Time filter

Source Type

Li Z.H.,Sichuan University | Yan J.,Sichuan University | Tang D.Z.,CHN National Accreditation Service for Conformity Assessment | Zhu H.,Sichuan University | And 3 more authors.
Forensic Science International: Genetics Supplement Series | Year: 2013

Tri-allelic SNP has been regarded as a potential marker in forensic utility. Compared with the conventional binary SNP marker, it has showed obvious advantage in the analysis of mixed and degraded DNA samples. Previously, we constructed a multiplex system with 20 tri-allelic SNP loci by the pyrosequencing (PSQ) method and SNaPshot technique. In the present work, validation studies were carried out to determine the efficacy and reliability of the multiplex assay for forensic identification. Species specificity, sensitivity, artificially degraded samples and mixture study were executed in our research, according to the FBI/National Standards and Scientific Working Group on DNA Analysis Methods (SWGDAM) guideline. The results demonstrated that the multiplex system was sensitive to 1. ng of input DNA. The complete SNP profiles could be consistently detected from the degraded DNA. No profiles were obtained in the forensically relevant animals. Additionally, using the multiplex SNP system, the presence of a mixture of two DNA samples in a ratio up to 3:7 could be recognized reliably. In conclusion, the 20-tri-allelic SNP multiplex system was suitable for paternity testing and human identification in forensic science. © 2013 Elsevier Ireland Ltd.


Zhou D.,Sichuan University | Yan J.,Sichuan University | Tang D.Z.,CHN National Accreditation Service for Conformity Assessment | Liao L.C.,Sichuan University | And 3 more authors.
Forensic Science International: Genetics Supplement Series | Year: 2013

The single nucleotide polymorphisms on the Y chromosome (Y-SNPs) have been considered to be particularly valuable in forensic casework. However, Y-SNPs were mostly population specific and lacked biallelic polymorphisms in the Asian population. We previously established a novel Y-SNPs multiplex system for the Chinese Han population using Pyrosequencing technology and SNaPshot method. The system consisted of 20 Y-SNPs markers that were highly polymorphic and of value to establish haplotypes in the Chinese Han population. In the present study, validation of the multiplex system, including sensitivity, degraded DNA, species specificity and mixture study, were performed according to the FBI/SWGDAM guideline. Our results demonstrated the minimal amount of DNA input with which a complete SNP profile could be detected was 300. pg. Using the multiplex system, the reliable result of Y-SNPs typing could be obtained even from degraded DNA. No corresponding SNP profiles were observed in the forensically relevant animal species. Additionally, the male-female mixture study showed that female DNA did not influence the results of Y-SNPs typing even in the background of more than 500-fold excess of female DNA. In conclusion, the novel Y-SNPs multiplex system could be used as a powerful tool for forensic applications in the Chinese Han population. © 2013 Elsevier Ireland Ltd.

Loading CHN National Accreditation Service for Conformity Assessment collaborators
Loading CHN National Accreditation Service for Conformity Assessment collaborators