Abstract: Objective To explore and analyze the mutations of 15 Short Tandem Repeat (STR) loci using IdentifilerTM system in paternity identification. Methods 2 712 cases of paternity testing were carried out using IdentifilerTM PCR Amplification Kit. Results Of the 2362 paternity testing cases, mutations of single locus were observed in 51 cases. The mutation loci included D8S1179, D21S11, D7S820, CSF1PO, D3S1358, D13S317, D16S539, D2S1338, D19S433, vWA, D18S51, D5S818 and FGA, with the D21S11 locus having a highest mutation rate (0.369%). Thirty-six of the STR mutations were from paternal source, 7 from maternal source, and the rest (9) were undeterminable. The mutation rates at D21S11 were highest (0.369%). Conclusion Mutations of STR loci are relatively common in human genome. Therefore, re-testing of additional relatively stable STR loci with lower mutation rates is necessary when one or two loci exclusions are encountered in paternity testing.

Key words: identifilerTM system, locus, mutation, short tandem repeat (STR)