Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
SciLifeLab, Uppsala University, Uppsala, Sweden.
Nat Commun. 2024 Oct 14;15(1):8538. doi: 10.1038/s41467-024-52612-y.
The effect of past environmental changes on the demography and genetic diversity of natural populations remains a contentious issue and has rarely been investigated across multiple, phylogenetically distant species. Here, we perform comparative population genomic analyses and demographic inferences for seven widely distributed and ecologically contrasting European forest tree species based on concerted sampling of 164 populations across their natural ranges. For all seven species, the effective population size, N, increased or remained stable over many glacial cycles and up to 15 million years in the most extreme cases. Surprisingly, the drastic environmental changes associated with the Pleistocene glacial cycles have had little impact on the level of genetic diversity of dominant forest tree species, despite major shifts in their geographic ranges. Based on their trajectories of N over time, the seven tree species can be divided into three major groups, highlighting the importance of life history and range size in determining synchronous variation in genetic diversity over time. Altogether, our results indicate that forest trees have been able to retain their evolutionary potential over very long periods of time despite strong environmental changes.
过去环境变化对自然种群的数量和遗传多样性的影响仍然是一个有争议的问题，而且很少在多个系统发育上相距甚远的物种中进行过研究。在这里，我们对七种广泛分布且具有生态差异的欧洲森林树种进行了比较种群基因组分析和种群动态推断，这些树种是基于对其自然分布范围内的 164 个种群进行协同采样的。对于这七种物种，有效种群数量 N 在许多冰川周期中增加或保持稳定，在最极端的情况下，增加或保持稳定的时间长达 1500 万年。令人惊讶的是，与更新世冰川周期相关的剧烈环境变化对优势森林树种的遗传多样性水平几乎没有影响，尽管它们的地理范围发生了重大变化。根据 N 随时间的轨迹，这七种树种可以分为三大类，这突出了生活史和范围大小在确定遗传多样性随时间同步变化中的重要性。总的来说，我们的研究结果表明，尽管经历了强烈的环境变化，森林树木仍然能够在很长的时间内保持其进化潜力。
