Abstract
We used inter-simple sequence repeat (ISSR) markers to investigate genetic variation in eight natural populations of Elephantopus scaber from South China, including Guangdong, Hainan and Hong Kong. Eleven primers produced 247 bands across all 184 individuals, of which 243 (98.4%) were polymorphic. The average genetic diversity at the species and population levels was estimated to be 0.283 and 0.103, respectively, using mean expected heterozygosity. The average gene differentiation (F ST) among populations was 0.725. AMOVA analysis showed that the partition of molecular variation between and within populations was 72.5% and 27.5%, respectively. The effective number of migrants among populations based on the F ST was relatively low (N m = 0.095). Cluster analysis based on Nei's genetic distance and the neighbour-joining method revealed the genetic relationships among the populations of E. scaber. The Mantel test indicated that there was no significant correlation between population genetic and geographic distances. The results obtained from the AMOVA analysis, the cluster analysis, and the Mantel test all suggested that fragmented local environments and human disturbance might play important roles in shaping the population structure of E. scaber.
Acknowledgements
We would like to thank Dr Tongshui Zhou and Dr Hui Cao for fieldwork, Dr Yidong Lei for data analysis, and Dr Bruce C. Anderson for critical reading of the manuscript. This work was partially supported by the Chinese National Key Project for Basic Research (973) (2002CB512801), the National Natural Science Foundation of China (30570109) and the program for NCET in the University.