Allele and haplotype frequencies of the human leukocyte antigens (HLA) were studied in the Kinh Vietnamese population. We analyzed 170 unrelated healthy individuals. DNA-based HLA typing was performed using a microsphere-based array genotyping platform with sequence-specific oligonucleotide probes to distinguish HLA-A, -B, -C, -DRB1 and -DQB1 alleles. A total of 21 HLA-A, 37 HLA-B, 18 HLA-C, 25 HLA-DRB1, and 14 HLA-DQB1 alleles were identified. HLA-A*1101, A*2402, A*3303, B*1502, B*4601, Cw*0102, Cw*0702, Cw*0801, DRB1*1202, DQB1*0301, DQB1*0303, and DQB1*0501 were found with frequencies higher than 10%. Two representative haplotypes bearing two to five HLA loci were A*1101-B*1502 and A*3303-B*5801 for HLA-A-B; Cw*0801-B*1502 and Cw*0102-B*4601 for HLA-C-B; B*1502-DRB1*1202 and B*4601-DRB1*0901 for HLA-B-DRB1; DRB1*1202-DQB1*0301 and DRB1*0901-DQB1*0303 for HLA-DRB1-DQB1; A*1101-Cw*0801-B*1502 and A*3303-Cw*0302-B*5801 for HLA-A-C-B; A*1101-B*1502-DRB1*1202 and A*2901-B*0705-DRB1*1001 for HLA-A-B-DRB1, A*1101-Cw*0801-B*1502-DRB1*1202-DQB1*0301 and A*2901-Cw*1505-B*0705-DRB1*1001-DQB1*0501 for HLA-A-C-B-DRB1-DQB1. Allele distribution and haplotype analysis demonstrated that the Vietnamese population shares HLA patterns with southern Chinese, Thai, Javanese and Micronesians, while it also retains unique characteristics.

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JC virus (JCV) strains worldwide can be classified into various genotypes based on DNA sequence variations. To define the domains of the four major JCV genotypes in Asia, we collected urine samples at six unstudied sites: three in southeastern Asia, two in the central highlands and one in central Asia. DNA was extracted from urine samples, and used to amplify a 610-bp region of the viral genome. For each geographical site, we determined 16 to 31 sequences, from which a phylogenetic tree was constructed to unambiguously classify detected JCV isolates into distinct genotypes. From JCV genotype profiles at the sites studied here and elsewhere, the following conclusions were drawn. Although Af2 is the major genotype in Africa, this genotype also occurs in western and central Asia. B1-b mainly occurs in western and central Asia, including the central highlands. CY occurs in northeastern Asia with the southern boundary between China and southeast Asian countries. Although SC predominates in southeastern Asia, it also occurs in northern and central Asia at lower frequencies. In addition, a few minor JCV genotypes (B1-a, B2 and B3) occur at many sites. We discuss here the anthropological and medical significance of the present findings.

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A new method of screening type IIG restriction modification (RM) enzyme has been developed using REBASE, a database of all known and putative restriction enzymes and methyltransferases found throughout the bacterial genome sequences available in GENBANK. The in silico analysis of a group of putative type IIG RM enzymes in Microcystis aeruginosa showed a high sequence homology at both ends. This peculiarity allows for primers designing that can be used in polymerase chain reaction (PCR) to amplify the corresponding genes out of one environmental DNA extracted from a cyanobacteria-rich sample. PCR products were cloned into the pSAPV6 vector. Among eight recombinant DNA sequenced, five showed different sequences in the protein regions that interact specifically with DNA.". These five recombinant proteins expressed type IIG RM enzyme activity. Their specificities were determined, and all correspond to new DNA recognition sites.