Fred Sanger on Critical Moments in Research
  Fred Sanger     Biography    
Recorded: 16 Jun 2005

Well, I think the most important thing was when I developed the method for DNA sequencing with the terminators and the new fractionation method that would separate according to size. The dideoxy method, essentially, I think, was the most important breakthrough. That was quite a lot of luck in it, I mean, because it seemed, you know, we had done a lot of fractionation. That was always a very important thing. We never before found a method that would fractionate exactly according to size and this method just suddenly we found that we could fractionate exactly according to size and this made a big effect on me.

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.

http://en.wikipedia.org/wiki/Frederick_Sanger