Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA.
Department of Biology, Skidmore College, Saratoga Springs, New York, USA.
Mol Ecol. 2024 Nov;33(21):e17525. doi: 10.1111/mec.17525. Epub 2024 Sep 13.
Large structural variants in the genome, such as inversions, may play an important role in producing population structure and local adaptation to the environment through suppression of recombination. However, relatively few studies have linked inversions to phenotypic traits that are sexually selected and may play a role in reproductive isolation. Here, we found that geographic differences in the sexually selected plumage of a warbler, the common yellowthroat (Geothlypis trichas), are largely due to differences in the Z (sex) chromosome (males are ZZ), which contains at least one putative inversion spanning 40% (31/77 Mb) of its length. The inversions on the Z chromosome vary dramatically east and west of the Appalachian Mountains, which provides evidence of cryptic population structure within the range of the most widespread eastern subspecies (G. t. trichas). In an eastern (New York) and western (Wisconsin) population of this subspecies, female prefer different male ornaments; larger black facial masks are preferred in Wisconsin and larger yellow breasts are preferred in New York. The putative inversion also contains genes related to vision, which could influence mating preferences. Thus, structural variants on the Z chromosome are associated with geographic differences in male ornaments and female choice, which may provide a mechanism for maintaining different patterns of sexual selection in spite of gene flow between populations of the same subspecies.
基因组中的大片段结构变异，如倒位，可能通过抑制重组在产生种群结构和对环境的局部适应方面发挥重要作用。然而，很少有研究将倒位与性选择的表型特征联系起来，而这些特征可能在生殖隔离中起作用。在这里，我们发现，莺科的一种黄喉莺（Geothlypis trichas）的性选择羽毛的地理差异主要是由于 Z（性）染色体（雄性为 ZZ）的差异所致，该染色体至少包含一个长达 40%（31/77 Mb）的假定倒位。Z 染色体上的倒位在阿巴拉契亚山脉的东西两侧差异巨大，这为最广泛分布的东部亚种（G. t. trichas）的范围内存在隐生种群结构提供了证据。在这个亚种的东部（纽约）和西部（威斯康星州）种群中，雌性对不同的雄性装饰物有偏好；威斯康星州更喜欢大的黑色面罩，而纽约更喜欢大的黄色胸部。假定的倒位还包含与视觉相关的基因，这些基因可能影响交配偏好。因此，Z 染色体上的结构变异与雄性装饰物和雌性选择的地理差异有关，这可能为即使在同一亚种的种群之间存在基因流动的情况下，维持不同的性选择模式提供了一种机制。
