Why might a deletion mutation have a greater effect than a base substitution?

Why might a deletion mutation have a greater effect than a base substitution?

• A. Deletion causes a frameshift and alters amino acids from mutation point
• B. Substitution alters many amino acids
• C. Deletions are repaired quickly
• D. Substitution has no effect because of degeneracy

Answer: (A)

A deletion can shift the reading frame of the gene, because the genetic code is read in triplets. Removing nucleotides changes every codon downstream, so most amino acids after the mutation are altered and a premature stop codon is often introduced. This widespread change typically disrupts protein structure and function far more than a single base substitution, which usually affects only one codon and may even be silent or cause only a single amino acid change. Hence, deletions that cause a frameshift tend to have a much larger impact than base substitutions.

A deletion can shift the reading frame of the gene, because the genetic code is read in triplets. Removing nucleotides changes every codon downstream, so most amino acids after the mutation are altered and a premature stop codon is often introduced. This widespread change typically disrupts protein structure and function far more than a single base substitution, which usually affects only one codon and may even be silent or cause only a single amino acid change. Hence, deletions that cause a frameshift tend to have a much larger impact than base substitutions.