Genetic frequency of alcohol dehydrogenase (ADH2) among three sub- populations of Southern Thais : An amplified product length polymorphism (APLP) analysis

Kusumarn Noipha, Scientist, D. of Biomedical Science, F. of Medicine, PSU.
Suvina Ratanachaiyavong, D. of Biomedical Science, F. of Medicine, PSU.
Corresponding e-mail : rsuvina@ratree.psu.ac.th

Grant : Faculty of Medicine, PSU.
Presented : The 16th Annual Academic Meeting, Faculty of Medicine, PSU, Hat Yai, Songkhla, 16-18 August 2000
Key words : alcohol dehydrogenase (ADH2), amplified product length polymorphism, Southern Thais

Genetic variation has been described worldwide, in the oxidative metabolizing enzymes of alcohol, particularly for the alcohol dehydrogenase (ADH2) and the aldehyde dehydrogenase (ALDH2) enzymes. High frequencies of the mutant class I ADH2 b subunit (ADH2*2) and low Km ALDH2 (ALDH2*2) alleles have been reported among orientals in the subtropical countries (Japan, Korea, and China). The high frequency of the inactive ALDH2*2 allele was also observed in Chinese sub-population (Thai-Chinese) of Southern Thais in our former study. In this report, we have further investigated the ADH2 genotypes among the three sub-populations of Southern Thais (101 Thai-Buddhists = TB, 103 Thai-Muslims = TM, and 67 genuinely Chineses, Thai-Chineses = TC) who have previously been ALDH2 genotyped. Using the method of amplified product length polymorphism (APLP) analysis, the difference between ADH2*1 and ADH2*2 alleles, by a single-base substitution of His (CAC) to Arg (CGC) at amino acid position 47 within the exon 3, were represented by a 57-bp and a 53-bp products, respectively. The patterns of ADH2 genotypes were visualized from the ethi-dium bromide-stained polyacrylamide gel electrophoresis. The frequency of ADH2*2 allele was significantly higher in TC (0.72) when compared with TB (0.40) and TM (0.48), [ c2 yate = 32.432, (p<0.001), and c2 yate = 18.7, (p<0.001), respectively]. However, the frequency of the ADH2*2 allele was not significantly different between the TB and TM sub-populations. This study has further supported our previous observation on the genetic differences among the sub-populations of the Southern Thais. Genetic differences related to alcohol metabolizing enzymes should be taken into consideration for future association and comparison studies in Southern Thai population.
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