SNPs can have variable effects
• SNPs can have no effect.  Their change can be
neutral to the protein, e.g. a silent mutation.
• SNPs can have a subtle effect, e.g lys to arg
(both are polar basic).  This is what we suspect is
happening in complex genetic diseases
• SNPs can have measurable effects (a
pronounced reduction in activity).
• SNPs can change protein function.  A new
substrate might be recognized.
• SNPs can complete eliminate the proteins ability
to function.