THE CODON-31 POLYMORPHISM OF THE P53-INDUCIBLE GENE P21 SHOWS DISTINCT DIFFERENCES BETWEEN MAJOR ETHNIC-GROUPS

The codon 31 polymorphism of the p53-inducible protein p21 was studied with respect to allele frequency variations between some major ethnic groups, The frequency of the A1 (Arg) allele showed highly significan t variations ranging from 4% in Caucasians (Swedes) to 50% in Chinese. Compared to Caucasians, a relatively high frequency was found in Afri can Blacks (29%) and Indians (16%). Furthermore, Finns and Mordvinians also had higher frequencies (9-10%) than west Europeans (French and S wedes), consistent with an Asiatic Mongoloid influence known to exist in Finno-Ugrian tribes. The geographic allele frequency patterns of p5 3 and its effector protein p21 were quite different. The p21 A1 mutati ons in African, Asiatic and European populations were identical at the DNA level, The geographical distribution of the A1 allele suggests an independent origin in Africa and Asia, The very pronounced ethnic dif ferentiation of tumour suppressor genes and the fact that tumour suppr essor genes may be teratogenes suggest that these polymorphisms are ma intained by natural selection, probably operating in the intrauterine period.