Abstract: Using multiplex amplification and five fluorescent techniques ( 6FAM, VIC, NED, PET and LIZ) , polymorphism distributions of 15 STR loci ( D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, VWA, TPOX, D18S51, D5S818 and FGA) were investigated in the Naqu Tibetan population. Gene frequency, power of discrimination (DP) , heterozygosity ( H) , polymorphism information content ( PIC ) and probability of paternity exclusion ( EPP) were determined. In addition, HardyWeinberg equilibrium of the frequencies were also tested for all loci. Our results indicate the following:
1) Allele frequencies in the 15 STR loci meet the HardyWeinberg equilibrium.
2) The power of discrimination of the 15 STR loci is 0.7588-0.9604, heterozygosity of the 15 STR loci is 0.4762-0
8620, the polymorphism information content of the 15 STR loci is 0.4464-0.8615, and the probability of paternity exclusion of the 15 STR loci is 0.3850-0.8560.
3) The cumulative power of discrimination of the 15 STR is 0.999999 999 and the cumulative probability of paternity exclusion is 0.999999 998. On the basis of these results, the 15 STR loci could be used as the genetic markers for the Naqu Tibetan population in studies of anthropology, linkage analysis of genetic disease, individual identification and paternity test in forensic medicine.

Key words: Short tandem repeat (STR); Polymorphism; Tibetan