Recently, DNA testing was conducted on the bones recovered from the Mehrauli forest area in connection with the Shraddha Walkar murder investigation.
- The DNA testing has now confirmed a positive match with Shraddha’s father.
About DNA fingerprinting
- DNA fingerprinting was first developed in 1984 by Alec Jeffreys in the UK, after Jeffreys discovered that no two people could have the same DNA sequence.
- The UK achieved the world’s first conviction based on DNA evidence in a case of rape and murder.
- DNA is deoxyribonucleic acid, the molecules in cells that determine the genetic characteristics of all life. It takes the form of a double helix (two strands coiled together).
- Each person’s DNA, except for identical twins, is unique.
- Human cells contain 23 chromosomes (packets of DNA) from the father and 23 from the mother.
- Each DNA strand contains a unique sequence or code of genetic information. But while most of DNA shows only slight variation from one person to the next, certain areas, called ‘minisatellites’ (short sequences of chemical building blocks) show variation in the numbers of repeat units (or stutters) unique to each person.
- DNA fingerprinting is a technique that simultaneously detects lots of minisatellites in the genome to produce a pattern unique to an individual. This is a DNA fingerprint.
- By analyzing selected DNA sequences (called loci), a crime laboratory can develop a profile to be used in identifying a suspect.
- DNA can be extracted from many sources, such as hair, bone, teeth, saliva, and blood.
- Since there is DNA in most cells in the human body, even a minuscule amount of bodily fluid or tissue can yield useful information. Samples may even be extracted from used clothes, linen, combs, or other frequently used items.
- In India, Lalji Singh, who had been in the UK from 1974 to 1987 on a Commonwealth Fellowship, developed DNA fingerprinting for crime investigations at the Centre for Cellular and Molecular Biology (CCMB) in Hyderabad.
- Lalji Singh is known as “the father of DNA fingerprinting in India.”
- In 1989, DNA fingerprinting was first used in a case by the Kerala Police.
- From the 2000s onwards, the technology became a staple in rape cases where vaginal swab samples were matched with semen samples from suspects.
