Phylogeny of a rapidly evolving clade: The cichlid fishes of Lake Malawi, East Africa
Phylogeny of a rapidly evolving clade: The cichlid fishes of Lake Malawi, East Africa
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DOI：
10.1073/pnas.96.9.5107
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发表时间：
1999-04-27
影响因子：
11.1
通讯作者：
Kocher, TD
中科院分区：
文献类型：
--
作者：
Albertson, RC;Markert, JA;Kocher, TD
马拉维湖中有超过 500 种慈鲷鱼群，它们是在过去百万年里从共同祖先进化而来的。该群体的快速多样化归因于形态适应和性选择，但这些机制的相对时间和重要性尚不清楚。该类群的系统发育将有助于确定每种机制在群体进化中所扮演的角色。之前使用分子方法重建这些类群之间关系的尝试因物种内祖先多态性的持续存在而受挫。在这里，我们描述了 DNA 指纹技术的结果，该技术通过检查分布在基因组中的数千个多态性来克服这个问题。由此产生的树状图平均了数千个基因的进化历史，并且应该准确地反映这些物种的进化历史。我们的树解决了密切相关的马拉维湖慈鲷之间的关系，并提供了对该群体物种形成模式的见解。我们证明营养形态的适应性分歧在湖泊的早期历史中发挥了重要作用。随后出现了物种多样性，营养形态几乎没有变化，这表明其他力量导致了这些鱼类的持续物种形成。
Lake Malawi contains a flock of >500 species of cichlid fish that have evolved from a common ancestor within the last million years. The rapid diversification of this group has been attributed to morphological adaptation and to sexual selection, but the relative timing and importance of these mechanisms is not known. A phylogeny of the group would help identify the role each mechanism has played in the evolution of the flock Previous attempts to reconstruct the relationships among these taxa using molecular methods have been frustrated by the persistence of ancestral polymorphisms within species. Here we describe results from a DNA fingerprinting technique that overcomes this problem by examining thousands of polymorphisms distributed across the genome. The resulting dendrogram averages the evolutionary history of thousands of genes and should accurately reflect the evolutionary history of these species. Our tree resolves relationships among closely related Lake Malawi cichlids and provides insights into the pattern of speciation in this group. We demonstrate that adaptive divergence in trophic morphology played an important role during the early history of the lake. Subsequent species diversity has arisen with little change in trophic morphology, which suggests that other forces are responsible for the continued speciation of these fishes.