Different processes shape the patterns of divergence in the nuclear and chloroplast genomes of a relict tree species in East Asia

Isolation by spatial distance (IBD), environment (IBE), and historical climatic stability (IBI) are three common processes assessed in phylogeographic and/or landscape genetic studies. However, the relative contributions of these three processes with respect to spatial genetic patterns have seldom been compared. Moreover, whether the relative contribution differ in different regions or when assessed using different genetic markers has rarely been reported. Lindera obtusiloba has been found to have two sister genetic clades of chloroplast (cpDNA) and nuclear microsatellite (nSSR), both of which show discontinuous distribution in northern and southern East Asia. In this study, we used the Mantel test and multiple matrix regression with randomization (MMRR) to determine the relative contributions of IBD, IBE, and IBI with respect to L. obtusiloba populations. Independent Mantel tests and MMRR calculations were conducted for two genetic data set (cpDNA and nSSR), and for different regions (...