Mutations

• Mutation is a random and spontaneous change in the structure of a gene, chromosome, or number of chromosomes
• Mutation is a rare, random change in the genetic material and can be inherited
• Mutation can be caused by ionising radiation or chemical mutagens like tar from cigarette smoke
• Greater doses of radiation increase the chance of mutation
• Mutations can switch different genes on or off, leading to the creation of different or faulty proteins
• Most DNA mutations do not significantly alter a protein, only slightly changing its appearance or function
• Different types of mutations can arise in DNA:

  • Substitution: a base is replaced with another, potentially resulting in a different amino acid and protein
  • Insertion: an extra base is added, potentially leading to a different amino acid and protein
  • Deletion: a base is removed, potentially resulting in a different amino acid and protein
  • Inversion: the order of bases changes, potentially leading to a different amino acid and protein
• Mutations may change protein activity in coding DNA or gene expression in non-coding DNA
• Mutations can result in phenotype changes, hidden changes, or serious consequences like genetic diseases such as cystic fibrosis