Data from: Genetic patterns across an invasion's history: a test of change versus stasis for the Eurasian round goby in North America

Biological invasions comprise accidental evolutionary experiments, whose genetic compositions underlie relative success, spread, and persistence in new habitats. However, little is known about whether, or how, their population genetic patterns change temporally and/or spatially across the invasion's history. Theory predicts that most would undergo founder effect, exhibit low genetic divergence across the new range, and gain variation over time via new arriving propagules. To test these predictions, we analyze population genetic diversity and divergence patterns of the Eurasian round goby Neogobius melanostomus across the two decades of its North American invasion in the Laurentian Great Lakes, comparing results from 13 nuclear DNA microsatellite loci and mitochondrial DNA cytochrome b sequences. We test whether “genetic stasis”, “genetic replacement”, and/or “genetic supplement” scenarios have occurred at the invasion's core and expansion sites, in comparison to its primary native source population in the Dnieper River, Black Sea. Results reveal pronounced genetic divergence across the exotic range, with population areas remaining genetically distinct and statistically consistent across two decades, supporting “genetic stasis” and “founder takes most”. The original genotypes continue to predominate, whose high population growth likely outpaced the relative success of later arrivals. The original invasion core has stayed the most similar to the native source. Secondary expansion sites indicate slight allelic composition convergence towards the core population over time, attributable to some early “genetic supplementation”. The geographic and temporal coverage of this investigation offers a rare opportunity to discern population dynamics over time and space in context of invasion genetic theory versus reality.

生物入侵本质上属于偶然发生的进化实验，其遗传组成决定了入侵物种在新栖息地中能否取得相对成功、实现扩散并持续存续。然而，目前学界对入侵种群的群体遗传模式是否会随入侵历程在时间和/或空间维度上发生改变，以及具体的改变方式，仍知之甚少。
相关理论预测，多数入侵种群会经历奠基者效应（founder effect），在新生境范围内表现出较低的遗传分化，并随着时间推移通过新抵达的繁殖体（propagules）获得遗传变异。
为验证上述理论预测，本研究针对欧亚黑口新𫚥虎（Neogobius melanostomus）在北美圣劳伦斯五大湖（Laurentian Great Lakes）入侵的二十年间的群体遗传多样性与分化模式展开分析，基于13个核DNA微卫星位点（microsatellite loci）与线粒体DNA细胞色素b（cytochrome b）序列的检测结果进行对比。本研究以其原生境黑海（Black Sea）第聂伯河（Dnieper River）的主要源种群作为参照，检验入侵核心区与扩张区域是否出现了“遗传稳态（genetic stasis）”、“遗传替代（genetic replacement）”或“遗传补充（genetic supplement）”这三种情景。
研究结果显示，入侵外来种群在新生境范围内呈现出显著的遗传分化，且各区域种群的遗传特征在二十年间始终保持显著差异且统计学上稳定，这一结果支持“遗传稳态”与“奠基者占据主导（founder takes most）”的理论推断。原始基因型仍占据主导地位，其快速的种群增长速度很可能超过了后续迁入个体的相对定植成功率。
最初形成的入侵核心区与原生源种群的遗传相似度始终最高。
后续扩张区域的种群则随时间推移，其等位基因组成逐渐向核心区种群产生微弱趋同，这一现象可归因于早期发生的“遗传补充”事件。
本研究的地理与时间覆盖范围，为在入侵遗传学理论与实际观测的对照框架下解析种群动态的时空变化提供了难得的契机。