Question

How does gel electrophoresis relate to DNA Fingerprinting?

Answer 1

Hint: DNA Fingerprinting is the technique of comparing DNA samples. The Gel electrophoresis is the method of separating DNA fragments by charge and thereby allowing the comparison of DNA samples which is used in DNA Fingerprinting

Complete answer:
Gel electrophoresis is the method of separation of DNA on the basis of their charge. Since the DNA is negatively charged so the DNA will move from the negative electrode to the positive electrode and the speed of the movement of the DNA fragments depends upon the size of the fragments. The smaller fragment moves faster compared to the larger fragment thereby separating the fragments which are visualized as bands on the gel under UV light. This creates a very unique pattern for the DNA sample.

DNA fingerprinting also known as DNA profiling is the method of comparison of the two DNA samples. This is based on the principle that 99.9% of the human DNA is the same while there are variations in the 0.1% of the DNA. Human satellite DNA shows the variable short term repeats (VNTRs) which are different in every individual. Therefore on the treatment of the DNA sample with the restriction enzymes, the cleavage sites of every sample will be different and will result in different sets of fragments.

So when the two samples of DNA are treated with restriction enzymes they will result in a different pattern on the Gel electrophoresis if they are from a different source. The same pattern will be observed if the sample of DNA is from the same source.

This method of DNA fingerprinting is used in crime investigation to compare the DNA sample collected from the site of investigation with the suspects or Paternity or maternity disputes.

Note: The application of DNA fingerprinting is as follows,
1)It can be used for paternity and maternity tests
2)It helps in criminal investigations - Even a small blood sample can help in the process of investigation
3)It helps in person identification