Two STR loci polymorphisms of adenosine deaminase gene in Japanese population

Polymorphism of two tetranucleotide tandem repeat loci in the adenosine deaminase (ADA) gene was studied in a Japanese population. A TAAA repeat at approximately 1100 nucleotide 5′ to the ADA transcription initiation site, and a TTTA repeat within intron 3 of the ADA gene were characterized using the polymerase chain reaction (PCR) and sequence analysis. Among the 235 individuals studied, seventeen genotypes at the ADA-TAAA locus and ten genotypes at the ADA-TTTA locus were identified, yielding discrimination potentials of 0.90 and 0.66, respectively. The observed and expected genotype values are consistent with Hardy-Weinberg equilibrium. The allele frequencies in the Japanese population were compared with the reported values for other populations. At the ADA-TAAA locus, there were significant differences between the Japanese population and an American Caucasian sample. At the ADA-TTTA locus, no significant differences were observed between Japanese and Chinese or between Japanese and Basques, but significant differences were found between our Japanese population and Italians and Mossi.