Question

Basis of DNA fingerprinting is ___________.

• A. Double helix
• B. Error in base sequence
• C. Polymorphism in sequence/satellite DNA
• D. DNA coiling
• E. DNA replication

Answer 1

The correct option is C Polymorphism in sequence/satellite DNA

DNA fingerprinting is based on sequence polymorphisms which are minor sequence differences (mostly single base-pair changes) between individuals. Restriction enzymes can digest the whole genome into DNA fragments of specific length based on the location of restriction sites in the genome. Sequence polymorphism affects recognition sites for restriction enzymes which in turn causes variation in the size of DNA fragments produced by digestion with a particular restriction enzyme. These variations are restriction fragment length polymorphisms (RFLPs) which are detected by Southern blotting. For this purpose, restriction enzyme digested DNA samples are sorted by gel electrophoresis followed by Southern blotting. Finally, radioactive probes are washed over the nylon surface to allow their joining to any DNA fragments of the same composition.

Thus the correct answer is option C.