[Microsatellite polymorphisms at the TNF locus in Hubei Han population].

OBJECTIVE: To investigate the distribution of tumor necrosis factor(TNF) microsatellite polymorphisms in Chinese. METHODS: DNA was extracted from 164 unrelated healthy individuals' EDTA-blood. TNF microsatellite alleles were typed using PCR technique followed by high voltage denaturing PAGE with silver staining at the same time the PCR products were cloned and sequenced. RESULTS: Thirteen alleles and forty kinds of genotypes were detected at the TNFa locus; two alleles and three kinds of genotypes at the TNFa locus. The polymorphism information contents (PIC) were 0.80 and 0.28 respectively no deviation from Hardy-Weinberg equilibrium was observed. Statistical analysis showed that the distribution of TNFa allele frequencies in Chinese Han population was significantly different from that in European Caucasian or in Japanese P<0.01. The result of sequencing revealed that the copy number of dinucleiotide repeats within the same TNF allele was not consistent with that in the reports from western countries. CONCLUSION: There exists ethnic difference in the distribution of TNFa allele. Further investigations will be necessary to define more accurately and clearly the TNFa alleles.