Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada.
Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada.
Evolution. 2022 Sep;76(9):1953-1970. doi: 10.1111/evo.14582. Epub 2022 Aug 1.
Polyploidy is a significant component in the evolution of many taxa, particularly plant groups. However, new polyploids face substantial fitness disadvantages due to a lack of same-cytotype mates, and the factors promoting or preventing polyploid establishment in natural populations are often unclear. We develop spatially explicit agent-based simulation models to test the hypothesis that a perennial life history and clonal propagation facilitate the early stages of polyploid establishment and persistence. Our models show that polyploids are more likely to establish when they have longer life spans than diploids, especially when self-fertilization rates are high. Polyploids that combine sexual and clonal reproduction can establish across a wide range of life histories, but their success is moderated by clonal strategy. By tracking individuals and mating events, we reveal that clonal architecture has a substantial impact on the spatial structure of the mixed diploid-polyploid population during polyploid establishment: altering patterns of mating within or between cytotypes via geitonogamous self-fertilization, the mechanisms through which polyploid establishment proceeds, and the final composition of the polyploid population. Overall, our findings provide novel insight into the role of clonal structure in modulating the complex relationship between polyploidy, perenniality, and clonality and offer testable predictions for future empirical work.
多倍体是许多分类群(尤其是植物类群)进化的重要组成部分。然而,由于缺乏同型交配体,新的多倍体面临着相当大的适应度劣势,而促进或阻止自然种群中多倍体建立的因素通常并不清楚。我们开发了具有空间显式的基于主体的模拟模型,以检验以下假设:多年生生活史和克隆繁殖有助于多倍体建立和持续的早期阶段。我们的模型表明,当多倍体的寿命比二倍体长时,它们更有可能建立,尤其是当自交率较高时。结合有性和克隆繁殖的多倍体可以在广泛的生活史范围内建立,但它们的成功受到克隆策略的调节。通过跟踪个体和交配事件,我们揭示了克隆结构对多倍体建立过程中混合二倍体-多倍体种群的空间结构有重大影响:通过同型自交改变了胞型内或胞型间的交配模式,这是多倍体建立的机制,以及多倍体种群的最终组成。总的来说,我们的研究结果为克隆结构在调节多倍体、多年生性和克隆性之间复杂关系中的作用提供了新的见解,并为未来的实证工作提供了可检验的预测。