Which type of mutation occurs when extra nucleotides are inserted into a DNA sequence?

• A. Deletion mutation
• B. Substitution mutation
• C. Insertion mutation
• D. Frameshift mutation

Answer: (C)

An insertion mutation occurs when extra nucleotides are added into a DNA sequence. This increase in nucleotide number can lead to a change in how the genetic code is read during translation, potentially resulting in altered proteins. The insertion can disrupt the normal reading frame of the DNA sequence, leading to significant functional changes in the resulting proteins.

While the option of a frameshift mutation often accompanies an insertion because the addition of nucleotides shifts the way the entire sequence is grouped into codons, specifically referring to the addition of extra nucleotides aligns with the definition of an insertion mutation. This distinction is crucial in understanding the mechanics of genetic mutations and their impacts on protein synthesis.