ABSTRACT
Objective To investigate the genetic polymorphism of 90 autosomal SNPs in Guangdong Han population and assess their value in forensic medicine based on next generation sequencing. Methods Blood samples were collected from 100 unrelated individuals. Through using AutoMate ExpressTM Nucleic Acid Extraction System, DNA was extracted. HID-Ion AmpliSeq? Identity Panel was applied for library preparation while Ion OneTouch? 2 system (OT2) was employed for emulsion PCR (emPCR). NGS was performed on the Ion PGM? system. Sequencing results were analysed using the Torrent Suite v4.4.2 with the HID_SNP_Genotyper v4.3.1 plugin. The forensic parameters were calculated and compared with GoldeneyeTM 20A systems. Results According to the Bonferroni correction, the genotypes of 90 autosomal SNPs were in accordance with Hardy-Weinberg equilibrium and no linkage disequilibrium was observed. The average Ho of 90 autosomal SNPs was 0.423, the average DP was 0.560 and the average PIC was 0.329. The CDP (cumulative power of discrimination) of 90 autosomal SNPs system was 1-1.20×10-33, which was greater than that of 20A System. The CPEtri (cumulative excluding probability of trio paternity) was 0.999 999 911 and the CPEduo (cumulative excluding probability of duo paternity) was 0.999 882. Both of these two parameters were below that of 20A System. Conclusion It suggested that the 90 autosomal SNPs System can be applied to forensic individual discrimination and trio paternity testing independently. Besides, it is supposed to be used in the duo paternity testing as an assistant measure.
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.
ABSTRACT
Collaborative work using same samples for the parentage testing, which was intended to see the status and the quality of several DNA typing laboratories in Korea, was described. Samples were consisted of two sets, one was a trio case and the other was a deficient case with two children. Samples were sent to six laboratories, among which five submitted the result. Each laboratory had used different number and set of STR loci using 14 - 23 loci, and total 33 different loci were used. Only one VNTR locus, D1S80 was included and all the remaining were STR loci. The loci included in the commercial kits were used more frequently. One laboratory had used Korean-made commercial kits. All the laboratories gave the same results about the parentage, although results for one locus were not the same through different laboratories. There existed minor difference in the PI calculation, especially in the statistical parameters such as allelic frequences, which might gave confusion to users of the results who were not familiar with the test. Necessity about the standardization and profiling data were discussed.