Mitochondrial DNA polymorphism in the Vietnamese population

The mitochondrial DNA variation was screened in a sample of 50 unrelated in dividuals of the Vietnamese population originating from Hanoi. A combinatio n of long and standard PCR and restriction endonuclease digests with the en zymes HpaI, BamHI, HaeII, MspI, AvaII and HincII were used to reveal mtDNA variation. Twenty enzyme morphs were detected, three of which (HaeII-13(Vie t), MspI-19(Viet) and MspI-20(Viet)) are new and are produced by a single m utational event in already known enzyme morphs. Ten already known and four new mitotypes [93(Viet) (1-1-2-4-1), 94(Viet) (2-1-13(Viet)-1-1), 95(Viet) (2-1-13(Viet)-19(Viet)-1) and 96(Viet) (1-1-2-20(Viet)-12)] were found in t he Vietnamese population. The 9-bp deletion occurring in the COII/tRNA(Lys) region of the mitochondrial genome was also analysed and 10 samples were f ound to have this deletion. The comparison of the Vietnamese with other Eas t Asian populations showed a close genetic relationship of the population u nder investigation with other Orientals. However, the Vietnamese population can be differentiated by the significantly higher frequency of the enzyme morph HincII-5 and by seven new markers. These results strongly support the hypothesis of a dual ethnic origin of the Vietnamese population from the C hinese and Thai-Indonesian populations based on HLA markers and linguistic evidence.