IS P53 POLYMORPHISM MAINTAINED BY NATURAL-SELECTION

We present here a new interesting feature of the human tumor suppresso r gene p53: a very pronounced ethnic and clinal variation of polymorph ic codon 72 alleles. The frequency of the A1 (Pro) allele showed a nor th-south dine from 17% in Swedish Saamis to 63% in African Blacks (Nig erians), and there was a significant (p < 0.001) correlation (r = 0.95 ) between the A2 frequency and latitude. In the Finnish and Swedish po pulations no significant differences were found with respect to the ge notype and allele distributions in spontaneously aborted fetuses and l iveborn children, which makes differential intrauterine selection unli kely. However, the ethnic and clinal variations suggest that the codon 72 polymorphism is balanced and maintained by natural selection.