A growing body of research suggests that many clonal populations maintain genetic diversity even without occasional sexual reproduction. The purpose of our study was to document variation in SNP diversity, DNA content, and pathogen susceptibility in clonal lineages of the New Zealand freshwater snail, Potamopyrgus antipodarum. We studied snails that were collected from multiple field sites around a single lake (Lake Alexandrina), as well as isofemale clonal lineages that had been isolated and maintained in the laboratory. We used the KASP method to genotype our samples at 46 nuclear SNP sites, and we used flow cytometry to estimate DNA content. We found high levels of SNP diversity, both in our field samples and in our clonal laboratory lines. We also found evidence of high variation in DNA content among clones, even among clones with identical genotypes across all SNP sites. Controlled pathogen exposures of the laboratory populations revealed variation in susceptibility among distinct clonal genotypes, which was independent of DNA content. Taken together, these results show high levels of diversity among asexual snails, especially for DNA content, and they suggest rapid genome evolution in asexuals.

中文翻译：

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单个无性蜗牛种群内的 DNA 含量变异和 SNP 多样性

越来越多的研究表明，即使没有偶尔的有性繁殖，许多克隆种群也能保持遗传多样性。我们研究的目的是记录新西兰淡水蜗牛 Potamopyrgus antipodarum 克隆谱系中 SNP 多样性、DNA 含量和病原体易感性的变化。我们研究了从单个湖泊（亚历山大湖）周围多个野外地点收集的蜗牛，以及在实验室中分离和维持的同种雌性克隆谱系。我们使用 KASP 方法对 46 个核 SNP 位点的样本进行基因分型，并使用流式细胞术估计 DNA 含量。我们在我们的田间样品和我们的克隆实验室品系中都发现了高水平的 SNP 多样性。我们还发现了克隆之间 DNA 含量差异很大的证据，甚至在所有 SNP 位点具有相同基因型的克隆中。实验室人群的受控病原体暴露揭示了不同克隆基因型之间易感性的变化，这与 DNA 含量无关。综上所述，这些结果表明无性蜗牛具有高度的多样性，尤其是 DNA 含量，它们表明无性蜗牛的基因组进化速度很快。