Rapid polygenic response to secondary contact in a hybrid species

Secondary contact between closely related species can have genetic consequences. Competition for essential resources may lead to divergence in heritable traits that reduces interspecific competition, thus leading to increased genetic divergence. Conversely, hybridization and backcrossing can lead to genetic convergence. Here we study a population of a hybrid species, the Italian sparrow (Passer italiae), before and after it came into secondary contact with one of its parent species, the Spanish sparrow (P. hispaniolensis), in 2013. We demonstrate clear consequences of interspecific competition: Italian sparrows became outcompeted from a popular feeding site by its parent species, resulting in poorer body condition and a significant drop in population size. Although no significant morphological change could be detected, after only 3 years of sympatry the Italian sparrows had diverged significantly from the Spanish sparrows across a set of 81 protein coding genes. These temporal genetic c...

近缘物种间的次生接触（secondary contact）可引发遗传学后果。对生存必需资源的竞争可促使可遗传性状发生分化，进而降低种间竞争，最终加剧遗传分化。反之，杂交与回交过程则可引发遗传趋同。本研究以杂交物种意大利麻雀（Passer italiae）的种群为研究对象，追踪其在2013年与亲本之一的西班牙麻雀（P. hispaniolensis）发生次生接触前后的变化。本研究证实了种间竞争的显著效应：意大利麻雀被其亲本物种从热门觅食区域排挤，导致个体身体状况恶化，种群规模显著下降。尽管未检测到显著的形态学变化，但仅经过3年的同域共存（sympatry），意大利麻雀与西班牙麻雀在81个蛋白质编码基因（protein coding genes）的序列上已出现显著分化。这些随时间变化的遗传...