Intact    yeast
   chromosomes  can  be separated using pulsed field gel electrophoresis,
   where the the voltage is periodically switched among 3 directions.

   This technique can separate very large DNA pieces such as 15 of the 16
   yeast chromosomes shown here, with the largest chromosomes at the top.

   DNA  from  the  chromosomes  can  then be cloned and stored in genomic
   libraries.