Question

A nonsense mutation in a particular gene resulted from a TGG --> TGA mutation. What compensatory mutation in the anticodon of which tRNA would restore the protein polypeptide sequence?

Answer 1

Nonsense mutation is a type of mutation which results in stop codon and premature termination of translation.

In above mutation also, TGG codes for tryptophan but TGA is a stop codon.

TGG will be coded as ACC in mRNA and TGA will be coded as ACU in mRNA.

Thus, anticodon of ACC will be UGG and that of ACU will be UGA.

Thus, there should be a mutation in anticodon of tRNA UGG as it codes for tryptophan.

Its mutation to UGA will restore the normal polypeptide sequence.