Nirenberg  and  Matthaei (Nobel 1968) produced RNA sequences from high
   concentrations   of  ribonucleoside  diphosphates,  using  the  enzyme
   polynucleotide phosphorylase.

   The  sequence of nucleotides produced can be controlled by varying the
   concentration  of  rNDPs,  and served as the "messenger" to synthesize
   polypeptide chains in vitro.