Isolation by distance and sharp discontinuities in gene frequencies:: implications for the phylogeography of an alpine insect species, Carabus solieri
Isolation by distance and sharp discontinuities in gene frequencies:: implications for the phylogeography of an alpine insect species, Carabus solieri
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DOI：
10.1111/j.1365-294x.2004.02212.x
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发表时间：
2004-07-01
影响因子：
4.9
通讯作者：
Rasplus, JY
中科院分区：
文献类型：
--
作者：
Garnier, S;Alibert, P;Rasplus, JY
遗传隔离距离（IBD）的分析是负责空间种群遗传结构的过程的研究，因此经常用于案例研究的首要重要性。然而，一个显着的IBD模式的识别并不一定意味着在基因频率的尖锐不连续的情况下。因此，识别分化实体之间的基因流动和/或次级接触的障碍仍然是群体生物学中的主要挑战。利用10个微卫星位点对高山昆虫红肩甲41个群体（1080个个体）的地理遗传结构进行了研究。所有人群显着分化和空间结构根据IBD在整个范围内。然而，聚类分析清楚地确定了与地理实体相对应的三个主要群体。虽然IBD也发生在每个集群内，但根据所考虑的人群组，人群结构不同。最南端的集群对应于该范围的最分散的部分。因此，它的特点是相对较高的分化水平与低的遗传多样性，和对地理距离的遗传分化的回归斜率是其他两个集群的三倍。集群内和集群间IBD模式的比较揭示了基因流动的障碍。这两种方法，IBD和聚类分析的比较，为我们提供了有价值的信息来推断物种的地理分布，特别是提出冰后期殖民路线位于意大利和法国东南部的两个潜在的避难所。我们的研究强调了IBD模式中基因流动障碍的可能混淆贡献，并强调了基于模型的聚类分析来识别这些障碍的实用性。
Analysis of genetic isolation by distance (IBD) is of prime importance for the study of processes responsible for spatial population genetic structure and is thus frequently used in case studies. However, the identification of a significant IBD pattern does not necessarily imply the absence of sharp discontinuities in gene frequencies. Therefore, identifying barriers to gene flow and/or secondary contact between differentiated entities remains a major challenge in population biology. Geographical genetic structure of 41 populations (1080 individuals) of an alpine insect species, Carabus solieri, was studied using 10 microsatellite loci. All populations were significantly differentiated and spatially structured according to IBD over the entire range. However, clustering analyses clearly identified three main clusters of populations, which correspond to geographical entities. Whereas IBD also occurs within each cluster, population structure was different according to which group of populations was considered. The southernmost cluster corresponds to the most fragmented part of the range. Consistently, it was characterized by relatively high levels of differentiation associated with low genetic diversity, and the slope of the regression of genetic differentiation against geographical distances was threefold those of the two other clusters. Comparisons of within-cluster and between-cluster IBD patterns revealed barriers to gene flow. A comparison of the two approaches, IBD and clustering analyses, provided us with valuable information with which to infer the phylogeography of the species, and in particular to propose postglacial colonization routes from two potential refugia located in Italy and in southeastern France. Our study highlights strongly the possible confounding contribution of barriers to gene flow to IBD pattern and emphasizes the utility of the model-based clustering analysis to identify such barriers.