Read the passage carefully and answer the given questions.
DNA fingerprinting
Polymorphism in DNA sequence is the basis of genetic mapping of the human genome as well as of DNA fingerprinting. DNA fingerprinting involves identification of differences in some specific regions in the DNA sequence called repetitive DNA. It works on the principle of polymorphisms in DNA sequences. The repetitive DNA are separated from bulk genomic DNA. The bulk DNA forms a major peak and the other small peaks are referred to as satellite DNA. These repetitive/satellite DNA sequences show a high degree of polymorphisms and form the basis of DNA fingerprinting.
Which one of the following techniques is involved in DNA fingerprinting?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Gel electrophoresis
Option (1) Gel electrophoresis — Correct. After restriction enzymes cut the DNA, the pieces are put in a gel and an electric current is passed. The pieces separate according to their size, because the smaller pieces move farther. These separated pieces are then blotted and probed to give the band pattern.
Option (2) Chromatography — Incorrect. Chromatography separates the parts of a mixture as a solvent carries them along a paper or a column, as with leaf pigments. It is not one of the steps of DNA fingerprinting.
Option (3) Recombinant DNA Technology — Incorrect. Recombinant DNA technology joins a gene with a vector and puts it into a host to make a product. DNA fingerprinting uses a restriction enzyme too, but it only compares DNA. It never makes a recombinant DNA.
Option (4) ELISA — Incorrect. ELISA (Enzyme Linked Immuno-sorbent Assay) works on the antigen-antibody reaction. It is used to diagnose infections such as HIV, not to compare the DNA of two people.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
DNA Fingerprinting – …
