Within-population structure highlighted by differential introgression across semipermeable barriers to gene flow in Anguilla marmorata

In the marine environment, differential gene exchange between partially reproductively isolated taxa can result in introgression that extends over long distances due to high larval dispersal potential. However, the degree to which this process contributes to inter-locus variance of genetic differentiation within introgressed populations remains unclear. Using a genome-scan approach in the Indo-Pacific eel Anguilla marmorata, we investigated the degree of interpopulation genetic differentiation, the rate of introgression, and within-population genetic patterns at 858 AFLP markers genotyped in 1117 individuals. Three divergent populations were identified based on clustering analysis. Genetic assignments of individuals revealed the existence of different types of hybrids that tended to co-occur with parental genotypes in three population contact zones. Highly variable levels of genetic differentiation were found between populations across the AFLP markers, and reduced rates of introgressio...

在海洋生态系统中，部分生殖隔离的类群之间发生的差异化基因交流，可凭借极强的幼体扩散能力，形成可远距离传播的基因渐渗（introgression）现象。然而，这一过程对基因渐渗种群内遗传分化的位点间方差的贡献程度仍不明确。本研究以印太海域的花鳗鲡（Anguilla marmorata）为研究材料，采用基因组扫描（genome-scan）方法，对1117个个体的858个扩增片段长度多态性（AFLP, Amplified Fragment Length Polymorphism）标记进行基因分型，以此探究种群间遗传分化程度、基因渐渗速率以及种群内部的遗传模式。基于聚类分析，本研究共鉴定出3个分化显著的种群；个体遗传归属分析结果显示，在3个种群接触带中存在多种杂交类型，且这类杂交个体往往与亲本基因型共存。在所有AFLP标记对应的种群间，研究发现遗传分化水平存在高度变异，且基因渐渗速率呈降低趋势……