ABSTRACT
Objective To discuss the risk in duo paternity testing. Methods 22 fictitious duo families formed by 22 pairs of unrelated individuals having one or zero inconsistent locus were selected after detected by GoldeneyeTM 20A Kit. The 22 fictitious duo families were further tested with STRtyper-10G kit and/or AGCU 21+1 STR kit until there were more than 3 inconsistent loci and the cumulative paternity index(CPI) value was less than 0.0001. According to the three excluding rules, ① number of inconsistent loci>3; ② CPI ≤ 0.0001; ③ accord with both ① and ② , using multiple STR systems, such as 19 STR loci, 26 STR loci, 39 STR loci and 46 STR loci to test and discuss whether there is difference among the excluding result of unrelated individual. Results Among those 22 fictitious duo families, using three excluding rules, None was excluded by 19 STR loci, and all was excluded by 39 STR loci. Conclusion Duo paternity tests may get a wrong result using only 19 loci system. To reduce the error risk 39 STR-loci systems would be suggested.