Final answer:
An addition mutation, or insertion mutation, occurs when extra nucleotides are added to a DNA sequence, which can result in a frameshift mutation that alters the function of the encoded protein and possibly leads to genetic diseases.
Step-by-step explanation:
What is an Addition Mutation?
An addition mutation, also known as an insertion mutation, occurs when one or more nucleotides are inserted into a DNA sequence. This type of mutation alters the normal sequence of nucleotides and can potentially change every subsequent codon following the site of mutation, leading to a frameshift mutation. This shift can have significant effects on the protein produced, potentially resulting in a nonfunctional protein. Imagine the analogy of missing or adding a letter in a sentence, which can change the meaning of every word that follows. An addition mutation is a type of point mutation, which also encompasses deletions and substitutions of nucleotides.
In sum, addition mutations can drastically change the genetic instructions encoded by DNA and have a profound impact on an organism's phenotype, possibly leading to genetic disorders or diseases if they occur in a crucial gene.