Question

The normal sequence of mRNA transcribed from a particular DNA strand is
5'-AUG GUC GGA CUG GGC GUC UAA-3'.
As a result of mutation in DNA, the mRNA sequence is changed to
5'-AUG GUC UGA CUG GGC GUC UAA-3'.
What type of mutation is this?

• A. silent
• B. missense
• C. nonsense
• D. frameshift

Answer 1

The correct option is C nonsense

Mutation refers to the change in the nucleotide sequence in DNA of an organism. It can be of many types.

A type of mutation in which the resulting codon is a stop codon is called nonsense mutation. In the given sequence the 3rd codon GGA is mutated and is changed to UGA which is a stop codon. It causes the termination of protein synthesis.

In a missense mutation, the substitution of a nucleotide results in incorporation of an amino acid different from the original one.

In frameshift mutation, the reading frame of the template changes due to addition or deletion of nucleotides.

A silent mutation is a change in the nucleotide sequence without a subsequent change in the sequence of amino acids of the corresponding protein. Hence the function of the protein produced from a gene which has a silent mutation will not be affected.