Instituto de Biologia, Universidade Federal da Bahia, Salvador, Brazil.
Department of Biology, Lund University, Lund, SE-223 62, Sweden.
Heredity (Edinb). 2019 Nov;123(5):675-693. doi: 10.1038/s41437-019-0234-y. Epub 2019 May 23.
Combining phylogeographic approaches and hybrid zone inference in a single framework is a robust way to depict respectively the biogeographic history of lineages and the evolutionary processes responsible for speciation. Here, we studied the spatiotemporal patterns of diversification and characterize the hybrid zone between two Atlantic Forest spinetails (Synallaxis ruficapilla and Synallaxis cinerea) using mitochondrial DNA and nuclear (autosomal and Z-linked) genes. We consistently recovered divergence between and within the two species during the late Pliocene and Pleistocene using an isolation with migration model. Also, our results indicate distinct levels of introgression among lineages. Ecological niche models and demographic inferences, used to infer range distributions throughout the late Quaternary, were not consistent with the hypothesis of a large river as a primary barrier responsible for the divergence of the two species. Instead, a scenario of isolation and divergence followed by geographic expansion and admixture as a consequence of Quaternary climatic oscillations was supported. Paleomodels also were not consistent with the idea that the hybrid zone originated in primary differentiation and favor a secondary contact scenario. Model fitting indicated that clines of different loci spanning the hybrid zone are coincident and concordant. The narrow cline for one Z-linked locus could be indicative of some form of post-zygotic selection hindering genetic homogenization between the two species.
将系统发生地理学方法和杂种区推断结合在一个单一的框架中是描述谱系生物地理学历史和导致物种形成的进化过程的一种稳健方法。在这里，我们使用线粒体 DNA 和核（常染色体和 Z 连锁）基因研究了两个大西洋森林长尾鹦鹉（Synallaxis ruficapilla 和 Synallaxis cinerea）的时空多样化模式，并描绘了它们之间的杂种区。我们使用隔离与迁移模型一致地恢复了晚上新世和更新世期间两个物种之间和内部的分歧。此外，我们的结果表明，不同谱系之间存在不同程度的基因渗透。生态位模型和种群推断用于推断整个第四纪的范围分布，这与大河作为导致两个物种分歧的主要屏障的假设不一致。相反，支持了第四纪气候波动导致隔离和分歧、随后地理扩张和混合的情景。古模型也与杂种区起源于原始分化的观点不一致，而是支持二次接触情景。模型拟合表明，跨越杂种区的不同基因座的渐变线是一致和协调的。一个 Z 连锁基因座的狭窄渐变线可能表明某种形式的合子后选择阻碍了两个物种之间的遗传同质化。
