State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Proc Natl Acad Sci U S A. 2021 May 18;118(20). doi: 10.1073/pnas.2022302118.
How coniferous forests evolved in the Northern Hemisphere remains largely unknown. Unlike most groups of organisms that generally follow a latitudinal diversity gradient, most conifer species in the Northern Hemisphere are distributed in mountainous areas at middle latitudes. It is of great interest to know whether the midlatitude region has been an evolutionary cradle or museum for conifers and how evolutionary and ecological factors have driven their spatiotemporal evolution. Here, we investigated the macroevolution of , the largest conifer genus and characteristic of northern temperate coniferous forests, based on nearly complete species sampling. Using 1,662 genes from transcriptome sequences, we reconstructed a robust species phylogeny and reestimated divergence times of global pines. We found that ∼90% of extant pine species originated in the Miocene in sharp contrast to the ancient origin of , indicating a Neogene rediversification. Surprisingly, species at middle latitudes are much older than those at other latitudes. This finding, coupled with net diversification rate analysis, indicates that the midlatitude region has provided an evolutionary museum for global pines. Analyses of 31 environmental variables, together with a comparison of evolutionary rates of niche and phenotypic traits with a net diversification rate, found that topography played a primary role in pine diversification, and the aridity index was decisive for the niche rate shift. Moreover, fire has forced diversification and adaptive evolution of Our study highlights the importance of integrating phylogenomic and ecological approaches to address evolution of biological groups at the global scale.
针叶林如何在北半球进化在很大程度上仍是未知的。与大多数通常遵循纬度多样性梯度的生物群体不同,北半球的大多数针叶树种分布在中纬度的山区。了解中纬度地区是否一直是针叶树的进化摇篮或博物馆,以及进化和生态因素如何驱动它们的时空进化,这是非常有趣的。在这里,我们基于近乎完整的物种采样,研究了最大的针叶树种属 的宏观进化,该属是北温带针叶林的特征。我们使用来自转录组序列的 1662 个基因,重建了一个稳健的物种系统发育,并重新估计了全球松树的分化时间。我们发现,现存的松树物种中约有 90%起源于中新世,这与 的古老起源形成鲜明对比,表明中新世以来发生了新的多样化。令人惊讶的是,中纬度地区的物种比其他纬度地区的物种古老得多。这一发现,加上净多样化率分析,表明中纬度地区为全球松树提供了一个进化博物馆。对 31 个环境变量的分析,以及与净多样化率的生态位和表型特征进化率的比较,发现地形在松树多样化中起着主要作用,干旱指数对生态位率的转变起决定性作用。此外,火灾迫使 发生了多样化和适应性进化。我们的研究强调了将系统发育学和生态学方法相结合来解决全球生物群进化的重要性。