Phylogeography and genetic structure of a Tertiary relict tree

The phylogeography, the study of the spatial and temporal history of a species, remains largely unclear for plant species in sub-tropical China. Zhang et al. use Tapiscia sinensis, an endemic tree species, as a model to study the phylogeographical history and patterns of genetic diversity of Tertiary relict species in subtropical regions.

Samples were taken from 24 populations covering the natural geographical distribution of T. sinensis. Genetic structure was investigated by analysis of molecular variance (AMOVA) and spatial analysis of molecular variance (SAMOVA). Phylogenetic relationships among haplotypes were constructed with maximum parsimony and haplotype network methods. Historical population expansion events were tested with pairwise mismatch distribution analysis and neutrality tests. Species potential range was deduced by ecological niche modelling (ENM).

They find low within-population diversity as well as strong genetic differentiation, and historical demography analyses suggest recent population expansion. The existence of multiple montane refugia for T. sinense during the last glacial maximum is inferred in central and western China.