Question

The following samples of rice plants were collected from the rice field for DNA profiling.

Study the DNA profiles and identify the correct alternative.

• A. C and D are identical to each other
• B. All four are identical to each other
• C. A and D are identical to each other
• D. A and B are identical to each other

Answer 1

The correct option is D A and B are identical to each other

DNA from the rice strains was extracted carefully from all four samples and were separately treated with restriction endonuclease. Unequal lengths of DNA fragments are obtained by cutting the DNA at specific sites. Gel electrophoresis for all the samples is carried out. The samples are then stained to reveal the banding patterns.
Since the DNA bands are located at the same position in the case of A and B, this signifies that similar fragments are produced after restriction digestion of the samples. This indicates that they carry almost identical sequences and are most closely related.

C and D do not have all bands at the same position so they are not identical. A and D are also not identical since the DNA bands of both the samples are not in the same position.