Phylogeography, colonization and population history of the Midas cichlid species complex (Amphilophus spp.) in the Nicaraguan crater lakes
Phylogeography, colonization and population history of the Midas cichlid species complex (Amphilophus spp.) in the Nicaraguan crater lakes
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DOI：
10.1186/1471-2148-10-326
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发表时间：
2010-10-26
影响因子：
3.4
通讯作者：
Meyer, Axel
中科院分区：
文献类型：
--
作者：
Barluenga, Marta;Meyer, Axel
背景：阐明驱动物种形成的机制需要详细了解整个范围内早期物种的系统发育关系和系统发育地理学以及它们的殖民历史。迈达斯丽鱼科鱼种复杂 Amphilophus spp。已被证明是研究生态专业化、性选择和同域物种形成机制的强大模型系统。在这里，我们使用两种类型的分子标记（线粒体 DNA 控制区和 15 个微卫星）对尼加拉瓜完整的 Midas Cichlid 物种复合体（> 2000 个个体）进行了全面综合的系统发育地理学分析，涵盖整个分布范围。我们调查了该物种复合体的大多数已知湖泊种群，并重建了它们的殖民历史，以便区分不同的物种形成情景。结果：我们发现大型湖泊包含更古老且更加多样化的米达斯丽鱼种群，而所有火山口湖都拥有更年轻且遗传变异较小的物种组合。这些大型湖泊似乎反复充当所有火山口湖的源种群，我们的数据表明火山口湖之间的动物交换极不可能。尽管它们的起源最近（通常只有几千年）并且共同起源于尼加拉瓜的两个大湖，但所有火山口湖迈达斯慈鲷辐射都经历了独立但平行的进化，并包含不同的遗传单位。事实上，其中几个火山口湖含有多种遗传上不同的早期物种，这些物种很可能是通过同域物种形成而产生的。一些火山口湖辐射可以追溯到一个单一的祖先谱系，但有些似乎有多个创始谱系。每个火山口湖的殖民时间各不相同，尽管大多数发生的时间比 20,000 年前更晚（可能远得多）。结论：火山口湖种群的遗传分化与创始谱系的数量直接相关，但与殖民时间无关。有趣的是，表型分化水平和物种形成事件似乎与这两个因素无关。
Background: Elucidation of the mechanisms driving speciation requires detailed knowledge about the phylogenetic relationships and phylogeography of the incipient species within their entire ranges as well as their colonization history. The Midas cichlid species complex Amphilophus spp. has been proven to be a powerful model system for the study of ecological specialization, sexual selection and the mechanisms of sympatric speciation. Here we present a comprehensive and integrative phylogeographic analysis of the complete Midas Cichlid species complex in Nicaragua (> 2000 individuals) covering the entire distributional range, using two types of molecular markers (the mitochondrial DNA control region and 15 microsatellites). We investigated the majority of known lake populations of this species complex and reconstructed their colonization history in order to distinguish between alternative speciation scenarios.Results: We found that the large lakes contain older and more diverse Midas Cichlid populations, while all crater lakes hold younger and genetically less variable species assemblages. The large lakes appear to have repeatedly acted as source populations for all crater lakes, and our data indicate that faunal exchange among crater lakes is extremely unlikely. Despite their very recent (often only a few thousand years old) and common origin from the two large Nicaraguan lakes, all crater lake Midas Cichlid radiations underwent independent, but parallel, evolution, and comprise distinct genetic units. Indeed several of these crater lakes contain multiple genetically distinct incipient species that most likely arose through sympatric speciation. Several crater lake radiations can be traced back to a single ancestral line, but some appear to have more than one founding lineage. The timing of the colonization(s) of each crater lake differs, although most of them occurred more (probably much more) recently than 20,000 years ago.Conclusion: The genetic differentiation of the crater lake populations is directly related to the number of founding lineages, but independent of the timing of colonization. Interestingly, levels of phenotypic differentiation, and speciation events, appeared independent of both factors.