Cutting DNA with restriction enzymes, James Watson
Interviewee: James Watson.
James Watson discusses the breakthrough that allowed scientists to cut DNA.
(DNAi Location: Manipulation > Revolution > Players > James Watson > The big breakthrough)
Big breakthrough was finding ways to cut DNA molecules at specific spots, not randomly sheared, we'd always studied DNA which had been broken randomly, you had to break it at specific points, that was the real problem, how to cut at defined spots along the DNA molecule. And we thought all molecules which cut DNA, the degradative enzymes, cut randomly. So we didn't know how to proceed. And then suddenly, or over a couple of years, it began to appear there was a class of enzymes that cut DNA molecules at quite specific points.
In 1944, Avery and MacLeod, and McCarty purified the transforming principle of Fred Griffith's earlier experiment with pneumocossus bacteria. By a process of elimination, these scientists showed that DNA was the factor that caused genetic transformation.