As all living things contain DNA, and all DNA exhibits variability both among and within species, any biological material associated with a legal case carries in it information about its source (Mark A. Jobling e'tal).The major advantage of DNA based technique is requirement of very small amount of sample like drop of body fluid, cigarette butts , or hair is enough to determined the identity of criminal or person related to crime.
There is almost century old history of forensic genetics started with human ABO blood group polymorphisms. It was used for quite long time but having few drawbacks it was not used quite frequently in present investigations. The major back trough occurred in 1984 when Alec Jeffreys identified the hyper variable loci known as MINISATELLITE. The banding pattern obtained from this micro satellite known as DNA fingerprinting and was widely used since it discovery. The only drawback of this system is complicated data and difficulty to interpret. Than
Development of 'single-locus probes' (SLPs) here it revealed only a single, highly polymorphic, restriction fragment length polymorphism. And hence simplifying interpretation. In Typical SLP based investigation four SLPs were used successively to probe a Southern blot, yielding eight hyper variable fragments per individual.( Mark A. Jobling e'tal). ...Show more