Development And Application Of RNA In Forensic Genetics

ObjectivesEstablish a fast, accurate and sensitive method of body fluid identification，which shouldbe compatible with the classification of present DNA so as to identify simultaneously the sourceof the tissues and the recognition of the individuals by body fluids extracted on the scene of thecrime. In this paper, we tried to screen specific mRNA logo from the body fluids such as theperipheral blood, the menstrual blood, the semen, the vaginal secretion and the saliva based onthe tissue-specific gene expression. RNA and DNA were judged by the source of body fluids andthe recognition of the individuals respectively.MethodSamples of the peripheral blood, the menstrual blood, the semen, the vaginal secretion andthe saliva were collected separately as required by the experiment. The methods of extractingRNA and DNA simultaneously were compared and established. 7 pairs of primers were selectedfrom the source of body fluid tissues and different fluorescent markers were used. The length ofamplification products in each period（section）was limited below 300bp.The same standard was adopted for all the amplifications so that the 7 pairs of primers were to beamplified under the same parameters. RNA retrovirus amplification products and DNAamplification products were inspected by the electrophoresis of capillary gel. The peripheralblood, the menstrual blood, the semen, the vaginal secretion and the saliva were verifiedseparately by the method established.Results1 RNA and DNA were extracted simultaneously by TRIzol .2 Multiple pairs of primers were screened by their sequences of target samples; the systemof optimized amplification products was explored and the conditions of amplification productsatisfied the requirements of all the pairs of primers.3 The peripheral blood, the menstrual blood, the semen, the vaginal secretion and the salivawere verified and reliable results have been secured.4 The above 5 fluids from different body parts could express the house-keeping gene18S,GAPDH; in addition, the peripheral blood expressed SPTB; the menstrual blood expressedMMP-7, SPTB, HBD-1; the semen expressed PRM-2; the vaginal secretion expressed HBD-1;and the saliva expressed STATH. Conclusion1 This paper establishes an effective and practical method to identify the body fluids, andthe method has been verified in practical cases.2 A method of verifying the source of body fluid tissues is Established by examining thelevel of RNA expression, for different types and functions of cells and tissues are expresseddifferently in the models of RNA expression. RNA is extracted while the individual identificationis inspected by DNA.3 RNA as the logo of the research target in the identification of body fluid has providedfurther insight in the research.