Catarino Diana, Knutsen Halvor, Veríssimo Ana, Olsen Esben Moland, Jorde Per Erik, Menezes Gui, Sannæs Hanne, Stanković David, Company Joan Baptista, Neat Francis, Danovaro Roberto, Dell'Anno Antonio, Rochowski Bastien, Stefanni Sergio
MARE-Marine and Environmental Sciences Centre, Department of Oceanography and Fisheries, University of the Azores, Rua Prof. Dr. Frederico Machado, Horta, Azores, Portugal.
IMAR-Institute of Marine Research, Department of Oceanography and Fisheries, University of the Azores, Rua Prof. Dr. Frederico Machado, Horta, Azores, Portugal.
Mol Ecol. 2015 Dec;24(24):6061-79. doi: 10.1111/mec.13453. Epub 2015 Dec 7.
Knowledge of the mechanisms limiting connectivity and gene flow in deep-sea ecosystems is scarce, especially for deep-sea sharks. The Portuguese dogfish (Centroscymnus coelolepis) is a globally distributed and near threatened deep-sea shark. C. coelolepis population structure was studied using 11 nuclear microsatellite markers and a 497-bp fragment from the mtDNA control region. High levels of genetic homogeneity across the Atlantic (Φ(ST) = -0.0091, F(ST) = 0.0024, P > 0.05) were found suggesting one large population unit at this basin. The low levels of genetic divergence between Atlantic and Australia (Φ(ST) = 0.0744, P < 0.01; F(ST) = 0.0015, P > 0.05) further suggested that this species may be able to maintain some degree of genetic connectivity even across ocean basins. In contrast, sharks from the Mediterranean Sea exhibited marked genetic differentiation from all other localities studied (Φ(ST) = 0.3808, F(ST) = 0.1149, P < 0.001). This finding suggests that the shallow depth of the Strait of Gibraltar acts as a barrier to dispersal and that isolation and genetic drift may have had an important role shaping the Mediterranean shark population over time. Analyses of life history traits allowed the direct comparison among regions providing a complete characterization of this shark's populations. Sharks from the Mediterranean had markedly smaller adult body size and size at maturity compared to Atlantic and Pacific individuals. Together, these results suggest the existence of an isolated and unique population of C. coelolepis inhabiting the Mediterranean that most likely became separated from the Atlantic in the late Pleistocene.
对于限制深海生态系统中连通性和基因流动的机制，我们知之甚少，尤其是对于深海鲨鱼。葡萄牙角鲨（Centroscymnus coelolepis）是一种分布于全球且接近濒危的深海鲨鱼。我们使用11个核微卫星标记和线粒体DNA控制区的一个497碱基对片段，对葡萄牙角鲨的种群结构进行了研究。研究发现，整个大西洋的遗传同质性水平很高（Φ(ST) = -0.0091，F(ST) = 0.0024，P > 0.05），这表明在这个海域存在一个大的种群单元。大西洋和澳大利亚之间的遗传分化水平较低（Φ(ST) = 0.0744，P < 0.01；F(ST) = 0.0015，P > 0.05），这进一步表明该物种甚至可能能够在不同大洋盆地之间维持一定程度的基因连通性。相比之下，来自地中海的鲨鱼与其他所有研究地点的鲨鱼表现出明显的遗传分化（Φ(ST) = 0.3808，F(ST) = 0.1149，P < 0.001）。这一发现表明，直布罗陀海峡的浅深度起到了扩散障碍的作用，随着时间的推移，隔离和遗传漂变可能在塑造地中海鲨鱼种群方面发挥了重要作用。对生活史特征的分析使得能够对不同区域进行直接比较，从而全面描述这种鲨鱼的种群特征。与大西洋和太平洋的个体相比，来自地中海的鲨鱼成年体型和成熟时的体型明显更小。综合这些结果表明，在地中海存在一个孤立且独特的葡萄牙角鲨种群，这个种群很可能在更新世晚期与大西洋种群分离。
