Question

DNA polymorphism that has been used to develop the DNA fingerprinting technology is based upon

• A. Variation in the number of tandemly repeated sequence
  
• B. Unique nucleotide bases present in genome
  
• C. Number of protein coding genes
  
• D. Single nucleotide polymorphism
  

Answer 1

The correct option is A Variation in the number of tandemly repeated sequence


DNA polymorphism

• DNA polymorphism refers to the variations in the genetic level (mutations) that can be inherited and present at high frequency in a population.
• It can be either SNP (Single Nucleotide Polymorphism) or VNTR (Variable Number Tandem Repeats).

Single nucleotide polymorphism

• SNP is formed when any alteration or mutation occurs in a single nucleotide (A, T, C, or G).
• The point mutation-like substitutions, insertions or deletions in a single nucleotide represent SNP.

Variation in the number of tandemly repeated sequence

• Variable Number Tandem Repeat (VNTR) is also called minisatellites. They are surrounded by conserved restriction sites. The small stretches of DNA sequences are tandemly repeated. The number of copies of these repeats varies with individuals.
• They show a high degree of polymorphism, so their size ranges from 0.1 to 20 kb.

DNA fingerprinting

DNA fingerprinting is a technique that allows the identification of variations which are unique to each organism using a VNTR probe that shows a very high degree of polymorphism.

Final answer: (b) Variation in the number of tandemly repeated sequence