1
Climatic and soil factors shape the demographical history and genetic diversity of a deciduous oak ( Quercus liaotungensis ) in Northern China 1* 2 3 1 1* Jia Yang , Lucía Vázquez , Li Feng , Zhanlin Liu and Guifang Zhao 1 College of Life Sciences, Northwest University, Xi'an, Shaanxi Province, China 2 Biology Department, University of Illinois at Springfield, Springfield, Illinois, USA 3 School of Pharmacy, Xi'an Jiaotong University, Xi'an, Shaanxi Province, China Introduction Past and current climatic changes have affected the demographical history, genetic diversity and structure of temperate species. However, few researches have focused on tree species from Northern China. Here, we integrated genetic information from four chloroplast and two functional nuclear sequences, coalescent-based simulations and ecological niche modeling to reconstruct demography of Quercus liaotungensis , a dominant deciduous tree species in Northern China. Potential associations between temporal genetic variations and ecological factors were estimated for this mountainous oak species. Results Methods v 105 samples from 21 populations were sequenced; v Genetic structure was estimated using Neighbor-Net and Bayesian methods; v Demography was reconstructed with coalescent-based Approximate Bayesian Computation and ecological niche modeling (ENMs); v Correlation analysis was inferred with multiple linearregressions. v Multiple genetic loci indicated two phylogenetic clusters adapting to different temperature and precipitation seasonality among 21 populations; v Both demographical reconstruction and ENMs suggested an expansion-decline trend of Q. liaotungensis during the Quaternary climatic oscillations; v One of the functional nuclear genes showed significant relationships between genetic diversity and bioclimatic and soil conditions (e.g. temperature seasonality, precipitation of driest quarter, and soil pH). Conclusion Our results suggest that climatic oscillations during the Pleistocene have greatly affected the effective population sizes and genetic structure of Q. liaotungensis . Variations of ecological factors seem to be more important in sharping the genetic diversity and structure of this oak species. Funding: National Natural Science Foundation of China (31770229)
