What is the smallest number of nucleotides that must be added or subtracted to alter the reading frame?

Question: What is the smallest number of nucleotides that must be added or subtracted to alter the reading frame?
- Keywords:
  nucleotides
Asked by kingo1000 to SarahJane on 26 Jun 2013.
- Sarah-Jane Walsh answered on 26 Jun 2013:
  
  Wow that’s a hard question! But i’m pretty sure any number of nucleotides will alter the reading frame unless they are in multiples of 3 because that’s what forms a tripled codon.
  
  So the smallest would be 1…. Is that your homework =P

Question: What is the smallest number of nucleotides that must be added or subtracted to alter the reading frame?