What is DNA fingerprinting? Explain its importance in taxonomy.
Answers
This is also known as ‘DNA PROFILING’ o ‘DNA TYPING’. DNA fingerprinting is a technique to identify a person on the basis of his/her DNA specificity.
The practice of using thumbs impression of a person, as an identifying mark is very well known since long.
The study of finger, palm and sole prints is called dermatoglyphics and it has been a subject of human interest.
But, the concept of DNA fingerprinting is totally a new approach in the field of molecular biology. Sir Alec Jeffreys (1985-86) invented the DNA fingerprinting technique at Leicester University, United Kingdom.
Meaning:
DNA of an individual carries some specific sequence of bases, which do not carry any information for protein synthesis. Such nucleotide base sequences are repeated many times and are found in many places throughout the length of DNA. The number of repeats is very specific in each individual. The tandem repeats of short sequences are called ‘mini satellites’ or ‘variable number tandem repeats’ (VNTRs). Such repeats are used as genetic markers in personal identity.
Technique:
1. The first step is to obtain DNA sample of the individual in question.
2. DNA is also isolated from bloodstains, semen stains or hair root from the body of the victim or from victim’s cloth even after many hours of any criminal offence. Even it can be obtained from vaginal swabs of rape victims. The amount of DNA needed for developing fingerprints is very small, only a few nanograms.