Question

Given the original mRNA codon “UAC”, what is an example of a mRNA codon that would result in a silent mutation?

Answer 1

In mutation 1, the codon CUC changes to CUU. As both the codons code for the same amino acid i.e., leucine, thus, this mutation is silent mutation and does not affect individual having it.

In mutation 2, a base G is inserted between codons CAU and CUU and changes the frame of reading of genetic code and changes the entire polypeptide coded by it. It is a frameshift mutation.

In mutation 3, codon UAC is changed into a termination codon UAA which stops polypeptide synthesis, hence such type of mutation is called nonsense mutation.

So, the correct answer is 'Silent mutation → 4 Frameshift mutation → Nonsense mutation'.