• A gene mutation occurs when there is a change in the sequence of bases in the DNA of a gene. Bases may be added, deleted or substituted.
  • A mutation produces a change in the DNA codons and is likely to result in a polypeptide with a different amino acid sequence.
  • Change in polypeptide structure may alter the way the protein functions. As a result of mutation, enzymes may function less efficiently or not at all, causing a metabolic block to occur in a metabolic pathway.
  • New alleles arise from mutations in existing alleles.
  • Mutations in reproductive cells can be passed on to following generations, but mutations in body cells will only affect the tissues in which they occur.
  • Mutations occur naturally at random, but the rate of mutation is increased by mutagens such as radiation and some organic chemicals.