Fred Sanger on Sequencing Phage x174, 1982
  Fred Sanger     Biography    
Recorded: 16 Jun 2005

Well, there was always a problem to find a small enough molecule to work on. The really the smallest animal, well, the smallest living thing and the smallest natural DNA was the, uh, —is phages, microphages. So we picked on this. It’s about five thousand units long. So that was the one we worked on. You had to split that up first because that was too big to do anything with so we—again there was another discovery which made it possible, was the use of restriction enzymes. You have to split the molecule down to smaller pieces and generally our splitting was done with acid or enzymes of various sorts and you got very complicated mixture of small fragments. But the restriction enzymes would break down the DNA into a small number of fairly large fragments of about a few hundred residues long and those were sufficiently small to use with this dideoxy method. So we had to use that and fractionate them together. That worked fairly well for the small bacteria phage, which was the first one we did. Because that took about, I don’t know, three or four years to actually work out the sequence. Of course, we had to start using computer methods and things to record the results. It was working on a much sort of more detailed techniques than previously

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.