Question

Choose the correct answers from the alternatives given :
If the DNA codons are CAT CAT CAT, and a guanine base is added at the beginning, then which would result?

• A. ACATCATCAT
• B. GCATCATCAT
• C. Frameshift mutation
• D. Both (b) and (c)

Answer 1

The correct option is D Both (b) and (c)

Reading or decoding of codons in a DNA is always done in a triplet. Addition of an extra nitrogenous base Guanine, in the beginning, to the existing CAT CAT CAT sequence will result in a shift in the reading frame and the sequences will be read as GCA TCA TCA T. This is called frame shift mutation wherein reading frame is altered due to the addition or deletion of a nitrogenous base.

So, the correct option is 'Both (b) and (c).