Martin Michael D, Olsen Morten Tange, Samaniego Jose A, Zimmer Elizabeth A, Gilbert M Thomas P
Centre for GeoGenetics Natural History Museum of Denmark Faculty of Science University of Copenhagen Øster Voldgade 5-71350 Copenhagen K Denmark.
Center for Theoretical Evolutionary Genomics University of California Valley Life Sciences Building Berkeley California.
Ecol Evol. 2016 May 5;6(11):3760-3771. doi: 10.1002/ece3.2143. eCollection 2016 Jun.
Common ragweed ( L.) is an invasive, wind-pollinated plant nearly ubiquitous in disturbed sites in its eastern North American native range and present across growing portions of Europe, Africa, Asia, and Australia. Phenotypic divergence between European and native-range populations has been described as rapid evolution. However, a recent study demonstrated major human-mediated shifts in ragweed genetic structure before introduction to Europe and suggested that native-range genetic structure and local adaptation might fully explain accelerated growth and other invasive characteristics of introduced populations. Genomic differentiation that potentially influenced this structure has not yet been investigated, and it remains unclear whether substantial admixture during historical disturbance of the native range contributed to the development of invasiveness in introduced European ragweed populations. To investigate fine-scale population genetic structure across the species' native range, we characterized diallelic SNP loci via a reduced-representation genotyping-by-sequencing (GBS) approach. We corroborate phylogeographic domains previously discovered using traditional sequencing methods, while demonstrating increased power to resolve weak genetic structure in this highly admixed plant species. By identifying exome polymorphisms underlying genetic differentiation, we suggest that geographic differentiation of this important invasive species has occurred more often within pathways that regulate growth and response to defense and stress, which may be associated with survival in North America's diverse climatic regions.
普通豚草（Ambrosia artemisiifolia L.）是一种靠风媒传粉的入侵植物，在其北美东部原生范围内，几乎在受干扰的地区随处可见，并且在欧洲、非洲、亚洲和澳大利亚的大部分种植区域都有分布。欧洲种群与原生范围内种群之间的表型差异被描述为快速进化。然而，最近的一项研究表明，豚草在引入欧洲之前，其遗传结构就已发生了主要由人类介导的变化，并表明原生范围内的遗传结构和局部适应性可能充分解释了引入种群的加速生长及其他入侵特性。尚未对可能影响这种结构的基因组分化进行研究，而且尚不清楚在原生范围历史干扰期间的大量混合是否促成了引入欧洲的豚草种群的入侵性发展。为了研究该物种原生范围内的精细种群遗传结构，我们通过简化代表性测序基因分型（GBS）方法对双等位基因SNP位点进行了特征分析。我们证实了先前使用传统测序方法发现的系统发育地理区域，同时证明了在这种高度混合的植物物种中解析弱遗传结构的能力有所提高。通过识别遗传分化背后的外显子多态性，我们认为这种重要入侵物种的地理分化更多地发生在调节生长以及对防御和胁迫反应的途径中，这可能与在北美多样气候区域的生存有关。
