Delmore Kira E, Toews David P L, Germain Ryan R, Owens Gregory L, Irwin Darren E
Biodiversity Research Center, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Biodiversity Research Center, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Curr Biol. 2016 Aug 22;26(16):2167-73. doi: 10.1016/j.cub.2016.06.015. Epub 2016 Jul 28.
Details on the genetics of behavioral and quantitative phenotypes remain limited to a few organisms. Such information is central to understanding both adaptation and speciation, as many of these phenotypes reduce gene flow between taxa [1-3]. Hybrid zones provide an ideal arena for studying this topic, as they consist of recombinant genotypes that allow genetic mapping of traits distinguishing natural populations [4]. We examined the genetic basis of migratory orientation and plumage color, both of which may contribute to speciation, in a hybrid zone between two groups of Swainson's thrushes that differ in these traits. We identified a cluster of SNPs on chromosome 4 strongly associated with migratory orientation. Genes involved with the circadian clock, nervous system, and cell signaling were located here and included candidates implicated in smaller-scale studies of migration in different animal groups, supporting previous suggestions that there is a common gene package for migration [5]. Plumage color was more polygenic than migratory orientation but showed strong associations on the Z chromosome that included SNPs linked to TYRP1, a gene involved in the production of eumelanin. We integrated these results with genomic data from pure populations and found that regions associated with both phenotypes co-localized with regions of elevated relative differentiation between the groups. This finding relates to the literature on islands of differentiation [6-8] by implicating divergent selection in generating these peaks. Together, our results identify specific genomic regions involved in both the regulation of complex phenotypes across animal groups and speciation [9].
关于行为和数量性状的遗传学细节，目前仍仅限于少数生物。这类信息对于理解适应和物种形成至关重要，因为许多此类性状会减少分类群之间的基因流动[1 - 3]。杂交带为研究这一主题提供了理想的场所，因为它们由重组基因型组成，能够对区分自然种群的性状进行遗传定位[4]。我们在两组具有不同迁徙方向和羽毛颜色性状的斯温森氏画眉的杂交带中，研究了这两种可能导致物种形成的性状的遗传基础。我们在4号染色体上鉴定出一组与迁徙方向密切相关的单核苷酸多态性（SNP）。与生物钟、神经系统和细胞信号传导相关的基因位于此处，其中包括在不同动物群体的小规模迁徙研究中涉及的候选基因，这支持了先前关于存在一个共同的迁徙基因组合的观点[5]。羽毛颜色比迁徙方向具有更多的多基因特性，但在Z染色体上显示出强烈的关联，其中包括与TYRP1基因相关的SNP，TYRP1基因参与真黑素的产生。我们将这些结果与纯种群的基因组数据相结合，发现与这两种性状相关的区域与两组之间相对分化升高的区域共定位。这一发现通过暗示分歧选择在产生这些峰值中起作用，与关于分化岛的文献[6 - 8]相关。总之，我们的结果确定了参与跨动物群体复杂性状调控和物种形成的特定基因组区域[9]。
