Departamento de Ecología e Hidrología, Facultad de Biología, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain.
Mol Ecol. 2011 May;20(9):1964-75. doi: 10.1111/j.1365-294X.2011.05068.x. Epub 2011 Apr 4.
We assessed the genetic structure of populations of the widely distributed sea cucumber Holothuria (Holothuria) mammata Grube, 1840, and investigated the effects of marine barriers to gene flow and historical processes. Several potential genetic breaks were considered, which would separate the Atlantic and Mediterranean basins, the isolated Macaronesian Islands from the other locations analysed, and the Western Mediterranean and Aegean Sea (Eastern Mediterranean). We analysed mitochondrial 16S and COI gene sequences from 177 individuals from four Atlantic locations and four Mediterranean locations. Haplotype diversity was high (H=0.9307 for 16S and 0.9203 for COI), and the haplotypes were closely related (π=0.0058 for 16S and 0.0071 for COI). The lowest genetic diversities were found in the Aegean Sea population. Our results showed that the COI gene was more variable and more useful for the detection of population structure than the 16S gene. The distribution of mtDNA haplotypes, the pairwise F(ST) values and the results of exact tests and amova revealed: (i) a significant genetic break between the population in the Aegean Sea and those in the other locations, as supported by both mitochondrial genes, and (ii) weak differentiation of the Canary and Azores Islands from the other populations; however, the populations from the Macaronesian Islands, Algarve and West Mediterranean could be considered to be a panmictic metapopulation. Isolation by distance was not identified in H. (H.) mammata. Historical events behind the observed findings, together with the current oceanographic patterns, were proposed and discussed as the main factors that determine the population structure and genetic signature of H. (H.) mammata.
我们评估了广泛分布的海参 Holothuria (Holothuria) mammata Grube, 1840 的种群遗传结构，并研究了海洋屏障对基因流动和历史进程的影响。考虑了几个潜在的遗传断裂，这些断裂将大西洋和地中海盆地、与其他分析地点隔离的马卡龙群岛以及西地中海和爱琴海（东地中海）分开。我们分析了来自四个大西洋地点和四个地中海地点的 177 个个体的线粒体 16S 和 COI 基因序列。单倍型多样性很高（16S 的 H=0.9307，COI 的 H=0.9203），单倍型密切相关（16S 的π=0.0058，COI 的π=0.0071）。遗传多样性最低的是爱琴海种群。我们的结果表明，COI 基因比 16S 基因更具变异性，更有助于检测种群结构。mtDNA 单倍型的分布、成对的 F(ST) 值以及确切检验和 amova 的结果表明：（i）爱琴海种群与其他地点的种群之间存在显著的遗传断裂，这两个线粒体基因都支持这一结果；（ii）加那利群岛和亚速尔群岛与其他种群的分化较弱；然而，马卡龙群岛、阿尔加维和西地中海的种群可以被认为是一个混合的集合种群。在 H. (H.) mammata 中没有发现隔离距离。提出并讨论了观察到的发现背后的历史事件以及当前的海洋模式，作为决定 H. (H.) mammata 种群结构和遗传特征的主要因素。
