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.

近期研究表明，诸多外来入侵物种可通过杂交（hybridization）或多倍化（polyploidy），由本身为外来引入物种的祖先类群就地演化而来。对于由杂交或多倍化形成的物种而言，新形成物种的遗传多样性（genetic diversity）受该物种独立演化起源的数量影响。针对新近形成的物种，遗传结构（genetic structure）分析可揭示其形成过程中涉及的独立起源事件数目。对于疑似入侵性异源多倍体（allopolyploid）物种，其形成过程中涉及的起源数量、各起源内的遗传多样性，以及独立起源种群间的基因流（gene flow）水平，共同决定了该新种（neospecies）的遗传组成。本研究针对新近形成的异源多倍体新种——加利福尼亚州近20至100年内演化而来的风滚草（tumbleweed）瑞安盐生草（Salsola ryanii）的遗传结构展开分析，通过遗传结构分析确定该新物种至少起源于三次独立的异源多倍化事件，且独立起源的后代种群间存在基因交流。