Abstract: In this study, 11 restriction endonucleases were used to analyze the RFLP of mitochondrial DNA purified from nine species of Sphingonotus Fieber, Leptopternis gracilis which has close relationship with Sphingonotus and Calliptamus italicus which has somewhat distant relationship with Sphingonotus. We estimated the average number of nucleotide substitutions per site (genetic distance, P) among these species according to the cleavage patterns and Nei & Li's models(1979). We also constructed the molecular phylogenetic trees and studied the phylogenetic relationship by the UPGMA method. These results show that the P values among the nine species of Sphingonotus are about 0.099 to 0.146, the P values between Sphingonotus and the distant genus are about 0.113～0.226. So the divergence time among the species of Sphingonotus would be about 10～15 million years.

Key words: Sphingonotus Fieber, mitochondrial DNA variation, phylogenetic relationship