Q. What do mean by DNA ﬁngerprinting? Discuss its principle and various applications.
DNA ﬁngerprinting (also called DNA proﬁling or DNA typing) is a technique to identify and compare sets of DNA
It is now used for a lots of purposes but forensics is the major ﬁeld in which it is used
It was invented by a British geneticist, Sir Alec Jeffreys in 1977 at Leicester university
For the ﬁrst time it was used in 1983 and then in 1986, to identify the rapist and murderer of two girls in Narboroug, Leicestershire
Now modern instruments are used for this process, which can identify hundreds of samples in a single day
Principle of DNA Fingerprinting
Human genome contains 3 billion base pairs which are arranged in a particular sequence that gives us a unique identity. But still the DNA is every human is almost similar. 90% of the DNA is same in every human beings (about 99.9% nucleotide bases are exactly same in human beings). DNA ﬁngerprinting is based upon the rest 10% difference in the human DNA This method is done by matching the uncommon sequence of humans with the suspect’s unique sequence.
Sources of DNA
DNA can be obtained from
2. semen traces/vaginal swab from cloths
DNA ﬁngerprinting has got a lots of applications
1. This procedure is mostly used in forensics to identify the criminals
2. It is also used for the paternity test
3. It is used in the study of breeding patterns of animals facing the danger of extinction
4. It is also used in determining lineages of humans and other animals to ascertain the process of evolution by checking the “genetic markers” which are passed from the ancestors
5. It is used to diagnose the genetic disorders and hereditary disorders like haemophilia, sickle cell anaemia, cystic ﬁbrosis etc
6. It is also used to determine about the antibiotics to which bacterias are resistant
Sample Collection: Picking up DNA samples from a crime scene with sterile tools and storing samples in a proper manner are crucial for the evidence to stand a judicial test. And this is where India’s police forces have a lot of catching up to do with counterparts overseas. The Aarushi Talwar murder case of 2008 is a prime example
Challenge from unregulated labs which offer delay, false reports of DNA.
There is also a serious paucity of capacity for DNA ﬁngerprinting in the country. While several states have their own forensic labs, DNA ﬁngerprinting is available only at a few places — Maharashtra, West Bengal, Delhi, Hyderabad and Chandigarh.
Laws in India regarding DNA ﬁngerprinting: The DNA Proﬁling Bill to regulate human DNA proﬁling and establish standard procedures for DNA testing, lapsed with the end of the term of 16th Lok Sabha .As there are currently no legal mechanisms for identifying missing persons and victims of disasters, the new Bill seeks to regulate human DNA proﬁling and establish standard procedures for DNA testing.
Proper training of state police personnel for protecting and collecting DNA samples during crime investigation
Government should develop infrastructure bases for DNA ﬁngerprinting for example, upgradation of forensic labs etc
A comprehensive law for the use and regulation of DNA-based technology