Abstract: Objective To investigate the application of dinucleotide STR locus in paternity testing. Methods Dinucleotide STR locus D6S261 was selected and the paternity testing blood samples were amplified using 200 random blood samples, 16 family samples and 193 paternity test samples. Data of the PCR products were collected by 3130XL Genetic Analyzer and the genetic parameters of population were calculated by PowerStats v12. Results Fifteen alleles and 50 genotypes were found and H, DP, PE and PIC were 0.850, 0.953, 0.695, and 0.820, respectively. The typing results of both family samples and paternity test samples were accord with the law of inheritance, which no mutation was discovered. Conclusion The genetic polymorphisms of D6S261 show good characteristics with low mutation rate and high stability. It can be an effective method to solve the indetermination caused by mutation in paternity testing if the stutter bands can be decreased.

Key words: forensic genetics, polymorphism, genetic, dinucleotide, paternity testing