Performance Verification of SeqType® P52 Human Ancestry Identification SNP Detection Kit / 法医学杂志

Objective To evaluate the discrimination efficiency of the SeqType® P52 Human Ancestry Identification SNP Detection Kit based on a high-throughput sequencing platform in five Chinese ethnic groups. Methods Using the SeqType® P52 Human Ancestry Identification SNP Detection Kit based on a high-throughput sequencing platform, a total of 350 samples from Han, Tibetan, Mongolian, Uygur, and Yi populations in China were detected and population cluster analysis was performed. Results The effective sequencing depth of a single site in a single sample was ≥720×, and the average report rate was 96%. The mean values of allele frequency differences between the Tibetan, Mongolian, Uygur, Yi and Han population were 0.20, 0.05, 0.24 and 0.11, respectively. Using Structure 2.3.4 software under K=5 mode, independent ancestral component in Han, Tibetan and Uygur could be detected, which was consistent with the result observed from the principal component analysis （PCA）. For the Yi population, two thirds of them had relatively independent ancestral component close to the Tibetan population and one third were similar to the Uygur population. The Mongolian population had similar ancestral origin component with Han population. Conclusion The composite detection system with 52 screened ancestry-informative SNP sites has been established in this study, which can effectively analyze the composition and individual genetic components of populations from Han, Tibetan and Uygur. The ability to discriminate among Han, Mongolian and Yi needs to be further improved. The SeqType® P52 Human Ancestry Identification SNP Detection Kit can be used to infer the origin of an individual's ancestors in some forensic DNA cases.

Determination of Hair Shafts by InnoTyper? 21 Kit / 法医学杂志

Objective To explore the application value of InnoTyper? 21 kit in forensic practice. Methods Samples of hair shafts and saliva were collected from 8 unrelated individuals. Template DNA was ex-tracted by AutoMate ExpressTM forensic DNA automatic extraction system. DNA was amplified by Inno-Typer? 21 kit and AmpFeSTRTM IdentifilerTM Plus kit, respectively, and then the results were compared. Results After the amplification by InnoTyper ? 21 kit, complete specific genotyping could be detected from the saliva samples, and the peak value of genotyping profiles of hair shafts without sheath cells was 57-1219 RFU. Allelic gene deletion could be found sometimes. When amplified by AmpFeSTRTM IdentifilerTM Plus kit, complete specific genotyping could be detected from the saliva samples , and the specific fragment was not detected in hair shafts without sheath cells. Conclusion The InnoTyper? 21 kit has certain application value in the cases of hair shafts without sheath cells.

Modified TRIzol method for RNA and DNA co-extraction from blood / 法医学杂志

OBJECTIVE@#To establish a new method for RNA and DNA co-extraction from the same sample by TRIzol reagent.@*METHODS@#After the aqueous phase which contained total RNA was removed by traditional TRIzol method, the values of pH of the interphase phase and organic phase were adjusted. The DNA was precipitated with ethanol and purified with DNA IQ system. The purified DNA was measured in quality and quantity. As the template, it was amplified and typed by PCR-STR. The data was compared with that extracted by traditional TRIzol method.@*RESULTS@#The DNA extracted by this modified method showed a better result of quality and quantity than that by traditional TRIzol method and a good STR typing.@*CONCLUSION@#The modified TRIzol method is advisable and reliable to simultaneously extract both DNA and RNA from the same sample. It could be used for individual identification and paternity testing to satisfy the need of forensic science.

A new method of identifying the peripheral blood and the menstrual blood / 法医学杂志

OBJECTIVE@#To explore the tissue-specific gene expressions of the peripheral blood and the menstrual blood, and to search some specific factors to establish an effective method for identifying the peripheral blood and the menstrual blood.@*METHODS@#The specific products of the peripheral blood and the menstrual blood were detected by RT-PCR and separated by electrophoretic technology.@*RESULTS@#Beta-spectrin (SPTB) as one specific marker of peripheral blood and 18S rRNA as a kind of the housekeeping gene were expressed in both the peripheral blood and the menstrual blood. However, matrix metalloproteinase 7 (MMP7) as one specific marker of menstrual blood and human beta defensin 1 (HBD1) as one specific marker of vaginal discharge were only found in the menstrual blood.@*CONCLUSION@#There are differences of specific gene expressions between the peripheral blood and the menstrual blood. They could be accurately distinguished from each other by using the combination of fluorescence technology and RT-PCR to detect the specific identification of mRNA.