Department of Ecology and Genetics, Animal Ecology, Uppsala University, Uppsala, Sweden.
Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, USA.
Nat Commun. 2024 Nov 29;15(1):10398. doi: 10.1038/s41467-024-54719-8.
Hybridization and introgression are widespread in nature, with important implications for adaptation and speciation. Since heterogametic hybrids often have lower fitness than homogametic individuals, a phenomenon known as Haldane's rule, loci inherited strictly through the heterogametic sex rarely introgress. We focus on the Y-chromosomal history of guenons, African primates that hybridized extensively in the past. Although our inferences suggest that Haldane's rule generally applies, we uncover a Y chromosome introgression event between two species ca. six million years after their initial divergence. Using simulations, we show that selection likely drove the introgressing Y chromosome to fixation from a low initial frequency. We identify non-synonymous substitutions on the novel Y chromosome as candidate targets of selection, and explore meiotic drive as an alternative mechanism. Our results provide a rare example of Y chromosome introgression, showing that the ability to produce fertile heterogametic hybrids likely persisted for six million years in guenons.
杂交和基因渗入在自然界中广泛存在，对适应和物种形成有重要意义。由于异配子杂种的适合度通常低于同配子个体，这一现象被称为霍尔丹法则，因此很少有严格通过异配子性别遗传的基因发生渗入。我们关注的是过去广泛杂交的非洲灵长类动物长尾猴的 Y 染色体历史。尽管我们的推断表明霍尔丹法则通常适用，但我们发现了一个大约在它们最初分化后 600 万年前发生在两个物种之间的 Y 染色体基因渗入事件。通过模拟，我们表明选择可能将渗入的 Y 染色体从低初始频率固定下来。我们确定了新的 Y 染色体上的非同义替换作为选择的候选靶标，并探索了减数分裂驱动作为一种替代机制。我们的研究结果提供了 Y 染色体基因渗入的罕见实例，表明在长尾猴中，产生可育异配子杂种的能力可能持续了六百万年。
