Fagus L. is a key component in temperate deciduous broadleaf forests of the Northern Hemisphere. However, its biogeographic history has not been examined under the framework of a fully resolved and reasonably time-calibrated phylogeny. In this study, we sequenced 28 nuclear single/low-copy loci (18 555 bp in total) of 11 Fagus species/segregates and seven outgroups. Phylogenetic trees were reconstructed using both concatenation-based (maximum parsimony, maximum likelihood, and Bayesian inference) and coalescent-based methods (StarBEAST2, ASTRAL). The monophyly of two subgenera (Fagus and Engleriana) and most sections was well supported, except for sect. Lucida, which was paraphyletic with respect to sect. Longipetiolata. We also found a major phylogenetic conflict among North American, East Asian, and West Eurasian lineages of subgen. Fagus. Three segregates that have isolated distribution (F. mexicana, F. multinervis, and F. orientalis) were independent evolutionary units. Biogeographic analysis with fossils suggested that Fagus could have originated in the North Pacific region in late early Eocene. Major diversifications coincided with a climate aberration at the Eocene/Oligocene boundary and the global cooling since mid-Miocene. The late Miocene accelerated global cooling and the Pleistocene glaciations would have driven beeches into East Asia, North America, and West Eurasia. Meanwhile, range reduction and extinction in high latitudes, central Asia, and western North America converged to form the beech modern distribution pattern. This study provides a first attempt to disentangle the biogeographic history of beeches in the context of a nearly resolved and time-calibrated phylogeny, which could shed new insights into the formation of the temperate biome in the Northern Hemisphere.

中文翻译：

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基于 28 个核单/低拷贝位点的山毛榉 (Fagaceae) 系统发育和生物地理学

Fagus L. 是北半球温带落叶阔叶林的重要组成部分。然而，它的生物地理历史尚未在完全解决且经过合理时间校准的系统发育的框架下进行检查。在这项研究中，我们对 11 个Fagus物种/分离物和 7 个外群的 28 个核单/低拷贝基因座（总共 18 555 bp）进行了测序。系统发育树使用基于串联（最大简约、最大似然和贝叶斯推理）和基于合并的方法（StarBEAST2、ASTRAL）重建。两个亚属（Fagus和Engleriana）和大多数部分的单系得到了很好的支持，除了 sect. Lucida，与教派有关。长翅目。我们还发现了北美、东亚和西欧亚亚属谱系之间的主要系统发育冲突。法古斯。三个具有孤立分布的分离物（F. mexicana、F. multinervis和F. orientalis）是独立的进化单位。用化石进行的生物地理学分析表明，Fagus可能起源于始新世晚期晚期的北太平洋地区。主要的多样化与始新世/渐新世边界的气候异常和中新世中期以来的全球降温相吻合。中新世晚期加速了全球变冷，更新世冰川作用将山毛榉驱赶到东亚、北美和西欧亚大陆。同时，高纬度地区、中亚地区和北美西部地区的范围缩小和灭绝汇聚，形成了山毛榉现代分布格局。这项研究首次尝试在几乎解决和时间校准的系统发育的背景下解开山毛榉的生物地理历史，这可以为北半球温带生物群落的形成提供新的见解。