Research Progress on the Detection Method of DNA Methylation and Its Applica-tion in Forensic Science / 法医学杂志

A s an im portant part of epigenetic m arker, D N A m ethylation involves in the gene regulation and attracts a w ide spread attention in biological auxology, geratology and oncology fields. In forensic science, because of the relative stable, heritable, abundant, and age-related characteristics, D N A m ethyla-tion is considered to be a useful com plem ent to the classic genetic m arkers for age-prediction, tissue-identification, and m onozygotic tw ins' discrim ination. V arious m ethods for D N A m ethylation detection have been validated based on m ethylation sensitive restriction endonuclease, bisulfite m odification and m ethylation-C pG binding protein. In recent years, it is reported that the third generation sequencing m ethod can be used to detect D N A m ethylation. T his paper aim s to m ake a review on the detection m ethod of D N A m ethylation and its applications in forensic science.

Study on the preparation method of capillary electrophoresis sieving medium based on domestic genetic analyzer / 中国法医学杂志

Objective To prepare a capillary electrophoresis sieving medium and apply it in GA118-16A genetic analyzer. Methods The white solid polyacrylamide (LPA) was prepared by polymerization and lyophilized. Through the swelling of the sol buffer, the sieving medium was obtained. The sieving medium was evaluated by 1) characterizing the parameters, including molecular weight, structure and viscosity, 2) applying in the GA118-16A genetic analyzer, including the spatial calibration, the spectral calibration and the STR analysis.. Results The prepared sieving medium Mw 1.8 x 105Da, Mn 1.2 x 105 Da, is of correct structure and high purity. The polydispersity was 1.5The spatial calibration and spectral calibration files can be established successfully in GA118-16A genetic analyzer, and the sieving medium can effectively separate the DNA fragments with 1bp difference. The STR profile is of sharp peaks, no impurity peaks, no tail, and no peak loss. Conclusion The sieving medium prepared by the method can be applied to domestic genetic analyzer such as GA118-16A.

AS-PCR Assay for 20 mtDNA SNP Typing and Haplotype Frequency / 法医学杂志

Objective To develop a multiplex allele-specific PCR (AS-PCR) assay with three-color fluo-rescence labeling for mitochondrial DNA (mtDNA) SNP typing. Methods Based on the principle of AS-PCR, the primer sets were designed for 20 SNP located on the coding region of mtDNA and divided in-to 2 groups labeled with FAM and HEX fluorescence, respectively. A primer set included two forward (reverse) allelic specific primers with different sizes and a generic reverse (forward) primer. Blood sam-ples from 200 unrelated individuals were analyzed by AS-PCR and capillary electrophoresis. Three ran-dom samples at least for each SNP site were examined and verified by direct sequencing. The haplotype frequency was investigated. Results Distinct electropherograms of 200 blood samples were obtained suc-cessfully. The typing results of direct sequencing were identical to those obtained from AS-PCR. The minimum detectable DNA concentration was 0.2 pg under the system of 10μL. The sensitivity of the DNA concentrations ranged from 0.5 to 5 pg. The 200 individuals were assigned into 15 haplotype, and the haplotype diversity was 0.906 0. Conclusion AS-PCR is a simple, rapid and efficient method for mtDNA SNP typing, and can be applied to forensic practice.