Objective: To detect polymorphic points of the 7th intron of human p53 oncogene.
Methods: Polymerase chain reaction (PCR) and double- strand DNA direct sequencing were used to analyse sequence alteration of p53 intron 7. One hundred and five cases of normal human peripheral blood samples with no genetic relation were investigated.
Results: There were two polymorphic points in the 7th intron of p53 gene. The first one was localized at 73 base pair (bp) to 3'-end of exon 7; the other one at 93. Three genotypes were found. Twenty-two cases were of type TG, 37 cases were of type CT, and the other 46 cases were of heterozygote. Because the first point was alteration of GGGCCC to GGGTCC or its heterozygote, it had a point alteration of enzyme Apa I.
Conclusion: There are two polymorphic points in the 7th intron of human p53 gene, which may be of importance to identification of individual genetic relation and to judging of a case in forensic medicine.