Data from: Long live the alien: is high genetic diversity a pivotal aspect of crested porcupine (Hystrix cristata) long-lasting and successful invasion?

Studying the evolutionary dynamics of an alien species surviving and continuing to expand after several generations can provide fundamental information on the relevant features of clearly successful invasions. Here, we tackle this task by investigating the dynamics of the genetic diversity in invasive crested porcupine (Hystrix cristata) populations, introduced to Italy about 1500 years ago, which are still growing in size, distribution range and ecological niche. Using genome-wide RAD markers, we describe the structure of the genetic diversity and the demographic dynamics of the H. cristata invasive populations and compare their genetic diversity with that of native African populations of both H. cristata and its sister species, H. africaeaustralis. First, we demonstrate that genetic diversity is lower in both the invasive Italian and the North Africa source range relative to other native populations from Sub-Saharan and South Africa. Second, we find evidence of multiple introduction events in the invasive range followed by very limited gene flow. Through coalescence-based demographic reconstructions, we also show that the bottleneck at introduction was mild and did not affect the introduced genetic diversity. Finally, we reveal that the current spatial expansion at the northern boundary of the range is following a leading-edge model characterized by a general reduction of genetic diversity towards the edge of the expanding range. We conclude that the level of genome-wide diversity of H. cristata invasive populations is less important in explaining its successful invasion than species-specific life-history traits or the phylogeographic history in the native source range.

研究外来物种历经多代繁衍仍可存活并持续扩张的演化动态，可为解析成功生物入侵的核心特征提供基础性研究依据。本研究以约1500年前被引入意大利、目前仍在种群规模、分布范围与生态位维度持续扩张的入侵性冠豪猪（Hystrix cristata）种群为研究对象，解析其遗传多样性动态。基于全基因组限制性酶切位点相关DNA（Restriction-site Associated DNA, RAD）标记，我们刻画了冠豪猪入侵种群的遗传多样性结构与种群动态，并将其遗传多样性与非洲本土的冠豪猪及其姊妹物种非洲南部豪猪（H. africaeaustralis）的本土种群进行对比。首先，研究表明，相较于撒哈拉以南非洲与南非的本土种群，入侵意大利的冠豪猪种群以及源自北非的源种群的遗传多样性均更低。其次，我们发现入侵区域存在多次引入事件，且后续基因交流极为有限的相关证据。通过基于溯祖理论的种群历史重建分析，我们进一步证实，引入时所经历的种群瓶颈效应较弱，并未对引入的遗传多样性造成显著影响。最后，我们揭示出当前该种群在分布范围北界的空间扩张遵循前沿扩张模型，即扩张范围边缘的遗传多样性普遍呈现下降趋势。本研究最终得出结论：相较于冠豪猪的物种特异性生活史特征或本土源种群的系统地理历史，其入侵种群的全基因组多样性水平并非解释其成功入侵的关键因素。