ELECTROPHORETIC STUDY ON THE PHYLOGENETIC-RELATIONSHIPS OF SOME SPECIES OF PENAEUS AND METAPENAEUS (DECAPODA, PENAEIDAE) FROM THE SOUTH CHINA SEA

Electrophoretic analysis of 17 loci coding for 15 enzymes was used to investigate the genetic variation and relationships among 7 species of Penaeus and 3 species of Metapenaeus from the South China Sea. The pr oportion of polymorphic loci (P-0.95) ranges from 0.059-0.235 and obse rved heterozygosity from 0.007-0.049, indicating low genetic variabili ty in the shrimps. The phenetic dendrogram based on Nei's genetic dist ance comprises 2 clusters, one consisting of species of Penaeus and th e other species of Metapenaeus. Among Metapenaeus, M. affinis and M. e nsis are more closely related to each other than to M. joyneri. Among Penaeus, P. (Penaeus) monodon and P. (P.) semisulcatus are closely rel ated. P. (Fenneropenaeus) merguiensis and P. (F.) penicillatus are als o closely related, but P. (F.) chinensis is more related to species of the subgenus Penaeus than to the other species of Fenneropenaeus. P. (Marsupenaeus) japonicus and P. (Melicertus) latisulcatus cluster toge ther. The large distance value between these 2 species supports their subgenus separation. The results of this study show that the current s ubgeneric division of Penaeus appears to be a natural one.