Final answer:
An insertion mutation occurs when an extra nucleotide is added to the DNA sequence, causing a shift in the reading frame. This can have significant effects on proteins.
Step-by-step explanation:
One example of an insertion mutation is when an extra nucleotide is inserted into the DNA sequence. Let's take the mRNA sequence UGCAAUGGUAAUAACACAUGAGGCCUGAAC as an example. If an A nucleotide is inserted after the start codon AUG, the sequence becomes UGCAAUGGUUAAUAACACAUGAGGCCUGAAC. This insertion changes the reading frame, and all the codons that follow it are affected.
Original mRNA: UGC-AUG-GUA-AUA-ACA-UGA-GGC-CUG-AAC
Mutated mRNA: UGC-AUG-GUU-AAU-AUA-ACA-UGA-GGC-CUG-AAC
Insertion mutations can have dramatic effects on proteins because they change the amino acid sequence. When an insertion occurs, it shifts the reading frame, resulting in different codons being read. This can lead to the production of a completely different protein or the premature termination of protein synthesis.