Phylotranscriptomics reveal the complex evolutionary and biogeographic history of the genus Tsuga with an East Asian-North American disjunct distribution

• Main Authors: Feng, Yuan-Yuan, Shen, Ting-Ting, Shao, Cheng-Cheng, Du, Hong, Ran, Jin-Hua, Wang, Xiao-Quan
• Format: Dataset
• Language: unknown
• Published: 2021
• Subjects: Bering Land Bridge
• Online Access: https://zenodo.org/record/4588033; https://doi.org/10.5061/dryad.12jm63xwh

The disjunct distribution between East Asia and North America is one of the best established biogeographic patterns. A robust phylogeny is fundamental for understanding the biogeographic histories of taxa with this distribution pattern. Tsuga (hemlock) is a genus of Pinaceae with a typical intercontinental disjunct distribution in East Asia and eastern and western North America, and its phylogeny has not been completely reconstructed in previous studies. In this study, we reconstructed a highly resolved phylogeny of Tsuga using 881 nuclear genes, 60 chloroplast genes and 23 mitochondrial genes and explored its biogeographic and reticulate evolutionary history. The results of phylogenetic analysis, molecular dating and ancestral area reconstruction indicate that Tsuga very likely originated from North America in the late Oligocene and dispersed from America to East Asia via the Bering Land Bridge during the middle Miocene. In particular, we found complex reticulate evolutionary pattern among the East Asian hemlock species. Tsuga sieboldii possibly originated from hybridization with the ancestor of Tsuga chinensis from mainland China and Tsuga forrestii as the paternal donor and the ancestor of Tsuga diversifolia and Tsuga ulleungensis as the maternal donor. T. chinensis (Taiwan) could have originated by hybridization together with T. sieboldii and then evolved independently after dispersal to the Taiwan Island, subsequently experiencing mitochondrial DNA introgression with T. chinensis from mainland China. Moreover, our study found that T. chinensis from western China is more closely related to T. forrestii than to T. chinensis from eastern China. The nonmonophyletic T. chinensis needs taxonomic reconsideration. Funding provided by: Chinese Academy of SciencesCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100002367Funding provided by: Ministry of Science and Technology of the People's Republic of ChinaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100002855