Isolation and Quantification of DNA from different evidences and role of RFLP in DNA fingerprinting

Author Name(s): Ninad Laxman Harkulkar*
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Over the past twenty years, DNA analysis has been revolutionalized forensic science and has become a dominant tool in law enforcement. The DNA is unique for each and every person. This application is used in forensic science to identify the criminals. The DNA is isolated from the biological samples collected from the crime scene. DNA can be extracted from saliva, blood, hairs, semen or any body fluid. The various materials like cigarette, chewing gum or any material containing body fluids may contain DNA as it is used by the person. The person is then identified by various methods like STR, RFLP and VNTR. The estimation of the DNA is done by DPA method.


DNA, Extraction of DNA, evidence, RFLP


DNA forensic is the bed rock tool for crime investigation. It is one of the very accurate and reliable measures that have become the main source in the law enforcement. The DNA is being fundamental structure of the life and always unique for the individual. 99.99% of the human genome is similar and contains exons and introns. Only 0.1% of the DNA is different and gives the specificity to each person. During any case investigation various physical, testimonial and biological kinds of evidences may be found at the crime scene. Out of these biological evidences are very important. These include saliva, blood, semen or any biological fluid. These fluids contains variable amount of DNA and can ensure the CSIOs that the source person of DNA was present at the crime scene. However it doesn’t confirm the person as the culprit or his direct involvement in the crime, but he can’t refuse his presence on the crime scene. DNA forensic involves collection of samples with proper care and fingerprinting of DNA. The various techniques in the DNA forensic include PCR, STR, VNTR and RFLP etc. Restriction Enzyme Length polymorphism and Short Tandem Repeats gives the band pattern on the gel which is very specific. Using these technologies the individual can be identified. The DNA forensic is also used in the paternity identification and the missing cases. The qualification of DNA can be done by the Agarose gel electrophoresis method. DNA can be estimated by DPA method.


DNA forensics technique is highly authentic and very much accurate. Each person has similarities and differences in DNA sequences. DNA forensic works on the basic like extraction, isolation and identification. The source person of the DNA can be identified by using RFLP and STR.
DNA can be isolated from the various materials like cigarette, lipstick print or chewing gum used by the person. The quantity of the DNA however differs.
By above studies and results, we can conclude that, the evidences concern with direct contact with saliva like chewing gum are most important as they can provide considerable amount of DNA. Such samples should be collected with prime priority and preserved.

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