1. DNA finger printing is one of the most accurate methods for placing an individual at the scene of a crime has been a finger print.
2. The DNA finger print is unique for every person and can be extracted from traces of sample from blood, saliva, hair etc. By using this method, we can detect the individual specific variation in human DNA.
3. In this method, the extracted DNA is cut at specific points of varying lengths in the formation of DNA fragments of varying lengths which were analysed by technique called gel electrophoresis. This method separates the fragments based on their size. The gel containing the DNA fragments are then transferred to a nylon sheet using a technique called blotting. Then the fragments will undergo autoradiography in which they were exposed to DNA probes.
4. A piece of X-ray film was then exposed to the fragments, and a dark mark was produced at any point where a radioactive probe had become attached. The resultant pattern of marks could then be compared with other samples.
5. DNA finger printing is based on slight sequence differences between individuals. These methods are providing decisive in court cases world wide.
