Question

Which of the following sequences shows a frameshift mutation compared to the wild-type mRNA sequence? a) wild-type 5’-AUGCAUACAUUGGAGUGA-3’ mutant 5’-AUGCAUACAGAGUGA-3’ b) wild-type 5’-AUGCAUACAUUGGAGUGA-3’ mutant 5’-AUGCAUACGUUGGAGUGA-3’ c) wild-type 5’-AUGCAUACAUUGGAGUGA-3’ mutant 5’-AUGCAUACAUCUGGAGUGA-3’ d) wild-type 5’-AUGCAUACAUUGGAGUGA-3’ mutant 5’-AUGCAUGUGACAUUGGAGUGA-3’

Answer 1

The correct answer is: c) wild-type 5’-AUG CAU ACA UUG GAG UGA-3’ mutant 5’-AUG CAU ACA UCU GGA GUGA-3’

A frameshift mutation is a type of genetic mutation caused by insertions or deletions of a number of nucleotides that is not divisible by three. Because of the triplet codon reading frame is changed. A frameshift mutation is different than single-nucleotide polymorphism where one nucleotide is replaced, rather than inserted or deleted.

Answer 2

Option C:

wild-type 5’-AUGCAUACAUUGGAGUGA-3’

mutant 5’-AUGCAUACAUCUGGAGUGA-3’

Step-by-step explanation:

Frame shift mutation as the name indicates are such type of mutation in which a nucleotide insertion or deletion occurs in such as way that it alters the complete sequence of 3 codon sets. As we know all the genes are translated in sets of 3 codons, which determine a specific amino acid sequence. So, if a frame shift mutation occurs, unlike a point mutation it can effect many amino acid sequences and ultimately a whole protein.

If we look at option C:

wild-type 5’-AUG CAU ACA UUG GAG UGA-3’

mutant 5’- AUG CAU ACA UCU GGA GUG A-3’

An insertion of a base Uracil occured at the end of 3rd codon due to which whole sequence of codon triplets were altered. This changed all next codons and ultimately all next amino acids will be altered.

Hope it helps!