Weedy dandelions have a worldwide distribution and thrive in urban environments despite a lack of sexual reproduction throughout most of its range. North American dandelions, introduced from Eurasia, are believed to be primarily, if not exclusively, apomictic triploids. In some European populations, apomicts co-occur with diploid sexual individuals and hybridizations can create genetically unique apomicts, which may subsequently disperse and establish new populations globally. Using six nuclear microsatellite markers and a cpDNA intergenic spacer, we investigate the impact of this unusual natural history on population structure and diversity in three urban Boston area dandelion populations. Our results show high levels of genetic diversity within populations, spatial population structure, and seasonal genotypic differentiation in flowering times. We find evidence that sexual reproduction and recombination, presumably in Europe, and extensive gene flow drive these patterns of diversity and create the appearance of panmixia despite the lack of evidence for local sexual reproduction.

中文翻译：

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波士顿地区三个种群（蒲公英属）杂草蒲公英的种群结构、季节性基因型分化和克隆多样性

尽管在其大部分范围内缺乏有性繁殖，但杂草蒲公英在全球范围内分布并在城市环境中茁壮成长。从欧亚大陆引进的北美蒲公英被认为主要是（如果不是唯一的）无融合生殖三倍体。在一些欧洲种群中，无融合生殖体与二倍体有性个体同时发生，杂交可以产生遗传上独特的无融合生殖体，随后可能会在全球范围内分散并建立新的种群。我们使用六个核微卫星标记和一个 cpDNA 基因间隔区，研究了这种不寻常的自然历史对波士顿地区三个城市蒲公英种群的种群结构和多样性的影响。我们的研究结果表明，种群内的高水平遗传多样性、种群空间结构和开花时期的季节性基因型分化。