Introgression between Sphyrapicus nuchalis and S. varius sapsuckers in a hybrid zone in west-central Alberta

Studying species interactions at hybrid zones allows biologists to understand the forces that promote speciation. Hybridization among Sphyrapicus nuchalis, S. varius, and S. ruber has long been acknowledged, and hybrid zones between S. nuchalis/S. ruber and S. varius/S. ruber have been characterized with both genetic and genomic data. Using a combination of next-generation Restriction Site-Associated DNA sequencing (RAD-Seq) and traditional genetic methods, we examined patterns of introgression in the poorly characterized S. nuchalis/S. varius contact zone; the two most similar species in the complex, though they are not each other’s closest relatives. We found high introgression rates, with several early and many advanced generation hybrids along a 275 km stretch of Rocky Mountain foothill, pointing to a well-established hybrid zone with hybrid individuals backcrossing with individuals from the parental species and each other. Plumage colouration in the hybrid zone was a relatively poo...

在杂交带开展物种互作研究，可帮助生物学家解析推动物种形成的演化动力。黄腹吸汁啄木鸟（Sphyrapicus nuchalis）、红胸吸汁啄木鸟（S. varius）与红腹吸汁啄木鸟（S. ruber）之间的杂交现象早已得到学界认可，且S. nuchalis/S. ruber、S. varius/S. ruber之间的杂交带已通过遗传学与基因组学数据完成特征刻画。本研究结合下一代限制性位点关联DNA测序（Restriction Site-Associated DNA sequencing, RAD-Seq）与传统遗传学方法，对特征解析尚不充分的S. nuchalis与S. varius接触带的基因渐渗模式展开分析；二者是该类群中形态最为相似的两个物种，尽管它们并非彼此的近缘类群。研究发现该区域存在较高的基因渐渗速率：在落基山山麓275公里的样带范围内，存在多只早期世代杂合体与大量晚期世代杂合体，表明这是一个成熟稳定的杂交带，杂合个体可与亲本物种及其他杂合个体回交。该杂交带内的羽色特征解析相对较为...