p53 Polymorphisms and Haplotypes Show Distinct Differences between Major Ethnic Groups

Abstract

Three different p53 DNA polymorphisms (a 16-bp duplication in intron 3 and BstUland MsplRFLPs in exon 4 and intron 6, respectively) and haplotype combinations were studied in some major ethnic groups: Caucasians (Swedes), Chinese, Dravidian Indians and African Blacks. Significant ethnic differences in single polymorphisms were found between all groups except for African Blacks-Dravidian Indians, who differed only in their MspI7-16-bp duplication haplotype distribution. Since previous results have shown that p53 alleles are correlated with latitude (degree of insolation), the similarity between these two groups, who are genetically quite distinct, may be due to ecological adaptation to similar climatic conditions. All other major ethnic groups differed significantly from each other with respect to their haplotype distributions; thus, p53 alleles and haplotypes should be very useful as anthropological markers. Asiatic Mongoloid groups appear to be characterized by very low frequencies of the 16-bp duplication and the MspIA1 allele. These mutations have probably been introduced by migration to east Asia from either Europe or Africa, where the highest frequencies were found. The results of this study indicate that p53, besides its role as a tumor suppressor, shows distinct ethnic heterogeneity and may be involved in ecological (climatic) adaptation.

Risk assessment of p53 genotypes and haplotypes in tobacco‐associated leukoplakia and oral cancer patients from eastern india

“…The haplotypes constructed have been expressed in the order intron 3-codon 72-intron 6. 24 In our study, 6 of 8 possible haplotypes were observed in all groups. The haplotype frequencies were significantly different between leukoplakia and controls (p 5 0.008; Table VI).…”

“…28,32,34,43 Similar analysis with third generation Dravidian Indians from Singapore reported the codon 72 allele 1 frequency as 0.54. 24 In this study, allele 1 frequency in controls was found to be 0.52. The frequency of allele 1 (intron 6 uncut variant) at the NciI locus (nt 13494) has been reported as 0.02 in the Chinese, 0.19 in south Indians and African blacks, 0.22 in Hispanic population and 0.33 in African Americans.…”

“…24 The allele 1 (Proline) frequency at codon 72 in different world populations are as follows: 0.17 in Swedish Saamis, 0.24 in Finns, 0.29 in Sweeds, 0.38 in Chinese from Singapore, 0.47 in Chinese from Guizhou and 0.63 in African Blacks (Nigerians). 24,42 Another study with the Caucasians, Hispanics and African Americans reported the frequency of allele 1 at codon 72 as 0.21, 0.49 and 0.63, respectively. 25 The allele 1 frequency in Indian population from different geographic regions were reported to vary from 0.45-0.56.…”

“…The frequency of allele 1 (intron 6 uncut variant) at the NciI locus (nt 13494) has been reported as 0.02 in the Chinese, 0.19 in south Indians and African blacks, 0.22 in Hispanic population and 0.33 in African Americans. 24,25 At the intron 3 locus, allele 2 (presence of 16 bp duplication) frequencies were reported to be 0.05 in Chinese, 0.23 in south Indians, 0.25 in African blacks, 0.24 in Hispanics and 0.32 in African Americans. 24,25 In this study, the frequencies of allele 2 at intron 3 and allele 1 at intron 6 in controls were 0.19 and 0.22, respectively.…”

“…22 The absence of the duplication at intron 3, Pro at codon 72 and absence of NciI restriction site at intron 6 is defined as allele 1 at each of the 3 loci, respectively. 24,25 We have adopted a similar allelic nomenclature in this article.…”