RESUMEN
The distribution of 30 HLA-DRB1 alleles in 85 individuals and of 10 HLA-DQB1 alleles in 91 individuals of the Viet Muong population was studied and compared with those of nine other Asian populations, including 103 Viet Kinh belonging to the major ethnic group in Vietnam. In terms of genetic distance, our data are consistent with a close ethnogeographic relationship between Viet Muong, Buyi and Dai Lue, two Southern Chinese ethnic groups. Conversely, these three populations are distant from the Northern Chinese population. The Viet Kinh belong to an intermediate group, together with North-eastern Thais, Thais and present day Thais. The striking presence of the HLA-DQ1*0502 allele (48% frequency) in the Viet Muongs is possibly anthropological or environmental in origin: the Viet Muongs have been submitted to endemic malaria for centuries, and the survivors carry the protective trait of glucose-6-phosphate dehydrogenase deficiency. This raises the hypothesis of a possible resistance to lethal or severe forms of the disease, where the association with a specific HLA-DQB1 allele may play a role.
Asunto(s)
Antígenos HLA-DQ/genética , Antígenos HLA-DR/genética , Malaria/genética , Alelos , Frecuencia de los Genes , Cadenas beta de HLA-DQ , Cadenas HLA-DRB1 , Humanos , Desequilibrio de Ligamiento , Malaria/inmunología , Polimorfismo Genético , VietnamRESUMEN
The mitochondrial DNA variation was screened in a sample of 50 unrelated individuals of the Vietnamese population originating from Hanoi. A combination of long and standard PCR and restriction endonuclease digests with the enzymes HpaI, BamHI, HaeII, MspI, AvaII and HincII were used to reveal mtDNA variation. Twenty enzyme morphs were detected, three of which (HaeII-13Viet, MspI-19Viet and MspI-20Viet) are new and are produced by a single mutational event in already known enzyme morphs. Ten already known and four new mitotypes [93Viet (1-1-2-4-1), 94Viet (2-1-13Viet-1-1), 95Viet (2-1-13Viet-19Viet-1) and 96Viet (1-1-2-20Viet-12)] were found in the Vietnamese population. The 9-bp deletion occurring in the COII/tRNALys region of the mitochondrial genome was also analysed and 10 samples were found to have this deletion. The comparison of the Vietnamese with other East Asian populations showed a close genetic relationship of the population under 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 Chinese and Thai-Indonesian populations based on HLA markers and linguistic evidence.
Asunto(s)
ADN Mitocondrial/genética , Etnicidad/genética , Polimorfismo Genético , China/etnología , Frecuencia de los Genes , Antígenos HLA/genética , Humanos , Indonesia/etnología , Lenguaje , Mutación , Filogenia , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Tailandia/etnología , VietnamRESUMEN
We report here the DNA polymerase chain reaction sequence-specific oligonucleotide (PCR-SSO) typing of the HLA-DR B1, B3, B4, B5 and DQB1 loci for a sample of 103 Vietnamese Kinh from Hanoi, and compare their allele and haplotype frequencies to other East Asiatic and Oceanian populations studied during the 11th and 12th International HLA Workshops. The Kinh exhibit some very high-frequency alleles both at DRB1 (1202, which has been confirmed by DNA sequencing, and 0901) and DQB1 (0301, 03032, 0501) loci, which make them one of the most homogeneous population tested so far for HLA class II in East Asia. Three haplotypes account for almost 50% of the total haplotype frequencies in the Vietnamese. The most frequent haplotype is HLA-DRB1*1202-DRB3*0301-DQB1*0301 (28%), which is also predominant in Southern Chinese, Micronesians and Javanese. On the other hand, DRB1*1201 (frequent in the Pacific) is virtually absent in the Vietnamese. The second most frequent haplotype is DRB1*0901-DRB4*01011-DQB1*03032 (14%), which is also commonly observed in Chinese populations from different origins, but with a different accessory chain (DRB4*0301) in most ethnic groups. Genetic distances computed for a set of Asiatic and Oceanian populations tested for DRB1 and DQB1 and their significance indicate that the Vietnamese are close to the Thai, and to the Chinese from different locations. These results, which are in agreement with archaeological and linguistic evidence, contribute to a better understanding of the origin of the Vietnamese population, which has until now not been clear.