Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.
Science. 2016 Apr 22;352(6284):470-4. doi: 10.1126/science.aad8786.
Ecological character displacement is a process of morphological divergence that reduces competition for limited resources. We used genomic analysis to investigate the genetic basis of a documented character displacement event in Darwin's finches on Daphne Major in the Galápagos Islands: The medium ground finch diverged from its competitor, the large ground finch, during a severe drought. We discovered a genomic region containing the HMGA2 gene that varies systematically among Darwin's finch species with different beak sizes. Two haplotypes that diverged early in the radiation were involved in the character displacement event: Genotypes associated with large beak size were at a strong selective disadvantage in medium ground finches (selection coefficient s = 0.59). Thus, a major locus has apparently facilitated a rapid ecological diversification in the adaptive radiation of Darwin's finches.
生态特征替代是一种形态趋异的过程，可减少对有限资源的竞争。我们使用基因组分析来研究达尔文雀在加拉帕戈斯群岛的达夫尼主要岛上发生的有案可查的特征替代事件的遗传基础：中型地雀在严重干旱期间与其竞争对手大地雀发生了分化。我们发现了一个包含 HMGA2 基因的基因组区域，该基因在具有不同喙大小的达尔文雀物种中存在系统差异。在辐射中早期分化的两个单倍型参与了特征替代事件：与大喙大小相关的基因型在地雀中处于强烈的选择劣势（选择系数 s = 0.59）。因此，一个主要基因座显然促进了达尔文雀适应性辐射中的快速生态多样化。
