Genetic polymorphisms of short tandem repeat loci D13S305, D13S631 and D13S634 in the Han population of Tianjin, China.

Short tandem repeat (STR) markers, also known as microsatellites, are extensively used in mapping studies, forensics and disease diagnosis due to their small dimension and low mutation and high polymorphism rates. In recent years quantitative fluorescence polymerase chain reaction (QF-PCR) has been successfully used to amplify STR markers in the prenatal diagnosis of common chromosomal abnormalities. This method provides a diagnosis of common aneuploidies 24-48 h after sampling with low error rates and cost; however, the size of different alleles, frequency, heterozygosity and distribution of STR markers vary among different populations. In the present study three STR markers, D13S305, D13S631 and D13S634, on chromosome 13 were analyzed in 350 unrelated individuals (200 males and 150 females) from the Han population of Tianjin, China using QF-PCR. Eleven, seven and 11 alleles of each marker were observed, respectively. The frequencies of the genotypes were in good agreement with Hardy-Weinberg equilibrium (P>0.05). The results showed that these three STR markers were highly polymorphic in the Han population of Tianjin, China. The study has provided basic data for use in the prenatal diagnosis of Patau syndrome.