Phylogeography And Population Structure Of Betula Ermanii

The fluctuation of Quaternary climatic has profound effects on the distribution pattern and genetic structures of current species. Phylogeography provides us a convenient method to address the refugie of current species during the Quaternary. To date, the phylogeography studies in China mainly focused on the Southwestern, Southeastern and northern China, yet few studies have investigated the putative refugia of current species in northeast of China (NEC).In this study, we employed three different types of molecular markers including SSR, nuclear gene G3pdh and chloroplast DNA (trnL-F, psbK-psbI, trnH-psbA) to infer the phylogeographic pattern and genetic structure for Betula ermanii. To this end, we analyzed the genetic variability of135individuals from6populations. Accordingly, the nine SSR produced a total of137at the species level, of which38alleles were specific to different population. The obtained sequences of G3pdh generated a total of196variable sites and164haplotypes. The haplotype diversity (h) at the species level was0.996and nucleotide diversity (πτ) was0.019. It indicated that B. ermanii has high level of genetic diversity. We also noted that genetic diversity of the Changbai Mountains and Daxing’ anling populations harbor high levels of genetic diversity. In addition, analyses of the phylogenetic trees and STRUCTURE revealed that the populations of Changbai Mountains and Daxing’ anling showed obvious genetic differentiation. However, results from AMOVA based G3pdh and cpDNA revealed that most of the variations are observed within populations and FST are0.03441and0.47393. Similarly, although a large number of haplotypes were found at G3pdh, haplotypes network analysis failed to show the geographical pattern of this species. Nonetheless, the combined cpDNA sequences generated11haplotypes, and the populations of Changbai Mountain and Daxing’anling possessed relatively greater number of haplotypes.Taken together, our findings suggested that populations of Changbai Mountain and Daxing’ anling might originate from distinct glacial refuges.