Data from: Two colonisation stages generate two different patterns of genetic diversity within native and invasive ranges of Ulex europaeus

Genetic diversity and the way a species is introduced influence the capacity of populations of invasive species to persist in, and adapt to, their new environment. The diversity of introduced populations affects their evolutionary potential, which is particularly important for species that have invaded a wide range of habitats and climates, such as European gorse, Ulex europaeus. This species originated in the Iberian peninsula and colonised Europe in the Neolithic; over the course of the last two centuries it was introduced to, and has become invasive in, other continents. We characterised neutral genetic diversity and its structure in the native range and in invaded regions. By coupling these results with historical data we have identified the way in which gorse populations were introduced and the consequences of introduction history on genetic diversity. Our study is based on the genotyping of individuals from 18 populations at six microsatellite loci. As Ulex europaeus is an allohexaploid species, we used recently developed tools which take into account genotypic ambiguity. Our results show that genetic diversity in gorse is very high, and mainly contained within populations. We confirm that colonisation occurred in two stages. During the first stage, gorse spread out naturally from Spain towards northern Europe, losing some genetic diversity. During the second stage, gorse was introduced by humans into different regions of the world, from northern Europe. These introductions resulted in the loss of rare alleles, but did not significantly reduce genetic diversity and thus the evolutionary potential of this invasive species.

遗传多样性（Genetic diversity）与物种引入方式，共同影响入侵物种（invasive species）种群在新生境中存续并适应环境的能力。引入种群的遗传多样性会影响其进化潜力（evolutionary potential），这对于已入侵多样生境与气候类型的物种尤为关键，如欧洲荆豆（Ulex europaeus）。该物种起源于伊比利亚半岛，在新石器时代便已扩散至欧洲；近两个世纪以来，它被引入其他大陆并成为入侵物种。我们对该物种原生分布区（native range）与入侵区域的中性遗传多样性（neutral genetic diversity）及其结构进行了表征。通过将上述结果与历史数据相结合，我们明确了欧洲荆豆种群的引入路径，以及引入历史对其遗传多样性的影响。本研究基于对18个种群的个体在6个微卫星位点（microsatellite loci）上的基因分型。由于欧洲荆豆是异源六倍体（allohexaploid）物种，我们采用了新近开发的、可兼容基因型歧义（genotypic ambiguity）的分析工具。研究结果显示，欧洲荆豆的遗传多样性水平极高，且主要存在于种群内部。我们证实其扩散定植分为两个阶段：第一阶段，欧洲荆豆从西班牙自然扩散至北欧，期间丢失了部分遗传多样性；第二阶段，人类从北欧将欧洲荆豆引入全球不同地区，这类引入事件导致了稀有等位基因（rare alleles）的丢失，但并未显著降低其遗传多样性，因此未削弱该入侵物种的进化潜力。