Data from: Hybrid origin of Audubon's warbler

Several animal species have recently been shown to have hybrid origins, but no avian examples have been documented with molecular evidence. We investigate whether the Audubon's warbler, one of four visually distinct species in the yellow-rumped warbler (Dendroica coronata) complex, may have originated through hybridization between two other species in this group, the myrtle warbler and black-fronted warbler. Analysis of nuclear AFLP and sequence markers shows that Audubon's warblers are genetically intermediate, and carry a mixture of alleles otherwise found only in one or the other of their putative parental species. Audubon's warblers also carry two deeply divergent mitochondrial DNA lineages, each shared with only one putative parental form. Broad clines between Audubon's and black-fronted warblers in AFLP markers call into question the validity of these two forms as full species; nevertheless, our results suggest that the Audubon’s warbler likely originated through hybridization between two long-diverged species. It is likely that more cases of avian species of hybrid origin will be revealed by surveys of variation in nuclear DNA and other traits.近期多项研究已证实多种动物类群具有杂交起源，但目前尚无分子证据支撑的鸟类杂交起源案例被报道。本研究以黄腰林莺（*Dendroica coronata*）复合群中4个形态差异显著的物种之一——奥杜邦林莺（Audubon's warbler）为研究对象，探讨其是否由该复合群内另外两个类群：桃金娘林莺（myrtle warbler）与黑额林莺（black-fronted warbler）杂交演化而来。对核AFLP标记与序列标记的分析结果显示，奥杜邦林莺的遗传特征处于两个推定亲本物种之间，且携有仅分别存在于这两个亲本类群中的等位基因混合体。奥杜邦林莺同时拥有两个高度分化的线粒体DNA谱系，且每个谱系均仅与其中一个推定亲本类群共享。核AFLP标记所揭示的奥杜邦林莺与黑额林莺之间广泛的渐变群现象，对这两个类群作为独立物种的分类有效性提出了质疑；尽管如此，本研究结果仍表明，奥杜邦林莺大概率起源于两个分化已久的物种间的杂交事件。后续通过核DNA及其他性状的变异调查，或将揭示更多鸟类杂交起源物种的案例。