What type of mutation involves the addition of an extra nucleotide?

The correct answer involves a mutation characterized by the addition of an extra nucleotide, known as an insertion mutation. This type of mutation occurs when one or more nucleotide bases are inserted into the DNA sequence. This additional nucleotide can disrupt the reading frame of the gene, potentially altering the entire sequence of amino acids that follows, which can significantly impact the resulting protein.

Insertion mutations can lead to various consequences, including coding for a different protein or creating a stop signal that prematurely terminates protein synthesis. Understanding insertion mutations is crucial in genetics and molecular biology as they can be implicated in various diseases and can contribute to genetic diversity.

While frameshift mutations are directly related to insertions (as they cause a shift in the reading frame due to an insertion or deletion), the specific question asks for the type of mutation itself, which is best described as an insertion.