Zoologisches Forschungsmuseum Alexander Koenig, Adenauerallee 160, Bonn, Germany.
J Evol Biol. 2012 Jan;25(1):138-48. doi: 10.1111/j.1420-9101.2011.02409.x. Epub 2011 Nov 9.
Hybridization in animals is a much more common phenomenon as previously thought and may have profound implications for speciation research. The cichlid genus Steatocranus (Teleostei: Cichlidae), a close relative to members of the East African cichlid radiations, radiated under riverine conditions in the lower Congo rapids and produced a small species flock. Previous phylogenetic analyses suggested that hybridization occurred and contributed to speciation in this genus. A re-analysis of an already published 2000 loci-AFLP data set explicitly testing for patterns of ancient gene flow provided strong evidence for a highly reticulate phylogenetic history of the genus. We provide, to our knowledge, the first example of a complex reticulate network in vertebrates, including multiple closely related species connected through ancient as well as recent gene flow. In this context, the limited validity of strictly bifurcating tree hypotheses as a phylogenetic basis for hypothesis testing in evolutionary biology is discussed.
动物杂交比之前认为的更为普遍，这可能对物种形成研究具有深远的影响。慈鲷属 Steatocranus（硬骨鱼纲：慈鲷科）是东非慈鲷辐射的近亲，在刚果河急流的河流条件下辐射，并产生了一个小的物种群。先前的系统发育分析表明，杂交发生并促成了该属的物种形成。对已经发表的 2000 个位点 AFLP 数据集的重新分析，明确测试了古老基因流的模式，为该属高度网状的系统发育历史提供了强有力的证据。我们提供了，据我们所知，脊椎动物中第一个复杂的网状网络的例子，包括通过古老和近期基因流连接的多个密切相关的物种。在这种情况下，讨论了严格的二分树假设作为进化生物学中假设检验的系统发育基础的有限有效性。
