Genomic Adaptations and Evolutionary History of the Extinct Scimitar-Toothed Cat, Homotherium latidens

作者：Ross Barnett, Michael V. Westbury, Marcela Sandoval‐Velasco, Filipe Garrett Vieira, Sungwon Jeon, Grant D. Zazula, Michael D. Martin, Simon Y. W. Ho, Niklas Mather, Shyam Gopalakrishnan, Jazmín Ramos‐Madrigal, Marc de Manuel, Marie Lisandra Zepeda Mendoza, Agostinho Antunes, Aldo Carmona Baez, Binia De Cahsan, Greger Larson, Stephen J. O’Brien, Eduardo Eizirik, Warren E. Johnson, Klaus‐Peter Koepfli, Andreas Wilting, Jörns Fickel, Love Dalén, Eline D. Lorenzen, Tomàs Marquès‐Bonet, Anders J. Hansen, Guojie Zhang, Jong Bhak, Nobuyuki Yamaguchi, M. Thomas P. Gilbert · 发表于：Current Biology · 年份：2020 · DOI：10.1016/j.cub.2020.09.051 · 被引用次数：56 · 研究领域：Genetic Mapping and Diversity in Plants and Animals、Genetic diversity and population structure、Chromosomal and Genetic Variations

Homotherium was a genus of large-bodied scimitar-toothed cats, morphologically distinct from any extant felid species, that went extinct at the end of the Pleistocene [1-4]. They possessed large, saber-form serrated canine teeth, powerful forelimbs, a sloping back, and an enlarged optic bulb, all of which were key characteristics for predation on Pleistocene megafauna [5]. Previous mitochondrial DNA phylogenies suggested that it was a highly divergent sister lineage to all extant cat species [6-8]. However, mitochondrial phylogenies can be misled by hybridization [9], incomplete lineage sorting (ILS), or sex-biased dispersal patterns [10], which might be especially relevant for Homotherium since widespread mito-nuclear discrepancies have been uncovered in modern cats [10]. To examine the evolutionary history of Homotherium, we generated a ∼7x nuclear genome and a ∼38x exome from H. latidens using shotgun and target-capture sequencing approaches. Phylogenetic analyses reveal Homotherium as highly divergent (∼22.5 Ma) from living cat species, with no detectable signs of gene flow. Comparative genomic analyses found signatures of positive selection in several genes, including those involved in vision, cognitive function, and energy consumption, putatively consistent with diurnal activity, well-developed social behavior, and cursorial hunting [5]. Finally, we uncover relatively high levels of genetic diversity, suggesting that Homotherium may have been more abundant than the limi...