Sequence similarities were calculated using programs of the Wisconsin Package, version 10.1 (Accelrys). Multiple sequences were aligned using the program CLUSTAL_X,version 1.8 . Phylogenetic analysis was performed using PHYLIP and MEGA. Evolutionary distances were calculated by Kimura’s two-parameter model. Phylogenetic trees were constructed by the neighbour-joining and maximum-parsimony (Fitch, 1971)methods with bootstrap values based on 1000 replications.