Fred Sanger on The Chain Termination Method: Sanger Sequencing
  Fred Sanger     Biography    
Recorded: 16 Jun 2005

That method involved just taking, labeling the ends of the molecules and fractionating on the system, which would fractionate exactly according to size. In all this work the most technical problem is to fractionate substances and separate them. We did most of the breakthroughs were dependent on new developments of fractionation. In the early work it was the partition chromatography, which helped us very much. But the particular method that helped us particularly in the DNA work was this fractionation on silica gel, I think it was silica gel, using acrylamide gels at a certain condition where you could separate things exactly according to size and this was something we never had before. We just were lucky, I think, in a way that we found a method which you could separate things on a column by electrophoresis according to size. And this meant that you could take four samples, one labeled—you take a fragment and you take four samples of it and each one is labeled at the end of what we called the C-terminal end …5’ end. And, you run these side by side so you get three columns and each one has terminate at different end so you can read off the sequence directly from your experiment. It’s complicated to describe without pictures and things. But it meant one could read off these sequences much more rapidly than by the partial hydrolysis methods which we had used previously for proteins and early studies on the RNA and DNA. That was something of a breakthrough, really. It was lucky though, somebody working in the lab was using fractionations on acrylamide gels and this system just happened to separate exactly according to size. Which was a small technical problem, but it worked.

Frederick Sanger, OM, CH, CBE, FRS (born 13 August 1918) is an English biochemist and twice a Nobel laureate in chemistry. In 1958 he was awarded a Nobel prize in chemistry "for his work on the structure of proteins, especially that of insulin". In 1980, Walter Gilbert and Sanger shared half of the chemistry prize "for their contributions concerning the determination of base sequences in nucleic acids". The other half was awarded to Paul Berg "for his fundamental studies of the biochemistry of nucleic acids, with particular regard to recombinant-DNA".

He is the fourth (and only living) person to have been awarded two Nobel Prizes, either wholly or in part.