Data from: Genetic relationships between Atlantic and Pacific populations of the notothenioid fish Eleginops maclovinus: the footprints of Quaternary glaciations in Patagonia

The genetic relationships between the Pacific and the Atlantic populations of marine costal biota in Southern South America have been analyzed in few studies, most of them relying on a single mitochondrial locus. We analyzed ten polymorphic microsatellite loci, isolated from a dinucleotide-enriched E. maclovinus genomic library, in a total of 240 individuals (48 from each of five sampled sites: two Atlantic, two Pacific and one in Beagle Channel). The results were contrasted against a previous work on the same species with mtDNA. Observed heterozygosity within localities ranged from 0.85 to 0.88 and the highest overall number of alleles was observed at the northernmost locality on the Pacific side (Concepción) but no clear geographic pattern arose from the data. On the other hand, the number of private alleles was negatively correlated with latitude (Spearman's rs test, p = 0.017). Among-population variance was low but significant (1.35 %; p < 0.0001, AMOVA) and low genetic differentiation between populations was observed (pairwise FST values ranged from 0 to 0.021). A Mantel test reveled a significant correlation between geographic distances and FST (r = 0.56, p = 0.047). This could be partially accounted for the Atlantic vs Pacific population differentiation detected in three different analyses (Structure, SAMOVA and a population phylogeny). The observed pattern is compatible with a history of separation into two glacial refugia, which was better captured by the multilocus microsatellite data than by the mtDNA analysis.

南美南部沿海海洋生物的太平洋种群与大西洋种群之间的遗传关系，目前仅在少量研究中得到探讨，其中绝大多数仅依托单个线粒体基因座（mitochondrial locus）展开分析。本研究对从二核苷酸富集的E. maclovinus基因组文库中筛选得到的10个多态性微卫星基因座（microsatellite loci）进行分析，共涉及240个个体——5个采样点各采集48个个体，其中2个位于大西洋海域、2个位于太平洋海域，剩余1个位于比格尔海峡（Beagle Channel）。本研究将所得结果与此前针对同一物种开展的线粒体DNA（mtDNA）相关研究进行对比。各采样点的观测杂合度介于0.85至0.88之间；太平洋海域最北端的采样点（康塞普西翁，Concepción）的总等位基因数最高，但数据未呈现明确的地理分布模式。另一方面，私有等位基因数量与纬度呈负相关关系（斯皮尔曼等级相关检验（Spearman's rs test），p=0.017）。种群间的遗传方差较低但具有统计学意义（1.35%；p<0.0001，分子方差分析（AMOVA））；种群间的遗传分化程度同样较低，两两群体间的FST值范围为0至0.021。曼特尔检验（Mantel test）结果显示，地理距离与FST值之间存在显著相关性（r=0.56，p=0.047）。这一结果可部分解释三种不同分析方法（Structure、SAMOVA以及种群系统发育分析）所检测到的大西洋与太平洋种群间的分化现象。本研究观测到的遗传模式与种群分化为两处冰期避难所的演化历史相符，且多基因座微卫星数据相较于线粒体DNA分析，更能准确捕捉这一演化信号。