Accelerated evolution of land snails Mandarina in the oceanic Bonin Islands: Evidence from mitochondrial DNA sequences
Accelerated evolution of land snails Mandarina in the oceanic Bonin Islands: Evidence from mitochondrial DNA sequences
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DOI：
10.1111/j.1558-5646.1999.tb03781.x
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发表时间：
1999-04-01
期刊：
影响因子：
3.3
通讯作者：
Chiba, S
中科院分区：
文献类型：
--
作者：
Chiba, S
海洋小笠原群岛特有的陆生蜗牛属 Mandarina 不仅在形态和生态特征上表现出异常快速的进化，而且在 DNA 序列上也表现出异常快速的进化。基于线粒体 DNA (mtDNA) 序列的系统发育关系表明，在更新世期间，柑橘及其祖先之间产生了相当于科之间差异的形态差异。推测的系统发育表明，具有相似形态和生活栖息地的物种在不同时期、不同谱系和岛屿上反复、独立地出现。小笠原群岛的不同岛屿发生了连续的适应性辐射，每个岛屿上独立出现了占据树栖、半树栖和陆地栖息地的物种。由于贝壳形态与生活栖息地的密切关系，不同岛屿上相同生活栖息地的独立演化，造就了不同岛屿和谱系中具有相同贝壳形态的物种。这种快速的进化在系统发育关系和物种分类学之间产生了一些不一致。柑橘属物种间线粒体 DNA 的序列差异程度极高。柑橘内16S和12S核糖体RNA序列的最大序列差异程度分别为18.7%和17.7%，这表明柑橘线粒体DNA的进化极其迅速，比其他动物的标准速度快20倍以上。目前的研究表明，在适应性辐射期间，形态和生态特征的进化以极高的速率发生，特别是在支离破碎的环境中。
An endemic land snail genus Mandarina of the oceanic Bonin (Ogasawara) Islands shows exceptionally rapid evolution not only of morphological and ecological traits,but of DNA sequence. A phylogenetic relationship based on mitochondrial DNA (mtDNA) sequences suggests that morphological differences equivalent to the differences between families were produced between Mandarina and its ancestor during the Pleistocene. The inferred phylogeny shows that species with similar morphologies and life habitats appeared repeatedly and independently in different lineages and islands at different times. Sequential adaptive radiations occurred in different islands of the Bonin Islands and species occupying arboreal, semiarboreal, and terrestrial habitat arose independently in each island. Because of a close relationship between shell morphology and life habitat, independent evolution of the same life habitat in different islands created species possesing the same shell morphology in different islands and Lineages. This rapid evolution produced some incongruences between phylogenetic relationship and species taxonomy. Levels of sequence divergence of mtDNA among the species of Mandarina is extremely high. The maximum level of sequence divergence at 16S and 12S ribosomal RNA sequence within Mandarina are 18.7% and 17.7%, respectively, and this suggests that evolution of mtDNA of Mandarina is extremely rapid, more than 20 times faster than the standard rate in other animals. The present examination reveals that evolution of morphological and ecological traits occurs at extremely high rates in the time of adaptive radiation, especially in fragmented environments.