Data from: Discordance between nuclear and mitochondrial genomes in sexual and asexual lineages of the freshwater snail Potamopyrgus antipodarum

The presence and extent of mitonuclear discordance in coexisting sexual and asexual lineages provides insight into 1) how and when asexual lineages emerged, and 2) the spatial and temporal scales at which the ecological and evolutionary processes influencing the evolution of sexual and asexual reproduction occur. Here, we used nuclear single-nucleotide polymorphism (SNP) markers and a mitochondrial gene to characterize phylogeographic structure and the extent of mitonuclear discordance in Potamopyrgus antipodarum. This New Zealand freshwater snail is often used to study the evolution and maintenance of sex because obligately sexual and obligately asexual individuals often coexist. While our data indicate that sexual and asexual P. antipodarum sampled from the same lake population are often genetically similar, suggesting recent origin of these asexuals from sympatric sexual P. antipodarum, we also found significantly more population structure in sexuals vs. asexuals. This latter result suggests that some asexual lineages originated in other lakes and/or in the relatively distant past. When comparing mitochondrial and nuclear population genetic structure, we discovered that one mitochondrial haplotype (‘1A’) was rare in sexuals, but common and widespread in asexuals. Haplotype 1A frequency and nuclear genetic diversity were not associated, suggesting that the commonness of this haplotype cannot be attributed entirely to genetic drift and pointing instead to a role for selection.

共存的有性与无性谱系中线粒体-核基因组不协调（mitonuclear discordance）的存在与程度，可为两项研究提供认知视角：其一，无性谱系的起源方式与时间；其二，调控有性与无性生殖演化的生态及进化过程所作用的时空尺度。本研究利用核基因组单核苷酸多态性（single-nucleotide polymorphism, SNP）标记与线粒体基因，对新西兰拟沼螺（Potamopyrgus antipodarum）的系统地理结构及线粒体-核基因组不协调程度进行了表征。该新西兰淡水螺常被用于探究有性生殖的演化与维持机制，因其种群中常共存专性有性个体与专性无性个体。尽管本研究数据显示，从同一湖泊种群中采集的有性与无性P. antipodarum个体通常遗传相似，表明这些无性类群是近期由同域分布的有性P. antipodarum起源而来，但我们同时发现，有性种群的种群结构显著多于无性种群。这一结果提示，部分无性谱系起源于其他湖泊，或起源于相对久远的过去。在对比线粒体与核基因组的种群遗传结构时，我们发现一种线粒体单倍型（‘1A’）在有性个体中极为罕见，但在无性个体中却十分常见且分布广泛。单倍型1A的频率与核遗传多样性并无关联，这表明该单倍型的高频率不能完全归因于遗传漂变，反而暗示了选择作用的参与。