Data from: The devil is in the details: genetic variation in introduced populations and its contributions to invasion

The influence of genetic variation on invasion success has captivated researchers since the start of the field of invasion genetics 50 years ago. We review the history of work on this question and conclude that genetic variation – as surveyed with molecular markers – appears to shape invasion rarely. Instead, there is a significant disconnect between marker assays and ecologically relevant genetic variation in introductions. We argue that the potential for adaptation to facilitate invasion will be shaped by the details of genotypes affecting phenotypes, and we highlight three areas in which we see opportunities to make powerful new insights. 1) The genetic architecture of adaptive variation. Traits shaped by large effect alleles may be strongly impacted by founder events but likely to respond to selection when genetic drift is strong. Large effect loci may be especially relevant for traits involved in biotic interactions. 2) Cryptic genetic variation exposed during invasion. Introductions have strong potential to uncover masked variation due to alterations in genetic and ecological environments. 3) Genetic interactions during admixture of multiple source populations. As divergence among sources increases, positive followed by increasingly negative effects of admixture should be expected. Though generally hypothesized to be beneficial during invasion, admixture is most often reported among sources of intermediate divergence, supporting the possibility that incompatibilities among divergent source populations might be limiting their introgression. Finally, we note that these details of invasion genetics can be coupled with comparative demographic analyses to link genetic changes to the evolution of invasiveness itself.

自50年前入侵遗传学（invasion genetics）领域创立以来，遗传变异对生物入侵成功的影响始终吸引着研究者的关注。我们对该问题的研究历程进行了系统综述，结果显示：通过分子标记（molecular markers）检测得到的遗传变异，似乎极少对入侵过程产生显著塑造作用。与之相对，入侵事件中，分子标记检测得到的遗传变异与具有生态学相关性的遗传变异之间存在显著脱节。我们认为，适应性演化助力生物入侵的潜力，将由调控表型的基因型细节所决定，并重点梳理了三个有望取得突破性新发现的研究方向：1. 适应性变异的遗传架构（genetic architecture）。由大效应等位基因（large effect alleles）调控的性状，可能会受到奠基者事件（founder events）的强烈影响，但在遗传漂变（genetic drift）作用较强的场景下，这类性状更易对自然选择作出响应；大效应基因座（loci）或许与参与生物互作的性状关联尤为紧密。2. 入侵过程中暴露的隐蔽遗传变异（cryptic genetic variation）。由于遗传与生态环境发生改变，入侵事件极有可能揭示被掩盖的遗传变异。3. 多重源种群混合（admixture）过程中的遗传互作。随着源种群间分化程度的提升，混合效应会先呈现正向促进作用，随后逐渐转为负向抑制作用。尽管学界通常假设混合对生物入侵过程有益，但现有相关报道多集中于中等分化程度的源种群之间，这支持了“分化程度较高的源种群之间可能存在生殖不相容性，进而限制其基因渐渗（introgression）”这一可能性。最后，我们提出，可将入侵遗传学的上述研究细节与比较种群人口统计学分析（comparative demographic analyses）相结合，从而将遗传变化与入侵性本身的演化过程直接关联起来。