Characteristics of beta A chromosome haplotypes in Japanese.

DNA polymorphism patterns linked to the beta A-globin gene were analyzed in healthy Japanese using four different restriction endonucleases. The chromosomes with the beta A-globin gene were mapped through an evaluation of the presence of seven different restriction sites (HincII 5' to epsilon; HindIII in G gamma and A gamma; HincII in, and 3' to, psi beta 1; AvaII in beta; Bam-HI 3' to beta). Among 36 chromosomes analyzed, 20 chromosomes had a haplotype of [+-----+]. Among 55 individuals examined, 7 possessed a homozygous haplotype of [+-----+]. All Japanese with the A gamma T-globin gene had a subhaplotype of [-++-+] 5' to the delta-globin gene. Their major haplotypes were [-++-+-+] and [-++-++-]. It was expected that the presence of the A gamma T-globin gene in Japanese may be deduced from subhaplotypes 5' to the delta-globin gene.