ABSTRACT
[Objective] To explore how to deal with the paternity test of complex adoption cases. [Method] Samples from 13 families, in which adoptive parents were suspected related to biological parents, were genotyped using "Identifder + Sinofder + Powerplex 16" combined system (D8S1179, D21S11, D7S820, CSFIPO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, VWA, TPOX, D18S51, D5S818, FGA, D6S1043, D12S391, PentaD, PentaE) followed by further statistical analysis. [Result] Among all 13 cases, 2 were completely accordance with the Mendel law, PI > 10 000. There found more than 3 inconsistent loci in 8 cases. And found 1～2 inconsistent loci in 3 cases, needed to test more STR loci until PI≥10 000. The half sibling index (HSI) was also calculated with ITO method. The adoptive parents of 2 cases were not excluded from a full sibling with biological parents. In addition, Y-STR loci were tested for 4 cases (father/son). Two adoptive fathers of them were not excluded from the paternal relationship with biological fathers. [Conclusion] The most (76.9%) of all (13) complex adoptive cases of paternity test could be drawn a definite conclusion with combined system of "Identifder + Sinefiler + Powerplexl6". Minority (23.1%) of them was not definite yet and needed testing more STIR loci. Meanwhile, we suggested adding Y-STR tests and providing HSI for reference.
ABSTRACT
[Objective] To propose a criterion for making conclusions on paternity tests based on STR genotyping. [Method] To use binomial distribution formula to calculate minimal numbers of STR loci that must be tested for different scenarios in paternity testing. [ Results ] We proposed a set of criteria for making STR paternity testing conclusions. For triplet tests, concluded "paternity positive" for the following four cases when the cumulative paternity index (PI) was greater than 10 000: 1) no inconsistent STR locus was detected in 15 loci (PE > 0.571 4/locus) or 2) only one inconsistent STR locus was detected in 19 loci or 3) only two inconsistent STR loci were detected in 28 loci or 4) only three inconsistent STR loci were detected in 35 loci; otherwise, concluded "paternity negative" when at least four inconsistent STR loci had been detected. For single parent tests, concluded "paternity non-exclusive" for the following cases when the cumulative PI was greater than 10 000: 1) no inconsistent STR locus was detected in 18 loci (PE>0.411/locus) or 2) only one inconsistent STR locus was detected in 29 loci or 3) two inconsistent STR loci were detected in 41 loci; concluded "paternity negative" when three or more inconsistent loci were detected. [Conclusion] Our experience has proven that these criteria are robust in STR paternity testing.