APPARENT MONOMORPHISM OF ALDH2 IN 7 AMERICAN-INDIAN POPULATIONS

Deficiency of mitochondrial aldehyde dehydrogenase (ALDH2) has been pr eviously reported in South American Indians. We therefore assayed five individuals from each of five South American Indian populations (Quec hua, Karitiana, Ticuna, Surui, Guahiba), and two North American popula tions (Maya and Moskoke) for the presence of the Oriental ALDH(2)(2) v ariant. These samples were also surveyed for other alleles altering AL DH2 function. Allele-specific amplification assay (ASA) did not detect the ALDH(2)(2) allele in any of the New World populations studied. Th e entire coding sequence of the ALDH2 cDNA was enzymatically amplified in partially overlapping fragments. Each fragment was digested using restriction endonucleases and subfragments 148-285 b.p. in length were analyzed by the single-stranded conformation polymorphism (SSCP) tech nique. No variants were detected within the coding region of the ALDH2 gene in any of the seven American Indian populations. Three potential ly correct explanations for these results are suggested. First, an ALD H2 polymorphism is present but undetectable by SSCP; second, none of t he studied individuals were ALDH2 negative; third, the polymorphism oc curs beyond the coding region of ALDH2 gene.