Hybridization could be a common phenomenon within the highly diverse lizard genus Liolaemus

Hybridization is likely to occur more often between closely related taxa that have had insufficient time to diverge to the point of reproductive incompatibility; hybridization between deeply divergent lineages is rare. In squamate reptiles, hybridization has been proposed as a possible explanation for the extensive paraphyly observed in mitochondrial gene trees in several species complexes of the South American lizard genus Liolaemus. One of the best-documented cases is within the L. boulengeri and L. rothi complexes, which diverged ~5.5 million years ago. Here we describe a comprehensive study for approaching the hybridization hypothesis between these lizard species complexes. We explored the level of gene tree discordance using the novel “extra lineage contribution” statistics (XLC, presented in this study), that quantifies the level of gene tree discordance contribution per individual within a species. We included molecular data (12 nuclear and 2 mitochondrial genes) from 127 indivi...

生殖隔离尚未形成的近缘类群之间更易发生杂交；而分化程度较深的支系间杂交则较为罕见。在有鳞目爬行动物中，里奥拉马蜥属（Liolaemus）的多个南美蜥蜴物种复合体的线粒体基因树呈现出广泛的并系现象，此前学界曾提出杂交可能是该现象的成因之一。其中证据最为充分的案例之一，便来自分化时长约550万年的L. boulengeri复合体与L. rothi复合体。本研究针对这两类蜥蜴物种复合体间的杂交假说开展了系统性探究：我们采用本研究提出的新型"支系额外贡献"（extra lineage contribution, XLC）统计量来评估基因树冲突程度，该统计量可量化物种内每个个体对基因树冲突的贡献水平。本研究纳入了来自127个个体的分子数据，包含12个核基因与2个线粒体基因……