Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, 69120, Heidelberg, Germany.
Genomics and Proteomics Core Facility, German Cancer Research Center, 69120, Heidelberg, Germany.
Commun Biol. 2021 Sep 17;4(1):1096. doi: 10.1038/s42003-021-02609-w.
The marbled crayfish (Procambarus virginalis) is a triploid and parthenogenetic freshwater crayfish species that has colonized diverse habitats around the world. Previous studies suggested that the clonal marbled crayfish population descended as recently as 25 years ago from a single specimen of P. fallax, the sexually reproducing parent species. However, the genetic, phylogeographic, and mechanistic origins of the species have remained enigmatic. We have now constructed a new genome assembly for P. virginalis to support a detailed phylogeographic analysis of the diploid parent species, Procambarus fallax. Our results strongly suggest that both parental haplotypes of P. virginalis were inherited from the Everglades subpopulation of P. fallax. Comprehensive whole-genome sequencing also detected triploid specimens in the same subpopulation, which either represent evolutionarily important intermediate genotypes or independent parthenogenetic lineages arising among the sexual parent population. Our findings thus clarify the geographic origin of the marbled crayfish and identify potential mechanisms of parthenogenetic speciation.
大理石纹螯虾（Procambarus virginalis）是一种三倍体和孤雌生殖的淡水螯虾物种，已在世界各地的各种生境中定殖。先前的研究表明，最近 25 年内，从具有性生殖能力的亲种美洲原螯虾（Procambarus fallax）的单个标本中衍生出了克隆的大理石纹螯虾种群。然而，该物种的遗传、系统地理学和机制起源仍然是个谜。我们现在已经为大理石纹螯虾构建了一个新的基因组组装，以支持对其双亲种 Procambarus fallax 的详细系统地理学分析。我们的结果强烈表明，大理石纹螯虾的两个亲本组型都是从美洲原螯虾的大沼泽地种群中遗传下来的。综合全基因组测序还在同一亚种群中检测到了三倍体标本，这些标本要么代表着进化上重要的中间基因型，要么是在有性亲种群中独立出现的孤雌生殖谱系。我们的研究结果因此阐明了大理石纹螯虾的地理起源，并确定了孤雌生殖物种形成的潜在机制。
