Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08544, USA.
Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, 02912, USA.
Nat Commun. 2018 Nov 19;9(1):4855. doi: 10.1038/s41467-018-07374-9.
Pyrenestes finches are unique among birds in showing a non-sex-determined polymorphism in bill size and are considered a textbook example of disruptive selection. Morphs breed randomly with respect to bill size, and differ in diet and feeding performance relative to seed hardness. Previous breeding experiments are consistent with the polymorphism being controlled by a single genetic factor. Here, we use genome-wide pooled sequencing to explore the underlying genetic basis of bill morphology and identify a single candidate region. Targeted resequencing reveals extensive linkage disequilibrium across a 300 Kb region containing the insulin-like growth factor 1 (IGF1) gene, with a single 5-million-year-old haplotype associating with phenotypic dominance of the large-billed morph. We find no genetic similarities controlling bill size in the well-studied Darwin's finches (Geospiza). Our results show how a single genetic factor may control bill size and provide a foundation for future studies to examine this phenomenon within and among avian species.
金翅雀形目雀科的 Pyrénestes 雀在鸟类中表现出非性别决定的喙大小多态性，被认为是离散选择的典型范例。形态与喙大小随机繁殖，在饮食和相对于种子硬度的摄食表现上存在差异。先前的繁殖实验表明，这种多态性是由单一遗传因素控制的。在这里，我们使用全基因组 pooled 测序来探索喙形态的潜在遗传基础，并确定了一个单一的候选区域。靶向重测序揭示了一个包含胰岛素样生长因子 1 (IGF1) 基因的 300kb 区域内广泛的连锁不平衡，一个单一的 500 万岁的单倍型与大型喙形态的表型优势相关。我们没有发现控制达尔文雀科（Geospiza）中喙大小的遗传相似性。我们的结果表明，单一的遗传因素如何控制喙的大小，并为未来的研究提供了一个基础，以检查这一现象在鸟类物种内部和之间的存在情况。
