Bertrand Joris A M, Borsa Philippe, Chen Wei-Jen
Institute of Oceanography, National Taiwan University, N°1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan.
Institut de recherche pour le développement, UMR 250 'Ecologie marine tropicale des océans Pacifique et Indien', 101 promenade Roger-Laroque Anse Vata, BP A5, 98848 Nouméa cedex, New Caledonia.
Mol Ecol. 2017 May;26(9):2527-2542. doi: 10.1111/mec.14044. Epub 2017 Mar 8.
On evolutionary timescales, sea level oscillations lead to recurrent spatio-temporal variation in species distribution and population connectivity. In this situation, applying classical concepts of biogeography is challenging yet necessary to understand the mechanisms underlying biodiversity in highly diverse marine ecosystems such as coral reefs. We aimed at studying the outcomes of such complex biogeographic dynamics on reproductive isolation by sampling populations across a wide spatial range of a species-rich fish genus: the sergeants (Pomacentridae: Abudefduf). We generated a mutlilocus data set that included ten morpho-species from 32 Indo-West Pacific localities. We observed a pattern of mito-nuclear discordance in two common and widely distributed species: Abudefduf sexfasciatus and Abudefduf vaigiensis. The results showed three regional sublineages (Indian Ocean, Coral Triangle region, western Pacific) in A. sexfasciatus (0.6-1.5% divergence at cytb). The other species, A. vaigiensis, is polyphyletic and consists of three distinct genetic lineages (A, B and C) (9% divergence at cytb) whose geographic ranges overlap. Although A. vaigiensis A and A. sexfasciatus were found to be distinct based on nuclear information, A. vaigiensis A was found to be nested within A. sexfasciatus in the mitochondrial gene tree. A. sexfasciatus from the Coral Triangle region and A. vaigiensis A were not differentiated from each other at the mitochondrial locus. We then used coalescent-based simulation to characterize a spatially widespread but weak gene flow between the two species. We showed that these fishes are good candidates to investigate the evolutionary complexity of the discrepancies between phenotypic and genetic similarity in closely related species.
在进化时间尺度上，海平面振荡导致物种分布和种群连通性出现反复的时空变化。在这种情况下，应用经典生物地理学概念具有挑战性，但对于理解珊瑚礁等高度多样化海洋生态系统中生物多样性的潜在机制而言是必要的。我们旨在通过对一个物种丰富的鱼类属——军士鱼属（雀鲷科：阿波鱼属）广泛空间范围内的种群进行采样，研究这种复杂生物地理动态对生殖隔离的影响。我们生成了一个多位点数据集，其中包括来自32个印度 - 西太平洋地区的10个形态物种。我们在两个常见且分布广泛的物种——六带阿波鱼（Abudefduf sexfasciatus）和瓦氏阿波鱼（Abudefduf vaigiensis）中观察到线粒体 - 核不一致的模式。结果显示，六带阿波鱼有三个区域亚谱系（印度洋、珊瑚三角区、西太平洋）（细胞色素b的差异为0.6 - 1.5%）。另一个物种瓦氏阿波鱼是多系的，由三个不同的遗传谱系（A、B和C）组成（细胞色素b的差异为9%），其地理范围相互重叠。尽管基于核信息发现瓦氏阿波鱼A与六带阿波鱼不同，但在线粒体基因树中发现瓦氏阿波鱼A嵌套在六带阿波鱼内。来自珊瑚三角区的六带阿波鱼和瓦氏阿波鱼A在线粒体位点上没有分化。然后，我们使用基于溯祖理论的模拟来描述这两个物种之间空间上广泛但微弱的基因流。我们表明，这些鱼类是研究近缘物种表型和遗传相似性差异的进化复杂性的良好候选对象。
