Data from: Genetic structure reveals a history of multiple independent origins followed by admixture in the allopolyploid weed Salsola ryanii

It has recently become clear that many invasive species have evolved in situ via hybridization or polyploidy from progenitors which themselves are introduced species. For species formed by hybridization or polyploidy, genetic diversity within the newly formed species is influenced by the number of independent evolutionary origins of the species. For recently formed species, an analysis of genetic structure can provide insight into the number of independent origin events involved in the formation of the species. For a putative invasive allopolyploid species, the number of origins involved in the species formation, the genetic diversity present within these origins and the level of gene flow between independent origins determines the genetic composition of the neospecies. Here we analyze the genetic structure of the newly formed allopolyploid species, Salsola ryanii, a tumbleweed which evolved within the last 20-100 years in California. We utilize the genetic structure analysis to determine that this new species is the result of at least three independent allopolyplodization events followed by gene flow between the descendants of independent origins.近期研究证实，诸多外来入侵物种可通过杂交（hybridization）或多倍化（polyploidy）在原地（in situ）完成演化，其祖先类群本身即为外来引入物种。针对通过杂交或多倍化形成的物种，新形成物种的遗传多样性（genetic diversity）取决于该物种独立演化起源的次数。对于新近形成的物种，遗传结构（genetic structure）分析可助力研究者揭示其形成过程中涉及的独立起源事件数量。对于推定的入侵性异源多倍体（allopolyploid）物种而言，其形成过程中涉及的起源次数、各起源事件内的遗传多样性，以及独立起源后代间的基因流（gene flow）水平，共同决定了该新物种的遗传组成。本研究对新近形成的异源多倍体物种*Salsola ryanii*的遗传结构展开分析，该物种是一种于过去20至100年间在加利福尼亚州演化形成的风滚草。通过遗传结构分析，我们确定该新物种至少由三次独立的异源多倍化（allopolyploidization）事件形成，且各独立起源的后代间存在基因交流。