Phylogenomic and ecological analyses reveal the spatiotemporal evolution of global pines

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 mid-latitude 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 Pinus, 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 the first robust species phylogeny and re-estimated divergence times of global pines. We found that approximately 90% of extant pine species originated in the Miocene in sharp contrast to the ancient origin of Pinus, indicating a Neogene re-diversification. Surprisingly,...北半球针叶林的演化历程迄今仍未被完全阐明。与多数遵循纬度多样性格局（latitudinal diversity gradient）的生物类群不同，北半球的多数针叶树物种均分布于中纬度山地之中。学界一直颇为关注的问题是，中纬度地区是否为针叶树的演化摇篮或演化博物馆，以及演化与生态因子如何推动了它们的时空演化。本研究以近乎全面的物种采样为基础，针对松属（Pinus）——北半球温带针叶林的代表性类群、全球最大的针叶树属——开展了宏演化（macroevolution）研究。本研究利用转录组序列（transcriptome sequences）中的1662个基因，构建了首个高置信度的物种系统发育树，并重新估算了全球松树的分化时间（divergence times）。研究发现，尽管松属起源古老，但约90%的现存松树物种均形成于中新世（Miocene），这表明松属在新近纪（Neogene）发生了一次显著的再辐射演化。令人意外的是，……