DNA fingerprinting is a technique to identify an individual by looking at unique patterns in their DNA.
- In human’s 99.9% of the base sequences of DNA are same & are referred as Bulk genomic DNA.
- The difference lies in remaining 0.1%. It is these differences which make every individual unique in their phenotypic appearance. This DNA has small stretches of repetitive sequences. They are referred as Repetitive DNA.
- The only exception is monozygotic twins.
Repetitive DNA can be separated from bulk genomic DNA by density gradient centrifugation.
- Bulk DNA forms a major peak while repetitive DNA forms several small peaks and are referred as satellite DNA.
- Satellite DNA contains short nucleotide sequences repeated thousands of time tandemly.
- Satellite DNA is divided into different categories according to their size i.e., micro-satellites, mini-satellites etc.
- Micro-satellite consists of 2 – 6 bp repeats.
- Mini-satellite consists of 10 – 100 bp repeats, they are referred as VNTRs.