Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, 78457, Germany.
Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales (MNCN-CSIC), José Gutiérrez Abascal, 2, Madrid, 28006, Spain.
Nat Commun. 2018 Aug 8;9(1):3159. doi: 10.1038/s41467-018-05479-9.
Lake Tanganyika is the oldest and phenotypically most diverse of the three East African cichlid fish adaptive radiations. It is also the cradle for the younger parallel haplochromine cichlid radiations in Lakes Malawi and Victoria. Despite its evolutionary significance, the relationships among the main Lake Tanganyika lineages remained unresolved, as did the general timescale of cichlid evolution. Here, we disentangle the deep phylogenetic structure of the Lake Tanganyika radiation using anchored phylogenomics and uncover hybridization at its base, as well as early in the haplochromine radiation. This suggests that hybridization might have facilitated these speciation bursts. Time-calibrated trees support that the radiation of Tanganyika cichlids coincided with lake formation and that Gondwanan vicariance concurred with the earliest splits in the cichlid family tree. Genes linked to key innovations show signals of introgression or positive selection following colonization of lake habitats and species' dietary adaptations are revealed as major drivers of colour vision evolution. These findings shed light onto the processes shaping the evolution of adaptive radiations.
坦噶尼喀湖是东非三种慈鲷鱼类适应性辐射中最古老和表型最多样化的一种。它也是马拉维湖和维多利亚湖中年轻的平行哈氏慈鲷辐射的发源地。尽管坦噶尼喀湖具有重要的进化意义，但主要坦噶尼喀湖谱系之间的关系以及慈鲷进化的总体时间尺度仍未得到解决。在这里，我们使用锚定系统发生基因组学来解开坦噶尼喀湖辐射的深层系统发育结构，并揭示了其基部以及哈氏慈鲷辐射早期的杂交现象。这表明杂交可能促进了这些物种爆发。时间校准的树支持坦噶尼喀慈鲷的辐射与湖泊形成同时发生，冈瓦纳大陆的隔离与慈鲷科家谱中最早的分裂一致。与殖民湖生境和物种饮食适应相关的关键创新基因显示出基因渗入或正选择的信号，揭示了颜色视觉进化的主要驱动因素。这些发现为塑造适应性辐射进化的过程提供了线索。
