[High polymorphism at the human P gene locus in Chinese Han and Tibetan populations]

The authors studied two synonymous sites polymorphism (A355A, G780G) and one intervening sequence polymorphism(IVS13-15) of human P gene in 181 and 171 individuals sampled from Chinese Han and Tibetan populations respectively.

Genomic DNA was extracted from the ACD-blood specimens collected from 352 healthy unrelated individuals by phenol-chloro methods. The amplification of three fragments was performed using PCR technique; the product was digested with restricted enzyme. Agarose electrophoresis was used for typing the PCR product.

There were two alleles at each exon variety locus; the allele frequencies in both A355A and G780G were of significant differences between the two populations ( chi(2)=24.54,chi(2)=37.05,P>0.001). No significant difference was found in allele frequency in IVS13-15 locus between the two populations (chi(2)=2.06,P>0.05). And in each of the populations, no significant difference was noted in the genotype frequency between the male and the female. The test for Hardy-Weinberg equilibrium showed that the genotype distributions observed in the two populations were correspondent with the expected.

There is a remarkable difference in the distribution of allele frequencies at P gene locus between Chinese Han and Tibetan populations, which is related to the variation in skin pigmentation of these two Chinese population.