Evolutionary History of Lake Tanganyika's Predatory Deepwater Cichlids.
Evolutionary History of Lake Tanganyika's Predatory Deepwater Cichlids.
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DOI：
10.1155/2012/716209
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Koblmüller S
中科院分区：
文献类型：
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作者：
Kirchberger PC;Sefc KM;Sturmbauer C;Koblmüller S
几项分子系统发育研究推测坦噶尼喀湖沿岸的慈鲷物种之间存在杂交。这一现象通常归因于湖泊水位引起的海岸线和栖息地的变化。这些允许异地分歧的地理分散的人口交替与当地限制的二次接触和不完全孤立的类群之间的基因渗入。相比之下，深水生境的特点是地理结构薄弱，基因流动的潜力很大，这可以解释深水的物种丰富度低于沿岸的谱系。出于同样的原因，不同的深水谱系在多样化的初期阶段就应该已经进化出强烈的内在生殖隔离，因此，既定谱系之间的杂交应该比沿岸的谱系更不频繁。我们测试这一假设在特有的坦噶尼喀湖深水慈鲷部落Bathybatini通过比较系统发育树的Hemibates和Bathybates种核多位点AFLP数据与基于线粒体序列的同源性。与我们的假设相一致，主要是全等树拓扑结构和负测试渗入提供了深水类群之间的渗入杂交没有证据。总之，核和线粒体数据建立了一个很好的支持，并建议物种形成过程中的生态隔离。
Hybridization among littoral cichlid species in Lake Tanganyika was inferred in several molecular phylogenetic studies. The phenomenon is generally attributed to the lake level-induced shoreline and habitat changes. These allow for allopatric divergence of geographically fragmented populations alternating with locally restricted secondary contact and introgression between incompletely isolated taxa. In contrast, the deepwater habitat is characterized by weak geographic structure and a high potential for gene flow, which may explain the lower species richness of deepwater than littoral lineages. For the same reason, divergent deepwater lineages should have evolved strong intrinsic reproductive isolation already in the incipient stages of diversification, and, consequently, hybridization among established lineages should have been less frequent than in littoral lineages. We test this hypothesis in the endemic Lake Tanganyika deepwater cichlid tribe Bathybatini by comparing phylogenetic trees of Hemibates and Bathybates species obtained with nuclear multilocus AFLP data with a phylogeny based on mitochondrial sequences. Consistent with our hypothesis, largely congruent tree topologies and negative tests for introgression provided no evidence for introgressive hybridization between the deepwater taxa. Together, the nuclear and mitochondrial data established a well-supported phylogeny and suggested ecological segregation during speciation.