Chloroplast DNA diversity in Castanopsis hystrix populations in south China

Nineteen Chinese populations of Castanopsis hystrix were examined to quantify genetic diversity and genetic structure at chloroplast DNA. Microsatellites (SSR) were analyzed by PCR using conserved primers. The average within population gene diversity (HS), the total gene diversity (HT), and the differentiation for unordered alleles (GST) and for ordered alleles (NST) were measured. Fourteen different haplotypes were detected, two of them very common. The level of differentiation among populations (GST = 23.6%) indicates a highly efficient seed dispersal mechanism. In addition, the difference between GST and NST for the species is not significant, suggesting that the phylogeographic structure is weak or absent. The geographical pattern of C. hystrix haplotypes could be attributed to its migration from the numerous and scattered refugia, where the species confined during the last glacial period. These results provide an important insight into patterns of postglacial recolonization of this tree species.