
文献类型：
--
作者：
Bruders, Rebecca;Van Hollebeke, Hannah;Shapiro, Michael D.
岩鸽（Columba livia）展示了一系列非同寻常的色素图案变化。其中一种模式，杏仁，其特征是一个杂色拼凑的羽毛颜色，分布在一个明显的随机方式。杏仁是一个性连锁的半显性性状，由经典的Stipper（St）位点控制。杂合雄性（Z（St）Z（+）性染色体）和半合雌性（Z（St）W）因其迷人的羽毛而受到育种者的青睐。与此相反，纯合子雄性杏仁（Z（St）Z（St））发展严重的眼睛缺陷，往往缺乏羽毛色素沉着，这表明更高剂量的突变等位基因是有害的。为了确定杏仁的分子基础，我们比较了杏仁鸽和非杏仁鸽的基因组，并确定了Z染色体上的一个候选St位点。我们发现了一个拷贝数变异（CNV）内的分化区域，捕获完整或部分编码序列的四个基因，包括黑素体成熟基因Mlana。我们没有发现CNV内基因的固定编码变化，但所有的基因都在扁桃鸟的再生羽毛芽领细胞中错误表达。值得注意的是，在St基因座的其他六个等位基因与色素脱失表型相关，并且都表现出相同的CNV扩张。在ST的结构变异与羽毛色素沉着和基因表达的多样性，从而提供了一个潜在的模式，在pige.Author summaryThe负责不同动物的颜色模式的快速表型进化知之甚少，部分原因是缺乏研究生物，都是遗传上听话和表型多样性。家鸽（Columba livia）的许多特征都是经过人工选择的，包括这个单一物种的不同品种内和之间都可变的各种颜色模式。我们调查了一个性连锁的颜色模式的遗传基础，在鸽子称为杏仁，其特点是由一个洒模式的羽毛色素沉着。带有一个杏仁等位基因拷贝的鸽子具有理想的颜色模式;然而，带有两个杏仁突变拷贝的雄性鸽子具有严重的色素缺失和先天性眼睛缺陷。通过比较杏仁鸽和非杏仁鸽的基因组，我们发现杏仁鸽有一个染色体区域的额外拷贝，该区域包含一个对色素颗粒形成至关重要的基因。我们还发现，该区域的不同拷贝数与不同程度的色素减少有关。鸽子中的杏仁表型与狗中的山鸟色毛色突变体有着显著的相似之处，我们对鸽子的新研究结果表明，这两个物种中这些性状的遗传机制相似。我们的工作强调了基因拷贝数变异作为快速表型进化的潜在驱动力的作用。
Rock pigeons (Columba livia) display an extraordinary array of pigment pattern variation. One such pattern, Almond, is characterized by a variegated patchwork of plumage colors that are distributed in an apparently random manner. Almond is a sex-linked, semi-dominant trait controlled by the classical Stipper (St) locus. Heterozygous males (Z(St)Z(+) sex chromosomes) and hemizygous Almond females (Z(St)W) are favored by breeders for their attractive plumage. In contrast, homozygous Almond males (Z(St)Z(St)) develop severe eye defects and often lack plumage pigmentation, suggesting that higher dosage of the mutant allele is deleterious. To determine the molecular basis of Almond, we compared the genomes of Almond pigeons to non-Almond pigeons and identified a candidate St locus on the Z chromosome. We found a copy number variant (CNV) within the differentiated region that captures complete or partial coding sequences of four genes, including the melanosome maturation gene Mlana. We did not find fixed coding changes in genes within the CNV, but all genes are misexpressed in regenerating feather bud collar cells of Almond birds. Notably, six other alleles at the St locus are associated with depigmentation phenotypes, and all exhibit expansion of the same CNV. Structural variation at St is linked to diversity in plumage pigmentation and gene expression, and thus provides a potential mode of rapid phenotypic evolution in pigeons.Author summaryThe genetic changes responsible for different animal color patterns are poorly understood, due in part to a paucity of research organisms that are both genetically tractable and phenotypically diverse. Domestic pigeons (Columba livia) have been artificially selected for many traits, including an enormous variety of color patterns that are variable both within and among different breeds of this single species. We investigated the genetic basis of a sex-linked color pattern in pigeons called Almond that is characterized by a sprinkled pattern of plumage pigmentation. Pigeons with one copy of the Almond allele have desirable color pattern; however, male pigeons with two copies of the Almond mutation have severely depleted pigmentation and congenital eye defects. By comparing the genomes of Almond and non-Almond pigeons, we discovered that Almond pigeons have extra copies of a chromosome region that contains a gene that is critical for the formation of pigment granules. We also found that different numbers of copies of this region are associated with varying degrees of pigment reduction. The Almond phenotype in pigeons bears a remarkable resemblance to Merle coat color mutants in dogs, and our new results from pigeons suggest that similar genetic mechanisms underlie these traits in both species. Our work highlights the role of gene copy number variation as a potential driver of rapid phenotypic evolution.