Pannell John R, Charlesworth Brian
Institute for Cell, Animal and Population Biology, University of Edinburgh, Edinburgh, EH9 3JT, United Kingdom.
Evolution. 1999 Jun;53(3):664-676. doi: 10.1111/j.1558-5646.1999.tb05362.x.
Many species exist as metapopulations in balance between local population extinction and recolonization, processes that may strongly affect the distribution of neutral genetic diversity within demes and in the metapopulation as a whole. In this paper we use both the infinite-alleles and the infinite-sites models to reframe Slatkin's propagulepool and migrant-pool models in terms of mean within-deme and among-deme genetic diversity; the infinite-sites model is particularly relevant to DNA sequence data. Population turnover causes a major reduction in neutral genetic diversity within demes, π , and in the metapopulation as a whole, π . This effect is particularly strong for propagulepool colonization, in which colonists are drawn from a single extant deme. Because metapopulation dynamics affect both within-deme and total metapopulation diversity similarly, comparisons between species with different ecologies on the basis of ratios such as F are difficult to interpret and absolute measures of divergence between populations should be used as well. Although the value of F in a metapopulation with local extinction depends strongly on the mode of colonization, this has almost no effect on the numerator of the F ratio, π - π , so that F is influenced mainly by the effect of the colonization mode on the denominator (π ). Our results also indicate that it is inappropriate to use measures of average within-deme diversity in species with population turnover to estimate the scaled mutation rate, θ, because extinction can greatly reduce π . Finally, we discuss the effect of population turnover on the effective size of a metapopulation.
许多物种以集合种群的形式存在，处于局部种群灭绝和重新定殖之间的平衡状态，这些过程可能会强烈影响中性遗传多样性在deme内以及整个集合种群中的分布。在本文中，我们使用无限等位基因模型和无限位点模型，根据deme内和deme间的平均遗传多样性，重新构建了斯莱特金的繁殖体库和迁移体库模型；无限位点模型与DNA序列数据特别相关。种群更替导致deme内的中性遗传多样性π以及整个集合种群的中性遗传多样性π大幅降低。这种影响对于繁殖体库定殖尤为强烈，在这种情况下，殖民者来自单个现存的deme。由于集合种群动态对deme内和集合种群总多样性的影响类似，因此基于F等比率对具有不同生态的物种进行比较很难解释，还应使用种群间分化的绝对度量。尽管在存在局部灭绝的集合种群中，F的值强烈依赖于定殖模式，但这对F比率的分子π - π几乎没有影响，因此F主要受定殖模式对分母（π）的影响。我们的结果还表明，在存在种群更替的物种中，使用deme内平均多样性的度量来估计尺度化突变率θ是不合适的，因为灭绝会极大地降低π。最后，我们讨论了种群更替对集合种群有效大小的影响。
