Question

What is the difference between VNTRs (Variable Number Tandem Repeats) and STRs (Short Tandem Repeats) used in forensic DNA analysis?

a) VNTRs technology allows trace DNA to be analyzed; STRs technology does not.

b) VNTRs can be amplified by PCR; STRs cannot be amplified by PCR.

c) VNTRs cannot be multiplied to obtain an allele frequency; STRs can be multiplied to obtain an allele frequency.

d) VNTRs polymorphic DNA sequence is much longer than that of STRs.

Answer 1

The main difference between VNTRs (Variable Number of Tandem Repeats) and STRs ( Short Tandem Repeats) are as following:- A) VNTRs technology allows traces of DNA to be analysed by using genetic diversity among population and in STR technology it amplifies DNA By short sequences which are easy to distinguish between two distinct persons. B) VNTRs cannot be amplified by PCR reaction due to less availability of markers to amplify the chain and STRs it can be amplified by PCR as because of its short length and high degree of polymorphism. C). VNTRs cannot be multiplied to obtain allele frequency as it violates the law of Hardy- Weinberg equilibrium. Whereas STRs can be used to multiply allele frequency as it obeys Hardy- Weinberg equilibrium. D). VNTRs polymorphic DNA sequence is much longer as it contains of 10-60 base pairs and STR DNA sequence contains only 2-6 base pairs.