A novel 6-dye STR 25-plex DNA typing system for forensic casework and databases / 中国法医学杂志

To develop and validate a novel 6-dye STR(short tandem repeat) 25-plex DNA typing system for forensic DNA profiling and databases. In this study, a novel STR 25-plex DNA typing system that includes 24 autosomal STRs (D1S1656, D2S1338, D2S441, D3S1358, D5S818, D6S1043, D7S820, D8S1179, D10S1248, D12S391, D13S317, D16S539, D18S51, D19S433, D21S11, D22S1045, CSF1PO, FGA, Penta D, Penta E, TH01, TPOX, vWA, D11S4463) and Amelogenin was developed. Validation studies demonstrated the sensitivity, accuracy, and reproducibility of our novel STR 25-plex DNA typing system. The sensitivity of the STR 25-plex DNA typing system was demonstrated by the ability to obtain complete profiles from as little as 0.125ng of human DNA. Specificity testing was demonstrated by the lack of cross-reactivity to a variety of commonly encountered animal species and microbial pool. For stability testing, full profiles were obtained with humic acid concentration ≤60ng/μL and hematin ≤600μM. For forensic evaluation, the selected 24 autosomal STRs followed the Hardy–Weinberg equilibrium. Since 24 autosomal STRs were independent from one another, PM (Probability matching) was 3.5434×10-28, TDP (Total Probability of Discrimination Power) was 0.999999999999999999999999969863, and CEP (Cumulative probability of exclusion) was 0.99999999375. The new STR 25-plex typing system is sensitive, reproducible, and stable, therefore it is highly applicable for use in national DNA database and can help to facilitate international data sharing.

Optimization of a forensic DNA extraction kits and its applicability evaluation / 中国法医学杂志

Objective To construct a rapid genetic DNA extraction method, with nano magnetic beads, self-designed reagents system and extracting process. Method Part I: DNA extraction from old blood cotton swab sample with self-designed DNA extraction kit, then quantiifed by UV spectrophotometer. The method was further optimized on the preliminary results. Part II: All kinds of difficult DNA sample were tested with optimized kit, to detect the applicability of the kit. Result By improving the experimental condition, the extraction effects of different DNA sample is good, meanwhile, the extraction cost is relatively low.