Gene flow and genetic diversity in naturally fragmented metapopulations of deep-sea hydrothermal vent animals.
Gene flow and genetic diversity in naturally fragmented metapopulations of deep-sea hydrothermal vent animals.
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DOI：
10.1093/oxfordjournals.jhered.a023106
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发表时间：
1997-07
期刊：
影响因子：
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通讯作者：
R. Vrijenhoek
中科院分区：
文献类型：
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作者：
R. Vrijenhoek
深海热液喷口的短暂性预计将有利于具有良好定殖能力、高扩散率和快速个体生长率的物种。对喷口特有物种基因流的研究提供了对扩散模式和模式的一瞥。对于某些物种，基因流动的发生没有地理偏见（即，岛屿模式）;它们的扩散能力可能超出了抽样地理范围。对其他物种而言，遗传分化随着地理距离的增加而增加（距离隔离模式），并表明在邻近喷口之间的传播是一种踏脚石模式。第三组物种的遗传细分与脊轴相邻部分之间的地理偏移有关。这些物种都具有一个自由生活的幼虫阶段和基因流（Nm）的平均速率超过一个临界值。与此相反，一个端足类，育雏其年轻的显示隔离的证据，由距离沿着脊轴和不同的脊轴之间几乎完全隔离。早期演替物种（即，那些在新生喷口迅速建立种群的物种）也具有很高的遗传变异性，这可能是全球种群规模较大造成的。双壳类物种，这是有限的几个已知的喷口网站，出现在较晚的演替阶段，并具有较低水平的变化。一个物种的相对演替位置（早期与晚期）和总体丰度可能在决定居住在这些短暂环境中的种群的遗传多样性保留方面发挥重要作用。
The ephemeral nature of deep-sea hydrothermal vents is expected to favor species with good colonization abilities, high dispersal rates, and rapid individual growth rates. Studies of gene flow in vent-endemic species provide glimpses into modes and patterns of dispersal. For some species, gene flow occurs without geographical bias (i.e., island model); their dispersal capabilities probably exceed the sampled geographical range. For other species, genetic differentiation increases with geographical distance (isolation-by-distance model) and suggests a stepping-stone mode of dispersal between neighboring vents. Genetic subdivision in a third group of species is associated with geographical offsets between contiguous segments of a ridge axis. These species all possess a free-living larval stage and average rates of gene flow (Nm) exceeding the critical value of one. In contrast, an amphipod that broods its young shows evidence for isolation-by-distance along a ridge axis and nearly complete isolation between distinct ridge axes. Early successional species (i.e., those that rapidly establish populations at nascent vents) also have high levels of genetic variability that probably results from a larger global population size. Bivalve species, which are restricted to a few of the known vent sites, appear at a later successional stage and have lower levels of variability. The relative successional position (early versus late) and overall abundance of a species may play significant roles in determining the retention of genetic diversity in populations inhabiting these ephemeral environments.