Method and kit for extracting sperm cell DNA from sexual assault case check sample by differential splitting decomposition

Abstract

The invention discloses a method and kit for extracting sperm cell DNA from a sexual assault case check sample by differential splitting decomposition. The kit comprises a box body, a DNA extraction bin and a DNA amplification bin are arranged in the box body, and a sexual assault check sample splitting decomposition tube for extracting target DNA, a first storage tube for storing a mild splittingdecomposition solution and a second storage tube for storing protease K, a third storage tube used for a sperm cell splitting decomposition and a fourth storage tube for storing reducing agent are placed in the DNA extraction bin. According to the method and kit for extracting sperm cell DNA from the sexual assault case check sample by differential splitting decomposition, the reagents needed forDNA splitting decomposition extraction and amplification are packed in the kit, the DNA extraction and amplification is convenient, a legal medical expert can conveniently indentify the DNA, and theidentification efficiency is improved; and a mild splitting decomposition environment is provided for the extraction of sperm cell DNA, the residual epithelial cell DNA in the sperm cell precipitationsolution is effectively removed, the pure sperm cell DNA is obtained, and the identification accuracy is improved.

Description

technical field [0001] The invention relates to a method and kit for differentially cracking and extracting sperm cell DNA in test materials of sexual assault cases, belonging to the technical field of forensic DNA identification. Background technique [0002] In sexual assault cases, the sperm collected from the victim's vagina can usually be used as direct evidence of the criminal suspect's violence, but when the sperm is collected from the victim's vagina with swabs and other sampling tools, epithelial cells exfoliated from the vaginal wall will also be collected at the same time Therefore, before performing DNA fingerprinting on samples, it is necessary to remove DNA from female vaginal epithelial cells, and use purified sperm cell-derived DNA for DNA fingerprinting analysis. [0003] The general steps of routine sample processing for sexual assault case materials are as follows: first step, sample collection; second step, provide a mild lysing environment to produce a m...

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Problems solved by technology

[0003] The general steps of routine sample processing for sexual assault case materials are as follows: first step, sample collection; second step, provide a mild lysing environment to produce a mixture of epithelial cell DNA and unlysed sperm; third step, centrifugation Form the sperm cell precipitate and the supernatant solution containing epithelial cell DNA, and discard the supernatant solution; the fourth step is to repeatedly rinse the precipitate to remove residual epithelial cell DNA; the fifth step is to violently lyse the environment to obtain purified sperm DNA; The defect of the above process is that the epithelial cell DNA remains in the solution in the gap between the sperm cell sedimentation, which is difficult to remove.

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