So we have two reasons for our mutations to arise. Now, once we form the mutation, there are two categories of mutations. We have insertion and deletions, as well as point mutations, which are also known as base pair mutations or base pair substitutions. And let's begin by discussing insertion deletions. So, to insert something or to delete something means we're basically either placing nucleotides into the DNA or we're removing nucleotides from that DNA sequence. Now, an insertion or deletion of a number of nucleotides that is not a multiple of three, that is not a multiple of the codons that exist in the genetic code will cause the reading frame to shift, which will change the amino acid sequence of the polypeptide chain.