Dna Fingerprinting

DNA fingerprinting is a technique that identifies individuals based on differences in specific regions of their DNA that vary greatly from person to person. It depends on Variable Number of Tandem Repeats (VNTRs), a class of satellite DNA in which short base sequences are repeated many times, with the number of repeats differing among individuals. These length polymorphisms produce unique band patterns when DNA is cut, separated, and probed. The option of coding exons of housekeeping genes is incorrect because such genes are highly conserved and nearly identical across individuals, providing little discriminating variation. Ribosomal RNA genes are likewise conserved due to their essential structural role, so they cannot distinguish individuals reliably. Telomerase enzyme regions relate to chromosome-end maintenance and ageing, not to the hypervariable repeat profiling used in fingerprinting. As outlined in NCERT Class 12, Chapter 6 (Molecular Basis of Inheritance), VNTR polymorphism forms the basis of forensic identification and paternity testing. As a verification step, only highly polymorphic, individual-specific sequences like VNTRs can give the discriminating patterns required, confirming them as the basis of DNA fingerprinting.