P53 POLYMORPHISMS AND HAPLOTYPES SHOW DISTINCT DIFFERENCES BETWEEN MAJOR ETHNIC-GROUPS

Three different p53 DNA polymorphisms (a 16-bp duplication in intron 3 and BstUI and MspI RFLPs in exon 4 and intron 6, respectively) and ha plotype combinations were studied in some major ethnic groups: Caucasi ans (Swedes), Chinese, Dravidian Indians and African Blacks. Significa nt ethnic differences in single polymorphisms were found between all g roups except for African Blacks-Dravidian Indians, who differed only i n their MspI7-16-bp duplication haplotype distribution. Since previous results have shown that p53 alleles are correlated with latitude (deg ree of insolation), the similarity between these two groups, who are g enetically quite distinct, may be due to ecological adaptation to simi lar climatic conditions. All other major ethnic groups differed signif icantly from each other with respect to their haplotype distributions; thus, p53 alleles and haplotypes should be very useful as anthropolog ical markers. Asiatic Mongoloid groups appear to be characterized by v ery low frequencies of the 16-bp duplication and the MspI Al allele. T hese mutations have probably been introduced by migration to east Asia from either Europe or Africa, where the highest frequencies were foun d. The results of this study indicate that p53, besides its role as a tumor suppressor, shows distinct ethnic heterogeneity and may be invol ved in ecological (climatic) adaptation.