From my old blog:
(photo: evilutionarybiologist.blogspot.com)
John Dennehy has a post on the very powerful, and now-ubiquitous, technique known as the polymerase chain reaction.
I left a comment on his blog, asking him to settle a few questions. Namely:
1) Did Mullis come up with the technique itself, or merely the use of Taq polymerase?
2) Was he actually on LSD when he came up with whatever he came up with, or is this one of those urban legends grad students tell each other as they wait for their thermocycler to ramp down to 4C and ∞?
3) I remember hearing that during the first manifestation of the PCR – the sort of thing shown in the picture – a thermolabile polymerase was NOT used, and someone actually had to replenish the reaction with fresh polymerase after each denaturation step. Was this true, and how does it relate to (1)?
Dennehy responds:
1. Its clear that Mullis did not “invent” PCR because that was mostly due to work done by late Kjell Kleppe, a Norwegian scientist working at Nobel Laureate H. Gobind Khorana’s famous Institute for Enzyme Research at University of Wisconsin from 1968 to 1970. He presented his results at a Gordon Conf. and published in JMB in 1971. I think Mullis should be credited with “refining” the technique in addition to the idea of TAQ. How much of this can be credited to his Cetus colleagues is debatable and probably will never be known for sure.
2. In a Q&A interview published in the September 1994 issue of California Monthly, Mullis said, “Back in the 1960s and early ’70s I took plenty of LSD. A lot of people were doing that in Berkeley back then. And I found it to be a mind-opening experience. It was certainly much more important than any courses I ever took.” During a symposium held for centenarian Albert Hofmann, Hofmann revealed that he was told by Nobel-prize-winning chemist Kary Mullis that LSD had helped him develop the polymerase chain reaction that helps amplify specific DNA sequences. I’m not sure this means that Mullis was tripping when he came up with PCR, but may have found “inspiration” for the idea, whatever that means.
3. Yes it’s true. That’s essentially what Kleppe did, but the technique did not catch on since you had to add more polymerase after each round.
Speaking of PCR, all you hardcore aficionados may also appreciate this little number:
In case you’re too young to remember, they are parodying this:
In case you’re interested, here is a “behind the scenes” video.
There’s now a whole bunch of knockoff lipsync videos out there now. Check here, here and here.
Sad…
Tags: PCR
