Contreras-Días Hermans G, Moya Oscar, Oromí Pedro, Juan Carlos
Department de Biologia, Universitat de les Illes Balears, Palma de Mallorca, Spain.
Mol Ecol. 2003 Aug;12(8):2131-43. doi: 10.1046/j.1365-294x.2003.01884.x.
Phylogenetic and geographical nested clade analysis (NCA) methods were applied to mitochondrial DNA sequences of Pimelia darkling beetles (Coleoptera, Tenebrionidae) endemic to Gran Canaria, an island in the Canary archipelago. The three species P. granulicollis, P. estevezi and P. sparsa occur on the island, the latter with three recognized subspecies. Another species, P. fernandezlopezi (endemic to the island of La Gomera) is a close relative of P. granulicollis based on partial Cytochrome Oxidase I mtDNA sequences obtained in a previous study. Some of these beetles are endangered, so phylogeographical structure within species and populations can help to define conservation priorities. A total of about 700 bp of Cytochrome Oxidase II were examined in 18 populations and up to 75 individuals excluding outgroups. Among them, 22 haplotypes were exclusive to P. granulicollis and P. estevezi and 31 were from P. sparsa. Phylogenetic analysis points to the paraphyly of Gran Canarian Pimelia, as the La Gomera P. fernandezlopezi haplotypes are included in them, and reciprocal monophyly of two species groups: one constituted by P. granulicollis, P. estevezi and P. fernandezlopezi (subgenus Aphanaspis), and the other by P. sparsa'sensu lato'. The two species groups show a remarkably high mtDNA divergence. Within P. sparsa, different analyses all reveal a common result, i.e. conflict between current subspecific taxonomic designations and evolutionary units, while P. estevezi and P. fernandezlopezi are very close to P. granulicollis measured at the mtDNA level. Geographical NCA identifies several cases of nonrandom associations between haplotypes and geography that may be caused by allopatric fragmentation of populations with some cases of restriction of gene flow or range expansion. Analyses of molecular variance and geographical NCA allow definition of evolutionary units for conservation purposes in both species-groups and suggest scenarios in which vicariance caused by geological history of the island may have shaped the pattern of the mitochondrial genetic diversity of these beetles.
系统发育和地理嵌套分支分析（NCA）方法被应用于大加那利岛（加那利群岛中的一个岛屿）特有的拟步甲科（鞘翅目）暗黑拟步甲属甲虫的线粒体DNA序列。岛上有粒颈暗黑拟步甲、埃氏暗黑拟步甲和稀疏暗黑拟步甲这三个物种，后者有三个公认的亚种。另一个物种，费氏暗黑拟步甲（戈梅拉岛特有），根据先前研究中获得的部分细胞色素氧化酶I线粒体DNA序列，是粒颈暗黑拟步甲的近亲。这些甲虫中的一些处于濒危状态，因此物种和种群内的系统地理学结构有助于确定保护重点。在18个种群中，共检测了约7×10²bp的细胞色素氧化酶II，排除外群后检测了多达75个个体。其中，22个单倍型是粒颈暗黑拟步甲和埃氏暗黑拟步甲所特有的，31个来自稀疏暗黑拟步甲。系统发育分析表明大加那利岛暗黑拟步甲属是并系的，因为戈梅拉岛费氏暗黑拟步甲的单倍型包含在其中，并且两个物种组是相互单系的：一个由粒颈暗黑拟步甲、埃氏暗黑拟步甲和费氏暗黑拟步甲（Aphanaspis亚属）组成，另一个由广义的稀疏暗黑拟步甲组成。这两个物种组显示出非常高的线粒体DNA差异。在稀疏暗黑拟步甲中，不同的分析都揭示了一个共同的结果，即当前的亚种分类命名与进化单元之间存在冲突，而在mtDNA水平上，埃氏暗黑拟步甲和费氏暗黑拟步甲与粒颈暗黑拟步甲非常接近。地理NCA识别出单倍型与地理之间的几个非随机关联案例，这些案例可能是由种群的异域性片段化以及一些基因流受限或范围扩张的情况引起的。分子方差分析和地理NCA允许为两个物种组的保护目的定义进化单元，并提出岛屿地质历史导致的隔离可能塑造了这些甲虫线粒体遗传多样性模式的情景。
