Question

A nucleotide substitution within the protein coding sequence of a wild type gene results in a truncated,, completely nonfunctional proteins. This mutation can be characterized as all of the following EXCEPT:

forward mutation

frameshift

amorphic

nonsense

Answer 1

Ans) The correct answer is Forward mutation.

Frameshift mutation (by addition,deletion of nucleotides) in the ORF i.e open reading frame by nucleotide substitution can change the sequence such that it produce truncated or non-functional protein.

Amorphic or null mutation can lead to even complete non-functional protein.

Nonsense mutation is the mutation which occurs such that a nucleotide substitution can result in the STOP codon leading to premature termination of protein synthesis. (Example If AGA codon is changed to UGA (stop codon) due to the substitution of A in AGA to U in UGA is known as nonsense mutation.

Forward mutation is incorrect because it converts wild type allele into mutable allele i.e genotype is getting changed here.