Isozymes Variation of Clarias macrocephalus from Four Locations in Thailand

Fourteen enzymes or protein were assayed in four natural populations of Clarias macrocephalus collected from different parts of Thailand; north (Chiangrai), central (Prachinburi) and south (Pattani and Yala). Starch-gel electrophoresis followed by histochemical staining were conducted and resulted in 19 loci resolved. Twelve loci (sAAT*, GAPDH-1*, 2*, IDHP*, LDH-1*, 2*, sMDH-1*, ME-1, 2*, GPI*, MPI* and PROT*) were monomorphic while seven of them were polymorphic which included EST*, FH*, sMDH-2*, ME-3*, PGM*, PGDH* and sSOD*. Observed heterozygosity were 0.080, 0.076, 0.038 and 0.050 respective to Chiangrai, Prachinburi, Pattani and Yala population. Genetic distance revealed two population groups, which were Chiangrai-Prachinburi and Pattani-Yala group and genetic distance was larger within the first group than those within the second group.