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 #2: 5' - | GGC | GTG | GTA | TAA | 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 mutated DNA sequence is the result of a transversion mutation and it leads to a nonsense mutation in the amino acid sequence.

Step-by-step explanation:

The given mutated DNA sequence 5' - | GGC | GTG | GTA | TAA | GCG | - 3' is the result of a transversion mutation. This is because a purine (adenine) is substituted by a pyrimidine (thymine).

This base substitution leads to a nonsense mutation in the amino acid sequence. A nonsense mutation occurs when the substitution creates a premature stop codon, resulting in the synthesis of a truncated protein.