Population structure and gene flow reversals in Atlantic salmon (Salmo salar) over contemporary and long‐term temporal scales: effects of population size and life history
Population structure and gene flow reversals in Atlantic salmon (Salmo salar) over contemporary and long‐term temporal scales: effects of population size and life history
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DOI：
10.1111/j.1365-294x.2007.03541.x
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发表时间：
2007-11
影响因子：
4.9
通讯作者：
F. Palstra;M. O’Connell;D. Ruzzante
中科院分区：
文献类型：
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作者：
F. Palstra;M. O’Connell;D. Ruzzante
集合种群动态越来越多地被用于濒危物种的管理和保护。在这种情况下，不对称的基因流动模式可能是密度依赖性的，主要是从较大的种群迁移到较小的种群，这可能取决于它们的持久性。使用遗传标记，这种模式最近被记录在包括鲑鱼在内的各种生物中，这表明这可能是一种更普遍的模式。然而，集合种群理论并没有将基因流的不对称性限制在“源-库”结构上，也不需要这些模式在更长的进化时间尺度上保持不变。在溯河产卵的鲑科鱼类，基因流可以预期的形状由各种选择压力的基础归巢和分散（“流浪”）的行为。这些选择性力量的相对重要性在空间上和对于不同人口普查规模的人口来说是不同的。此外，种群间生活史变异对扩散和基因流动的影响仍然很难量化。我们研究人口结构和连接在大西洋鲑鱼（萨尔莫salar L.）来自纽芬兰和拉布拉多，这是一个该物种种群相对原始的地区。使用遗传变异的13个微卫星位点的样本（N = 1346），收集了20条河流，我们研究连接在几个区域和时间尺度和测试的假设，基因流的主要方向是从大到小的人口。我们拒绝这一假设，并发现迁移的方向性是受时间尺度的基因流进行评估。虽然大种群往往在当代时间尺度上充当扩散的来源，但这种模式往往会在进化的，合并衍生的时间尺度上发生变化，甚至逆转。此外，这些人口结构模式在不同地区之间存在差异，并与人口统计学和生活史属性相一致。我们没有发现性别偏见的分散基础基因流不对称的证据。我们的研究结果警告对概括大西洋鲑鱼基因流的方向性，并强调需要详细的区域研究，如果这些信息是有意义的应用在鲑鱼的保护和管理。
Metapopulation dynamics are increasingly invoked in management and conservation of endangered species. In this context, asymmetrical gene flow patterns can be density dependent, with migration occurring mainly from larger into smaller populations, which may depend on it for their persistence. Using genetic markers, such patterns have recently been documented for various organisms including salmonids, suggesting this may be a more general pattern. However, metapopulation theory does not restrict gene flow asymmetry to ‘source‐sink’ structures, nor need these patterns be constant over longer evolutionary timescales. In anadromous salmonids, gene flow can be expected to be shaped by various selective pressures underlying homing and dispersal (‘straying’) behaviours. The relative importance of these selective forces will vary spatially and for populations of different census size. Furthermore, the consequences of life‐history variation among populations for dispersal and hence gene flow remain poorly quantified. We examine population structure and connectivity in Atlantic salmon (Salmo salar L.) from Newfoundland and Labrador, a region where populations of this species are relatively pristine. Using genetic variation at 13 microsatellite loci from samples (N = 1346) collected from a total of 20 rivers, we examine connectivity at several regional and temporal scales and test the hypothesis that the predominant direction of gene flow is from large into small populations. We reject this hypothesis and find that the directionality of migration is affected by the temporal scale over which gene flow is assessed. Whereas large populations tend to function as sources of dispersal over contemporary timescales, such patterns are often changed and even reversed over evolutionary, coalescent‐derived timescales. These patterns of population structure furthermore vary between different regions and are compatible with demographic and life‐history attributes. We find no evidence for sex‐biased dispersal underlying gene flow asymmetry. Our findings caution against generalizations concerning the directionality of gene flow in Atlantic salmon and emphasize the need for detailed regional study, if such information is to be meaningfully applied in conservation and management of salmonids.