What happens if you copy paste 
  the 'legs selector' part of a 
  mouse HOX gene into the fruitfly 
  Homeobox:

    'In fact, when the mouse Hox-B6 
     gene is inserted in Drosophila, 
     it can substitute for Antennapedia 
     and produce legs in place of 
     antennae'	

Mother of God, is that ever strange.