DNA polymorphic patterns and haplotype arrangements of the apo A-1, apo C-III, apo A-IV gene cluster in different ethnic groups.

The allelic frequency of five different restriction fragment length polymorphisms (RFLPs) in the A-1, C-III, A-IV gene region has been determined in Caucasians, Negroes, Indian Asians, and Japanese. The polymorphic sites are with Taq-1 at the 5' end of the A-1 gene, with Msp-1 in the third intron of the A-1 gene, with Pst-1 in the intergenic sequence between the A-1 and C-III genes, with Sst-1 in the 3' non-coding region of the C-III gene, and with Pvu-II in the third intron of the C-III gene. The alleles identified by three of the RFLPs showed large differences in frequency amongst the races, especially between Caucasians and non-Caucasians. Alleles of the Msp-1 polymorphism and Sst-1 polymorphism, which were rare in Caucasians (frequencies 0.03 and 0.01), were more common in Japanese (frequencies 0.37 and 0.35), Indian Asians (frequencies 0.37 and 0.26), and Negroes (frequencies 0.31 and 0.31). In contrast with a Pvu-II polymorphism one allele was rare in Japanese and in Indian Asians (frequency 0.01) but more common in Caucasians (frequency 0.11). Linkage disequilibrium was evident between some of the alleles and a total of seven haplotypes were identified among the different races.