• The lactase gene (LCT) is turned off in many adults by the reduction of DNA transcription.
  • The exact mechanism for reducing LCT transcription is not yet known, but it could be mediated by changes in activator or repressor molecules.
  • The lactase persistence mutation changes the expression of LCT by increasing the gene’s transcription. One mechanism by which it does this is to increase the interaction of an activator molecule with the enhancer region of the gene.