Epigenetic changes to DNA

• Histone modification & its effect on gene expression:

  • Acetyl group is added to histone protein
  • Chromosomes wrapped around DNA unwind
  • RNA polymerase can bind to promoter region of DNA
  • mRNA can be transcribed
  • Gene is switched on
• DNA methylation

  • Methyl groups are added to DNA
  • Stops RNA polymerase from binding to the promoter region
  • mRNA is not transcribed
  • Gene is switched off
• What kind of effect do epigenetic changes have?

  Alters gene expression