Department of Evolution and Ecology, University of California, Davis, CA, USA.
Department of Biology, Jacksonville State University, Jacksonville, AL, USA.
Commun Biol. 2021 Feb 5;4(1):160. doi: 10.1038/s42003-020-01632-7.
Extant conifer species may be susceptible to rapid environmental change owing to their long generation times, but could also be resilient due to high levels of standing genetic diversity. Hybridisation between closely related species can increase genetic diversity and generate novel allelic combinations capable of fuelling adaptive evolution. Our study unravelled the genetic architecture of adaptive evolution in a conifer hybrid zone formed between Pinus strobiformis and P. flexilis. Using a multifaceted approach emphasising the spatial and environmental patterns of linkage disequilibrium and ancestry enrichment, we identified recently introgressed and background genetic variants to be driving adaptive evolution along different environmental gradients. Specifically, recently introgressed variants from P. flexilis were favoured along freeze-related environmental gradients, while background variants were favoured along water availability-related gradients. We posit that such mosaics of allelic variants within conifer hybrid zones will confer upon them greater resilience to ongoing and future environmental change and can be a key resource for conservation efforts.
现存的针叶树种由于其较长的世代时间，可能容易受到快速的环境变化的影响，但由于高水平的遗传多样性，它们也可能具有弹性。亲缘关系密切的物种之间的杂交可以增加遗传多样性，并产生新的等位基因组合，从而推动适应性进化。我们的研究揭示了在由白皮松和油松形成的针叶树杂交区中适应性进化的遗传结构。通过采用一种多方面的方法，强调连锁不平衡和祖先富集的空间和环境模式，我们确定了最近渗入的和背景的遗传变异体，这些变异体驱动着沿着不同环境梯度的适应性进化。具体来说，来自油松的最近渗入的变异体在与冻结相关的环境梯度上受到青睐，而背景变异体在与水分供应相关的梯度上受到青睐。我们假设，这种针叶树杂交区内的等位基因变异镶嵌体将赋予它们对持续和未来环境变化更大的弹性，并且可以成为保护努力的关键资源。
