Rocha Joana L, Vaz Pinto Pedro, Siegismund Hans R, Meyer Matthias, Jansen van Vuuren Bettine, Veríssimo Luís, Ferrand Nuno, Godinho Raquel
CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, Vairão, Portugal.
Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal.
Mol Ecol. 2022 May;31(10):2968-2984. doi: 10.1111/mec.16427. Epub 2022 Mar 31.
The evolutionary history of African ungulates has been explained largely in the light of Pleistocene climatic oscillations and the way these influenced the distribution of vegetation types, leading to range expansions and/or isolation in refugia. In contrast, comparatively fewer studies have addressed the continent's environmental heterogeneity and the role played by its geomorphological barriers. In this study, we performed a range-wide analysis of complete mitogenomes of sable antelope (Hippotragus niger) to explore how these different factors may have contributed as drivers of evolution in southcentral Africa. Our results supported two sympatric and deeply divergent mitochondrial lineages in west Tanzanian sables, which can be explained as the result of introgressive hybridization of a mitochondrial ghost lineage from an archaic, as-yet-undefined, congener. Phylogeographical subdivisions into three main lineages suggest that sable diversification may not have been driven solely by climatic events affecting populations differently across a continental scale. Often in interplay with climate, geomorphological features have also clearly shaped the species' patterns of vicariance, where the East Africa Rift System and the Eastern Arc Mountains acted as geological barriers. Subsequent splits among southern populations may be linked to rearrangements in the Zambezi system, possibly framing the most recent time when the river attained its current drainage profile. This work underlines how the use of comprehensive mitogenomic data sets on a model species with a wide geographical distribution can contribute to a much-enhanced understanding of environmental, geomorphological and evolutionary patterns in Africa throughout the Quaternary.
非洲有蹄类动物的进化史在很大程度上是根据更新世气候振荡以及这些振荡对植被类型分布的影响来解释的，这些影响导致了动物种群在避难所中的范围扩张和/或隔离。相比之下，针对该大陆环境异质性及其地貌屏障所起作用的研究相对较少。在本研究中，我们对貂羚（Hippotragus niger）的完整线粒体基因组进行了全范围分析，以探究这些不同因素如何作为非洲中南部进化的驱动力发挥作用。我们的结果支持了坦桑尼亚西部貂羚存在两个同域且线粒体谱系差异很大的谱系，这可以解释为来自一个古老的、尚未明确的同属线粒体幽灵谱系的渐渗杂交结果。系统发育地理细分出三个主要谱系，这表明貂羚的多样化可能并非仅仅由影响整个大陆不同种群的气候事件驱动。地貌特征通常与气候相互作用，也明显塑造了该物种的地理隔离模式，其中东非大裂谷系统和东弧山脉起到了地质屏障的作用。南部种群随后的分裂可能与赞比西河水系的重新排列有关，这可能确定了该河流形成当前排水轮廓的最近时间。这项工作强调了对具有广泛地理分布的模式物种使用全面的线粒体基因组数据集，有助于大大增强对整个第四纪非洲环境、地貌和进化模式的理解。
