Mitochondrial haplotypes and the New Zealand origin of clonal European Potamopyrgus, an invasive aquatic snail

The small aquatic snail Potamopyrgus antipodarum is an important invading species in Europe, Australia and North America. European populations are generally believed to derive from accidental introductions from New Zealand, probably dating back to the mid‐19th century. We have employed mitochondrial DNA sequences to test the proposed New Zealand origin of European Potamopyrgus, and to learn more about its genealogical history. Using a 481‐bp region of the 16S ribosomal RNA gene, we identified 17 distinct haplotypes among 65 snails from New Zealand. In marked contrast, only two haplotypes were found across all European samples, which cover a large geographical area. Importantly, these two haplotypes are shared with snails from the North Island of New Zealand. Due to sampling limitations we cannot rule out a South Island origin for one of the haplotypes, but our results clearly demonstrate the New Zealand origin of European populations. The marked divergence among the two European haplotypes implies the successful colonization by two distinct mitochondrial lineages, which is consistent with previous data based on nuclear markers.

小型水生螺类新西兰泥蜗（Potamopyrgus antipodarum）是欧洲、澳大利亚和北美洲的一种重要入侵物种。人们普遍认为欧洲的种群源自新西兰的意外引入，时间可能追溯到19世纪中叶。我们利用线粒体DNA序列来检验所提出的欧洲新西兰泥蜗源自新西兰的观点，并进一步了解其谱系历史。利用16S核糖体RNA基因的一个481碱基对区域，我们在来自新西兰的65只螺中鉴定出17种不同的单倍型。形成鲜明对比的是，在涵盖大片地理区域的所有欧洲样本中仅发现两种单倍型。重要的是，这两种单倍型与来自新西兰北岛的螺类相同。由于样本的局限性，我们不能排除其中一种单倍型源自南岛的可能性，但我们的结果清楚地表明了欧洲种群源自新西兰。欧洲两种单倍型之间的显著差异意味着两个不同的线粒体谱系成功定殖，这与之前基于核标记的数据一致。