Around 99.9% of DNA sequences in our bodies are same in every person still sufficient DNA is present which can be used to differentiate one individual from another unless they are identical twins. DNA Profiling utilizes this very concept. It is a technique basically used in the field of forensics for identification of individuals using their respective DNA profiles. To execute the process of DNA profiling we need a DNA sample of an individual for e.g. blood, saliva semen etc. A reference sample is then used as standard to create a DNA profile by any of the following techniques: RFLP (Restriction Fragment Length Polymorphism) analysis, PCR (Polymerase Chain Reaction) Analysis, AmpFLP (Amplified Fragment Length Polymorphism), Y-Chromosome analysis and mitochondrial analysis. The profile thus obtained is compared with another sample to determine the extent of match.
How can it be used for solving criminal cases?
Few drops of blood or even a single hair found at the scene of crime is enough to get a DNA Profile. Forensic scientists can compare this profile with that of the suspected victims. If it matches then there is only one in a billion chances that they are from different persons, that too in case of identical twins.
One important concept in this aspect is Familial DNA Searching. In this new investigative leads are created in cases where DNA evidence found at the crime scene resembles that of existing offender DNA profile in a state DNA database (there are several DNA databases existing around the world; some privately held, some controlled by government). Further specially designed software is used to compare forensic profile with that of state database profiles. This may lead to some link between the profiles even if there is a distant relative DNA match.
Where India stands in use of this technology?
Though DNA profiling is one of the strongest tools in identification of culprits, India is way behind in its usage. The reason may be bureaucratic apathy and lack of understanding at the topmost level. At present India have only 15 DNA Profiling laboratories as compared to USA having 120 and South Africa more than 20 in 2007 itself. Keeping in view the negligence of our investigative authorities towards the use of this technique the Centre for DNA Fingerprinting and Diagnostics (CDFD) planned to set up a DNA Training Academy in consultation with Ministry of Home Affairs and Dept. of Biotechnology. But the proposal was stuck in between with the confusion whether the cadre should be placed under MHA or Ministry of Science and Technology.