A preliminary study of genetic variation in the endangered, Chinese endemic species Dysosma versipellis (Berberidaceae)

This study represents a preliminary analysis of allozyme variation in Dysosma versipellis (Berberidaceae), an endangered plant species endemic to China. Five populations of D. versipellis and one population of D. pleiantha were sampled and analyzed using starch gel electrophoresis of nine enzymes that corresponded to nine interpretable loci. Levels of genetic polymorphism within populations (means: P = 15.54%, A = 1.16, He = 0.045) were much smaller than values for seed plants in general (P = 34.2%, A = 1.53, He = 0.113), as well as values for other endemic species (P = 26.3%, A = 1.39, He = 0.063). Mean values for the FST across all D. versipellis populations tended to be high (FST = 0.468). An indirect estimate of the number of migrants per generation (Nm = 0.284) indicated that gene flow is low among populations of D. versipellis. Additionally, analysis of genetic variation revealed a substantial heterozygosity deficiency in all analyzed populations except HB. Genotype frequencies within D. versipellis populations indicate that they may be severely inbred, making inbreeding depression a possible explanation for the low seed set observed in this species. Likewise, the low level of genetic diversity observed within D. versipellis populations suggests that clonal reproduction might be more important than sexual reproduction for D. versipellis. In comparison, genetic variation observed in one population of the closely related species D. pleiantha was much higher than the variation within D. versipellis populations. On the basis of these observations, we suggest that in situ conservation will be an important and practical measure for maintaining this species. If ex situ conservation is pursued, sampling should cover all populations across the species' distribution so as to retain as much genetic diversity as possible.