DNA insertion mutation. Animation showing an insertion mutation in the replication of DNA (deoxyribonucleic acid). As the DNA unravels, a helicase enzyme (red) is shown moving along the helix, separating the complementary strands. Labels appear showing the genetic code, the sequence of the nucleotide bases along a strand (cytosine, C, blue; guanine, G, yellow; adenine, A, green; thymine, T, red). A DNA polymerase enzyme is shown replicating a new strand and inserting a new guanine nucleotide base (red area). The new complementary strands are formed, completing the replication process and the animation zooms in on the mistake (a mutation). Adjacent groups of three bases, known as codons, code for the production of amino acids (the basis of proteins). The insertion has shifted the other bases along (red area). This changes the codons and is a type of frame-shift mutation. |