P53 POLYMORPHISMS AND HAPLOTYPES IN DIFFERENT ETHNIC-GROUPS

Three different p53 polymorphisms (a codon 72 BstUI RFLP, a 16-bp dupl ication in intron 3 and an MspI RFLP in intron 6) and haplotype combin ations were studied in three northern European populations, viz. Finns , Swedes and Swedish Saamis. Significant ethnic differences were found in the codon 72 and 16-bp polymorphisms. The three polymorphisms were in strong linkage disequilibria, all of which were highly significant (p < 1 x 10(-18)), and ethnic differences with respect to linkage dis equilibria were observed. Estimates of the frequencies of extended hap lotypes showed that the most common ('wild-type') haplotype in the thr ee populations was 2-1-2, viz, the codon 72 Arg allele linked to absen ce of the 16-bp duplication and presence of the MspI site. There were two additional common haplotypes, 1-1-2 and 1-2-1, and five rare haplo types with a combined frequency of about 0.03. The present results ind icate that extended haplotypes would be more informative in studies of population differences and associations between p53 germline mutation s and cancer.