Question

Below is a partial DNA sequence (the original sequence with no mutations); only the coding strand is shown.

Assume the sequence is transcribed and translated from left to right with the reading frame as indicated.

5' - | GGC | GTG | GTA | TTA | GCG | - 3'

This sequence represents a single mutation.

Mutation #3: 5' - | GGC | GTG | GTC | TTA | GCG | - 3'
Complete these sentences about this mutated DNA sequence

This mutant DNA sequence is the result of a __________ (transition or transversion?) mutation. The effect of this base substitution on the amino acid sequence results in a ___________ (nonsense, silent, or missense?) mutation.

Answer 1

The mutant DNA sequence is the result of a transversion mutation. The base substitution on the amino acid sequence results in a missense mutation.

Step-by-step explanation:

This mutated DNA sequence is the result of a transversion mutation. The transversion mutation occurs when a purine (adenine or guanine) is replaced by a pyrimidine (thymine or cytosine) or vice versa. In this case, the mutation changes guanine (G) to cytosine (C), which is a purine to pyrimidine substitution.

The effect of this base substitution on the amino acid sequence results in a missense mutation. A missense mutation occurs when a single nucleotide substitution leads to the incorporation of a different amino acid in the protein. In this case, the original codon GGT (glycine) is mutated to GTC (valine), resulting in a different amino acid being inserted into the protein sequence.