nucleotides
Similar to chromosomal alteration mutations, deletion or insertion mutations add or remove genetic information. Small deletions or insertions in the DNA will alter the reading frame. Deletions remove one or more nucleotides from the DNA, whereas insertions add one or more nucleotides into the DNA. These mutations in the coding region of a gene may also alter the splicing of the mRNA, known as a splice site mutation . Mutations which alter the reading frame are known as frameshift mutations . Splice site mutations and frameshift mutations both can dramatically change the mRNA, altering the final protein product.