Method for recognizing mixed semen stains from two individuals

Abstract

The invention belongs to the technical field of forensic medicine, and particularly relates to a method for recognizing mixed semen stains from two individuals. According to the method, the individuals are separated and recognized by ABH antigen corresponding to ABO blood types of the individuals on spermoblast surfaces. The method particularly includes the steps: 1 preparing the mixed semen stains of the two individuals with ABH antigenic diversity; 2 performing immunohistochemical staining by the aid of labeled A, B and H antibodies, and collecting spermoblast of different ABH blood types bya cell capture technology; 3 performing PCR (polymerase chain reaction) amplification and capillary electrophoresis to perform genetic typing on STR (short tandem repeat) loci. According to the method for recognizing the mixed semen stains from the two individuals, individual origins of DNA (deoxyribonucleic acid) in the mixed semen stains of a plurality of individuals can be effectively determined according to gene level, the step of identifying histologic origins of body fluids or spots on criminal investigation scenes is greatly simplified, and accurate scientific evidence can be providedfor defining case quality, determining criminal suspects, performing conviction and sentencing and the like.

Description

technical field [0001] The invention belongs to the technical field of forensic medicine, and in particular relates to a method for identifying mixed sperm spots from two individuals. Background technique [0002] The most common mixed samples are women’s vaginas or semen spots left on underwear and bed sheets in rape cases. After digesting the female components, a single male type can be obtained. But in some gang rape cases, the semen of multiple male individuals is often mixed together, and contains a large number of female epithelial cells. At present, 1) the simple Y chromosome identification method can be used in the existing technology, that is, due to the paternal inheritance of the Y chromosome, males belonging to the same paternal family have the same Y chromosome STR type. In this case, STR results can exclude unrelated individuals, but cannot serve the purpose of personal identification. 2) Differential lysis method, this method is better for mixed spots that a...

AI Technical Summary

Problems solved by technology

In this case, STR results can exclude unrelated individuals, but cannot serve the purpose of personal identification

2) Differential lysis method, this method is better for mixed spots that are not polluted and contain more sperm, but the extraction effect for difficult mixed spots that are seriously polluted on site is not ideal; The interference of inhibitors such as pigments and pigments will reduce the amplification efficiency or fail to amplify, so the typing effect is poor

3) Laser capture microdissection technology. This method needs to find intact sperm cells under a microscope and cut them for enrichment. Due to the limitation of the number of sperm obtained, sometimes it cannot meet the quantitative requirements of PCR detection sensitivity.

In addition, in some old or degraded samples, the tails of sperm cells are often broken and lost, and it is difficult to identify typical sperm cells under a microscope, making it difficult to operate

4) It is very difficult to separate and test male substances by using conventional analysis methods. Sometimes even if the typing results are obtained, it often shows that the typing of each mixed component coexists with each other, or the phenomenon that the female components are dominantly amplified, which makes the result difficult. analysis becomes complicated

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