DNA Mutations Notes

Small-scale Mutations

  1. Point mutations - A change to just one nucleotide base pair. Results in:
    1. Silent mutation - Change of base pair codes for the same amino acid !
    2. Missense mutation - the replacement base pair is a valid amino acid codon. Most common point mutation.
    3. Nonsense mutation - This substitution creates a stop codon that usually creates a non-functional protein.
  2. Insertion / deletion - nucleotide is added to / removed from the DNA
    1. Frameshift mutation - causes shift of codon reading and results in non-functional polypeptide.