Data from: Phylogeographic analysis of Ligia oceanica (Crustacea: Isopoda) reveals two deep divergent mitochondrial lineages

Isopods of the species Ligia oceanica are typical inhabitants of the rocky intertidal of the northern European coastline. The aim of this study was to assess the genetic structure of this species using mitochondrial and nuclear sequence data. We analysed partial mitochondrial cytochrome c oxidase subunit I (CO1) and 16S rRNA gene sequence data of 161 specimens collected from ten sites ranging from Spain to Norway. For selected specimens, we also sequenced the hypervariable V7 expansion segment of the nuclear 18S rRNA gene as a supplementary marker. Furthermore, we studied the infection rate of all analysed specimens by the alphaproteobacterium Wolbachia. Our analyses revealed two deeply divergent mitochondrial lineages for Ligia oceanica that probably diverged in the late Pliocene to mid Pleistocene. One lineage comprised specimens from northern populations (‘lineage N’) and one primarily those from France and Spain (‘lineage S’). Distribution patterns of the haplotypes and the genetic distances between both lineages revealed two populations that diverged before the Last Glacial Maximum. Given that we found no homogenization of mitochondrial haplotypes, our present results also reject any influence of Wolbachia on the observed mtDNA variability

大洋海蟑螂（Ligia oceanica）属于等足目动物（Isopods），是北欧海岸岩相潮间带的典型栖息类群。本研究旨在利用线粒体与核基因序列数据，解析该物种的遗传结构。我们对采自西班牙至挪威10个采样点的161份标本的线粒体细胞色素c氧化酶亚基I（CO1）与16S核糖体RNA（16S rRNA）基因的部分序列进行了分析。针对部分选定标本，我们还对核基因18S核糖体RNA（18S rRNA）的高变V7扩张区进行了测序，作为补充分子标记。此外，我们还检测了所有分析标本感染α-变形菌门沃尔巴克氏体（Wolbachia）的比率。分析结果显示，大洋海蟑螂存在两个深度分化的线粒体谱系，其分化时间大概率处于上新世晚期至更新世中期。其中一支为北部种群标本（命名为'lineage N'），另一支则主要包含来自法国与西班牙的标本（命名为'lineage S'）。单倍型分布模式与两个谱系间的遗传距离均表明，这两个种群的分化发生在末次盛冰期之前。鉴于未检测到线粒体单倍型的同质化现象，本研究结果同时排除了沃尔巴克氏体对观测到的线粒体DNA（mtDNA）变异存在影响的可能性。