Data from: Phenotypic and genotypic variation across a stable white-eye (Zosterops sp.) hybrid zone in central South Africa

The interbreeding of two species after a period of separation (secondary contact) most often results in stable areas of hybridization or tension zones characterized by selection against hybrid individuals. Three plumage forms of Zosterops meet and interbreed in central South Africa. Here we examine how phenotypic measures (biometric and plumage) and genotypic markers (mitochondrial and nuclear DNA) change through a putative hybrid zone located in the area where the ranges of the Orange River white-eye Zosterops pallidus and a subspecies of the Cape white-eye Zosterops virens capensis meet. Four of the five sequenced loci (i.e. ATP6, MUSK, GADPH and TGF-β2) showed strong divergence and differentiation between allopatric parental populations, whereas the sex-linked CHD1Z locus exhibited high homogeneity. Microsatellite data also distinguished between pure Z. pallidus and Z. v. capensis populations. Together, the nuclear data (introns and microsatellites) identified at least 12 hybrid individuals as later generation hybrids (i.e. F2 or backcrosses), and no F1 hybrids were detected. As genetic incompatibility does not appear to play a role in restricting this stable hybrid zone, it is likely that environmental conditions including biome type and edge effect are constraining hybrid zone movement.两个物种在经历一段时期的生殖隔离后再度接触（即次生接触）时发生的杂交，通常会形成稳定的杂交区域或杂交张力区，这类区域的典型特征是对杂交个体存在选择淘汰作用。南非中部地区有三种羽色型的绣眼鸟属（Zosterops）鸟类在此相遇并发生杂交。本研究聚焦于奥兰治河绣眼（Zosterops pallidus）与开普绣眼开普亚种（Zosterops virens capensis）的分布区交汇地带的疑似杂交带，探讨表型指标（包括形态测量学与羽色特征）以及遗传标记（线粒体DNA与核DNA）在该杂交带内的变化规律。在测序获得的5个基因座中，有4个（即ATP6、MUSK、GADPH与TGF-β2）在异域亲本种群间表现出显著的遗传分化与序列差异，而伴性遗传的CHD1Z基因座则呈现高度的遗传均一性。微卫星标记数据同样可区分纯合的奥兰治河绣眼与开普绣眼开普亚种种群。综合核基因组数据（内含子与微卫星标记）的分析结果，研究共鉴定出至少12个后世代杂交个体（即F2代或回交个体），未检测到F1代杂交个体。鉴于遗传不相容性似乎并未对该稳定杂交带的维持起到限制作用，推测包括生物群系类型与边缘效应在内的环境条件，正在约束该杂交带的移动范围。