Question

Alec Jeffreys used ………. as a genetic marker.
A. Humulin
B. Radioactive probe
C. RFLP
D. VNTR

Answer 1

Hint: Sir Alec John Jeffreys is a British geneticist. He introduced the techniques of genetic fingerprinting and DNA profiling. This system is now used across the world in forensic science to assist police detective work and to resolve paternity and immigration disputes.

Complete answer:
Dr. Alec Jeffreys, is a geneticist from the University of Leicester in Great Britain. He was studying hereditary diseases in families. He was concentrating on the research, in which he tried to find a method whereby using the genetic links between individuals so that fatherhood and immigration problems can be solved.
Sir Jeffreys used the ‘Restriction Fragment Length Polymorphism (RFLP)’ technique to explore Deoxyribonucleic Acid (DNA). Later he observed the repetitive patterns of DNA which are known as Variable Number of Tandem Repeats (VNTRs). This pattern was found to be present in all human beings but that they varied in length for each individual. After the discovery of VNTR, he understood that this variation could be used to accomplish the identity of a person. He called this technique ‘genetic fingerprinting’. Dr. Jeffreys also revealed that the genetic fingerprint is specific and unique to each individual and this pattern cannot be found in any other person of the world except for identical twins. Today, DNA identity testing is one of widely used techniques in the field of forensics and paternity identification.
In the process of genetic fingerprinting, a small amount of DNA is collected from the samples. Then the PCR technique is applied on DNA for the purpose of expansion of the DNA molecules present in the sample and a large sequence of DNA is received. RFLP analysis process is applied to the testing sample for identifying the repeated sequences and a specific sequence to the Variable Number Tandem Repeats is detected which becomes that individual's DNA profile. This VNTR is used as genetic markers.

Therefore, the correct option is option D.

Note: Dr. Alec Jeffreys is a British scientist, who invented the method of genetic fingerprinting. In his research he tried to use the unique character of DNA i.e. the DNA never be the same between two individuals. His purpose for the research to solve the fatherhood and immigration disputes. In his test he used the VNTR as a genetic marker. In the present day, this technique becomes the most useful in forensic sciences to identify the criminals.