Question

Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?
A) a deletion of a codon
B) a deletion of two nucleotides
C) a substitution of the third nucleotide in an ACC codon
D) a substitution of the first nucleotide of a GGG codon
E) an insertion of a codon

Answer 1

Answer:

The correct answer is option B) "a deletion of two nucleotides".

Explanation:

A frameshift mutation is a type of genetic modification caused by the insertion or deletion of one or more nucleotides in a position that results in changing the sequence at which codons are translated in the ribosome. Frameshift mutations have the most serious effect on the polypeptide products since it results in changing completely the sequence of the protein. A deletion of two nucleotides after the AUG start of translation would result in a frameshift mutation, therefore this mutation would have the most serious effect on the polypeptide product.