Name: Kary Mullis
Institution: Independent
Field: Invented polymerase chain reaction
Only rarely can you say of a scientist that, without him or her, the world would be a different place. But it is true of Kary Mullis, who is an integral part of the history of the genetic revolution. Mullis is an unlikely member of the biologist’s team, because he is a chemist, and one with leanings towards mathematics and physics. He has an animated curiosity and a mind that roams over many areas of science. He has invented a plastic which changes colour when exposed to ultra-violet light; he dabbles in astrology, talks about “astral plains” and LSD, and has some original ideas about Aids (he believes that the disease is not caused by HIV).
I met him at a friend’s house in a small town near his roots in North Carolina. He arrived awkwardly smiling and leaking energy like an adolescent. He is polite in the Southern way, and has the accent of his childhood, although his speech has been influenced by West Coast surfers.
He doesn’t look at you much, except when he concentrates on a question; then his eyes have an open, hypnotic quality which makes you want to look away. He likes to drink and sipped from a large glass of red wine. His face occasionally breaks into a broad smile, as if he is touched by the pleasure of his own ideas.
Back in April 1983, Mullis had applied his brilliant, unkempt mind to the problems chemists think about when they are bored. He was driving up to his cabin in Anderson Valley, California, where the redwoods grow. He began to think about a particular problem. Suddenly, he experienced a rush of thought that was to change biology and open up great possibilities, although he had no idea of its impact at the time.
This is how he describes it in his book, Dancing Naked in the Mind Field: “My little silver Honda’s front tyres pulled us through the mountains. My mind drifted back into the lab. DNA chains coiled and floated. Lurid blue and pink images of electric molecules injected themselves somewhere between the mountain and my eyes.”
The problem was how to find a chemical process to target specific lengths of DNA in billions of base pairs of genetic code. How could he get a usable quantity of this fragile, tangled material?
“I had to arrange a series of chemical reactions, the result of which would stretch the DNA,” he writes. His mind ran through a series of reactions that would define and isolate the target. Then he realised that one of the reactions, involving polymerase, a naturally occurring enzyme that takes part in forming DNA, would double the target sequence. That’s its job – copying DNA naturally. And it would repeat and repeat.
He stopped the car, found a pencil stub and paper, and began to calculate. What he was contemplating was a chain reaction and it was clear that, if it worked, it could generate a huge number of copies of the target DNA very quickly. Today PCR (polymerase chain reaction) machines can produce 100-billion copies of a targeted sequence in an afternoon.
The process is hard to understand if you are not a scientist, but to Mullis it seemed shockingly simple, so simple that he assumed it must have been already invented. Not so. All the constituent parts of PCR were known for 15 years and waiting to be put together.
It took a while for Cetus Lab, where Mullis worked, to make PCR a reality, and it subsequently challenged Mullis’s authorship, saying that it had contributed as much to the development of the process as he had. At length, when another company, the multinational giant Du Pont, tried to claim that PCR had been developed 10 years before in its laboratories, Cetus employees had to back Mullis’s account of the invention in court.
He was subsequently awarded a Nobel prize, but was only given a $10 000 bonus by Cetus. It is fair to say that relations between Mullis and his former colleagues are still sour.
I asked him whether PCR and its contribution to the efforts to map the human genome bothered him.
It was PCR that allowed the rapid identification and amplification of parts of the human genome which will be analysed and used to change humanity.
“I am basically an optimist about having control of future generations. A lot of people don’t think about this, but when I am choosing a wife I am basically choosing some traits I would like my children to have. You don’t just randomly mate with a female, you study her traits and make a selection.
“We have been breeding selectively for all time. You would like everyone to be funnier, wouldn’t you? Be smarter, happier, more successful, better at sports, have a better intellect, wouldn’t you? Those kinds of options will be available to future parents and it doesn’t bother me.”
Mullis is in his fifties, but there is a lot of the boy prodigy about him and he used to have a reputation for hell raising. Scientific conferences all over the world were enlivened by his behaviour.
Mullis’s mind is often in a state of free association, but this doesn’t seem to stop him making important connections.
“It is interesting that biochemistry developed alongside computers. If computers had not come along at about the same time as the structure of DNA was discovered, there would be no biochemistry. You always needed the computer to process the information. Without it we would have rooms and rooms full of monks writing out the sequences.”
You could say the same about PCR. Life without PCR would be very different. It is used in police investigations to identify fragments of DNA to prove a suspect’s presence at a crime scene. It has become an essential part of medical diagnostics, and in archaeology it has opened enormous possibilities.
To the Human Genome Project, Mullis has contributed one of three important elements (computing and the sequencing method being the other two).
Now he has plunged into another project, a still-secret method of diagnosing illness by machine. In Star Trek, he points out, they have a doctor who is a hologram, and not human. “That makes sense to me.”