Quantifying gene flow from spatial genetic structure data in a metapopulation of Chamaecrista fasciculata (Leguminosae)
Quantifying gene flow from spatial genetic structure data in a metapopulation of Chamaecrista fasciculata (Leguminosae)
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DOI：
10.1111/j.0014-3820.2003.tb00311.x
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发表时间：
2003-05-01
期刊：
影响因子：
3.3
通讯作者：
Hardy, OJ
中科院分区：
文献类型：
--
作者：
Fenster, CB;Vekemans, X;Hardy, OJ
在北美本土一年生豆科植物 Chamaecrista fasciculata（Leguminosae）的自然“元”群体中进行了广泛的同种酶调查，以量化不同空间尺度的遗传结构。然后，通过最近开发的基于连续群体模型的间接方法，使用个体之间的成对亲属关系系数来估计基因流。基因流的间接估计以邻域大小量化，平均值约为 150 个个体，在不同空间尺度（亚种群、种群、集合种群）之间是一致的。该基因流值位于先前根据对相同集合种群的花粉和种子传播的观察记录的直接估计范围内。使用基因流的直接测量作为参数的蒙特卡罗模拟进一步证明观察到的等位酶变异的空间模式与距离隔离模型一致。将之前发表的花粉传播距离估计值与本研究中的亲缘系数相结合，我们量化了相对于单个亚种群或整个集合种群的双亲近交。在邻里水平上，几乎没有观察到双亲近交，并且大多数偏离哈迪-温伯格基因型比例的解释是自体受精，而自交和双亲近交都有助于在集合种群水平上的非随机交配。基因流也通过基于不连续群体结构模型的间接方法进行估计。我们讨论了关于斑块种群结构对基因流估计的影响的这些结果。
An extensive allozyme survey was conducted within a natural "meta" population of the native North American annual legume, Chamaecrista fasciculata (Leguminosae) to quantify genetic structure at different spatial scales. Gene flow was then estimated by a recently developed indirect method based on a continuous population model, using pairwise kinship coefficients between individuals. The indirect estimates of gene flow, quantified in terms of neighborhood size, with an average value on the order of 150 individuals, were concordant among different spatial scales (subpopulation, population, metapopulation). This gene-flow value lies within the range of direct estimates previously documented from observations of pollen and seed dispersal for the same metapopulation. Monte Carlo simulations using the direct measures of gene flow as parameters further demonstrated that the observed spatial pattern of allozyme variation was congruent with a model of isolation by distance. Combining previously published estimates of pollen dispersal distances with kinship coefficients from this study, we quantified biparental inbreeding relative to either a single subpopulation or the whole metapopulation. At the level of a neighborhood, little biparental inbreeding was observed and most departure from Hardy-Weinberg genotypic proportions was explained by self-fertilization, whereas both selfing and biparental inbreeding contributed to nonrandom mating at the metapopulation level. Gene flow was also estimated from indirect methods based on a discontinuous population structure model. We discuss these results with respect to the effect of a patchy population structure on estimation of gene flow.