The animation shows a sequence of nucleotides A C A T A C G A that undergoes a mutation in a single base. The T mutates to a G and the new sequence reads A C A G A C G A. The mutation from a T to a G is a SNP, or single nucleotide polymorphism.
One common type of mutation that can be used to track common ancestry is the single nucleotide polymorphism (SNP). A SNP is a change of one DNA base pair into another.