Gene Mutations

  • recall that all variants arise from mutations, and that most have no effect on the phenotype, some influence phenotype and a very few determine phenotype
  • recall that mutations occur continuously. Most do not alter the protein, or only alter it slightly so that its appearance or function is not changed
  • recall that a few mutations code for an altered protein with a different shape (to include that an enzyme may no longer ft the substrate binding site or a structural protein may lose its strength)
  • recall that not all parts of DNA code for proteins. Non-coding parts of DNA can switch genes on and off, so variations in these areas of DNA may affect how genes are expressed
  • describe how genetic variants may influence phenotype in coding DNA by altering the activity of a protein (to include DNA related to mutations affecting protein structure, including active sites of enzymes
  • describe how genetic variants may influence phenotype in non-coding DNA by altering
    how genes are expressed (to include DNA related to stopping transcription of mRNA – use of terms promoter, transcription factor not required)