(a) Expand VNTR and describe its role in DNA fingerprinting.

(b) List any two applications of DNA fingerprinting technique.

DNA fingerprinting is a technique developed by Alec Jeffreys. It is used for determining the nucleotide sequence of a segment of DNA, which is unique to every individual. As 99.9% of the base sequence is the same among humans, this technique helps to distinguish humans from one another by identifying differences in repetitive DNA.

(a) VNTRs refer to Variable number tandem repeats. It belongs to a category of satellite DNA called as minisatellites. The size of the VNTR varies from 0.1 to 20 kb. A small DNA sequence is arranged tandemly in many copy numbers. The number of repeats shows a high degree of polymorphism (variation at the genetic level). This sequence normally do not code for any proteins, but they form the basis of DNA fingerprinting.

(b) DNA fingerprinting technique has a number of forensic applications:

•In case of disputes, this technique forms the basis of paternity testing. As the polymorphs are inheritable, they serve as very useful identification tools.

•Another application involves criminal identification and forensics. DNA collected from a crime scene can help to identify the criminal and the victim.