Gene Mutation

• What is a gene mutation?

  A change in the arrangement of bases in an individual gene or in the structure of chromosomes which changes the arrangement of genes
• Mutation can

  Lead to alteration or absence in proteins, or a genetic disease
• Mutations don't

  Always cause genetic disease, as they can be found in either somatic cells or gametes
• Mutations

  occur randomly at a low rate, and source of variations
• Mutagens

  • Radioation (X-ray, nuclear, UV)
  • Mutagenic chemicals
  • Extreme heat
• Substition

  A change in one base
• Deletion and Instertion

  One base is removed or inserted, causes a frame shift, changes hte amino acid sequence and so will result in different amino acid sequence
• Non-sense

  When substitution results in transcription ending prematurely because the substitution resulted in a stop codon being formed
• Mis-sense mutation

  When a change in base leads to a different amino acid being implemented into the primary structure
• Silent

  When the change in base still codes for the same amino acid, therefore not altering the polypeptide that is synthesised