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.

Consistency study of PowerPlex 21 kit and Goldeneye 20A kit and forensic application / 法医学杂志

UNLABELLED@#To ensure the consistency of genotype results for PowerPlex 21 kit and Goldeneye 20A kit.@*METHODS@#The STR loci were amplified in DNA samples from 205 unrelated individuals in Beijing Han population. And consistency of 19 overlap STR loci typing were observed. The genetic polymorphism of D1S1656 locus was obtained.@*RESULTS@#All 19 overlap loci typing showed consistent. The proportion of peak height of heterozygous loci in two kits showed no statistical difference (P > 0.05). The observed heterozygosis of D1S1656 was 0.878. The discrimination power was 0.949. The excluding probability of paternity of triplet was 0.751. The excluding probability of paternity of diploid was 0.506. The polymorphism information content was 0.810.@*CONCLUSION@#PowerPlex 21 kit and Goldeneye 20A kit present a good consistency. The primer design is reasonable. The polymorphism of D1S1656 is good. The two kits can be used for human genetic analysis, paternity test, and individual identification in forensic practice.

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.

Genetic polymorphisms of 16 non-CODIS STR loci in Beijing Han population / 法医学杂志

OBJECTIVE@#To investigate the genetic polymorphisms of 16 non-CODIS loci (D6S477, D22-GATA198B05, D15S659, D8S1132, D3S3045, D17S1290, D14S608, D2S441, D18S535, D13S325, D10S1435, DlS2368, DIS1656, D7S3048, D10S1248 and D19S253) in Beijing Han population.@*METHODS@#The DNA of 300 unrelated individuals in Beijing Han population were PCR amplified using GoldeneyeM DNA identification system 18NC kit, and the PCR products were analyzed by electrophoresis through 3130XL genetic analyzer. The fragment sizes of alleles were taken subsequently by GeneMapper v3.2.@*RESULTS@#The distributions of genotype frequencies of 16 non-CODIS STR loci in Beijing Han population satisfied the Hardy-Weinberg equilibration. The population genetic parameters were obtained as followings: heterozygosity was 0.677-0.873; discrimination power, 0.890-0.967; probability of paternity exclusion, 0.393-0.741; and polymorphism information content, 0.706-0.853.@*CONCLUSION@#These 16 non-CODIS STR loci show great genetic polymorphisms in Beijing Han population, and are useful for the research of population genetics and forensic application.

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.

Isolating sperm cells by laser capture microdissection technique from mixture sample / 法医学杂志

OBJECTIVE@#To assess the application value of laser capture microdissection (LCM) technique for isolating a small number of sperm cells from mixture sample.@*METHODS@#Mixture samples were prepared with sperm cells and vaginal epithelia at different concentrations. Both LCM technique and the differential lysis method were employed to obtain sperm cells from the mixture samples, and DNA was extracted by magnetic beads method. STR genotyping was determined using Identifiler kit.@*RESULTS@#The successful STR genotype rate of sperm cells isolated from mixture samples with LCM technique was 92.86% (13/14). The rate of differential lysis method was 7.14% (1/14). The successful rates between the two methods were statistically different (P < 0.05).@*CONCLUSION@#LCM technique can effectively exclude the interference of female cell component and isolate a small number of sperm cells to obtain a single male STR genotyping. LCM technique is obviously better than the differential lysis method.