Animation showing the effects of a transition mutation in a DNA strand. In the DNA strand at left, one adenine (A) base randomly mutates into hypoxanthine (tautomerous with 6-hydroxypurine, H). This can bind to adenine, thymine (T) or cytosine (C). When the DNA replicates, this can cause the wrong base (C) to form on the new strand, which then pairs with a guanine (G) when the DNA forms a double strand again. When this mutated DNA is translated into a protein, the new base sequence will produce a mutated version of the protein it codes for, potentially causing illness or death.