If a deletion occurs in a coding region, what type of mutation is most likely to result?

If a deletion occurs in a coding region, what type of mutation is most likely to result?

• A. Point mutation
• B. Silent mutation
• C. Frameshift mutation
• D. Chromosome translocation

Answer: (C)

When nucleotides are deleted in a coding region, the reading frame is disrupted because the genetic code is read in groups of three bases (codons). Removing bases shifts every downstream codon, changing which amino acids are added from that point on and often creating a premature stop signal. This widespread change in the amino acid sequence and typical early termination is what defines a frameshift mutation. If the deleted segment were exactly a multiple of three, the frame wouldn’t shift and you’d get an in-frame deletion instead, which is a different outcome. The other options don’t fit because a point mutation is a single base change, a silent mutation preserves the same amino acid, and a chromosome translocation involves larger-scale rearrangements.

When nucleotides are deleted in a coding region, the reading frame is disrupted because the genetic code is read in groups of three bases (codons). Removing bases shifts every downstream codon, changing which amino acids are added from that point on and often creating a premature stop signal. This widespread change in the amino acid sequence and typical early termination is what defines a frameshift mutation. If the deleted segment were exactly a multiple of three, the frame wouldn’t shift and you’d get an in-frame deletion instead, which is a different outcome. The other options don’t fit because a point mutation is a single base change, a silent mutation preserves the same amino acid, and a chromosome translocation involves larger-scale rearrangements.