Thursday, February 26, 2009

Nobel Laureate: Kary Mullis

 

The Nobel Prize in Chemistry 1993.

"for contributions to the developments of methods within DNA-based chemistry: for his invention of the polymerase chain reaction (PCR) method"


Kary B. Mullis (1944 - ) won the Nobel Prize in Chemistry for the polymerase chain reaction technique. This technique is used to amplify a given stretch of DNA by repeatedly copying it several dozen times. The technique has been honed and modified and it's now a standard tool in every biochemistry and molecular biology laboratory.

Mullis shared the prize with last week's Nobel Laureate, Michael Smith, who developed the technique of in vitro mutagenesis. I'm not a big fan of awarding Nobel Prizes to those who develop a new technique. I'm much more comfortable with awards to scientists who directly advance our understanding of how life works. That's why my personal favorites are Nobel Laureates like Jacques Monod, François Jacob, Ed Lewis, Otto Warburg, Linus Pauling, André Lwoff, Barbara McClintock, and Peter Mitchell (plus many others).

Fortunately, it usually turns out that the winners of "technology" prizes are very good scientists who have also made a significant contribution to advancing our knowledge of fundamental concepts. That's certainly true of Michael Smith, Walter Gilbert, and Fred Sanger, to name just a few.

Kary Mullis was an unusual recipient in many ways. You can get a flavor for his personality by reading his Autobiography and, especially, his Nobel Lecture. There has never been a speech like that in the history of the Nobel Prize and, chances are, there will never be another.

Read about Kary Mullis on Wikipedia to see what he's been up to since he stopped being an active scientist in 1988. By the time he was awarded the Nobel Prize he was concentrating on being a writer. (This might explain the speech!)

Here's the Press Release describing Kary Mullis' contribution.

THEME:
Nobel Laureates
The "Polymerase Chain Reaction" (PCR)

The PCR technique was first presented as recently as 1985 but is nevertheless already one of the most widespread methods of analysing DNA. With PCR it is possible to replicate several million times, in a test tube, an individual DNA segment of a complicated genetic material. Mullis has described how he got the idea for the PCR during a night drive in the Californian mountains. Two short oligonucleotides are synthesized so that they are bound correctly to opposite strands of the DNA segment it is wished to replicate. At the points of contact an added enzyme (DNA polymerase) can start to read off the genetic code and link code words through which two new double strands of DNA are formed. The sample is then heated, which makes the strands separate so that they can be read off again. The procedure is then repeated time after time, doubling at each step the number of copies of the desired DNA segment. Through such repetitive cycles it is possible to obtain millions of copies of the desired DNA segment within a few hours. The procedure is very simple, requiring in theory only a test tube and some heat sources, even though there are now commercial PCR apparatuses that manage the whole procedure automatically and with great precision.


The PCR method can be used for reduplicating a segment of a DNA molecule, e.g. from a blood sample. The procedure is repeated 20-60 times, which can give millions of DNA copies in a few hours.

As has site-directed mutagenesis, the PCR method has decisively improved the outlook for basic research. The sequencing and cloning of genes has been appreciably simplified. PCR has also made Smith's method of site-directed mutagenesis more efficient. Since it is possible with PCR to perform analyses on extremely small amounts of material, it is easy to determine genetic and evolutionary connections between different species. It is very probable that PCR combined with DNA sequencing is going to represent a revolutionary new instrument for studies of the systematics of plant and animal species.

The biomedical applications of the PCR method are already legion. Now that it is possible to discover very small amounts of foreign DNA in an organism, viral and bacterial infections can be diagnosed without the time-consuming culture of microorganisms from patient samples. PCR is now being used, for example, to discover HIV infections. The method can also be exploited to localise the genetic alterations underlying hereditary diseases. Thus PCR, like site-directed mutagenesis, has a great potential within gene therapy. Without the PCR method, the HUGO project, with its objective of determining every single DNA code in, among other things, the human genetic material, would hardly be realistic. In police investigations PCR can give decisive information since it is now possible to analyse the DNA in a single drop of blood or in a hair found at the scene of a crime.

Another fantastic application is that it is possible to mass-produce DNA from fossil remains. Researchers have, for example, succeeded in producing genetic material from insects that have been extinct for more than 20 million years by using the PCR method on DNA extracted from amber. This possibility has already inspired authors of science fiction. The very popular film "Jurassic Park" is about the fear that arises when researchers using PCR recreate extinct giant reptiles.


The images of the Nobel Prize medals are registered trademarks of the Nobel Foundation (© The Nobel Foundation). They are used here, with permission, for educational purposes only.

[Photo Credit: Geschichte der PCR]

5 comments:

  1. 1. Dr. Mullis is something of a Pecks' bad boy who has spent his time since his discovery of PCR chasing beach bunnies, smoking pot, and occasionally taking hits of LSD.

    2. Does Prof. Moran think that the late William Shockley should have been awarded the Nobel Prize for his development of the transistor?

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  2. Quote:

    "I'm much more comfortable with awards to scientists who directly advance our understanding of how life works."

    And yet, in the case of biology, how would our modern understanding of the importance of molecular structure and function as related to biochemical pathways have been gained without truly deserving techniques such as X-ray crystallography? It is a fact that new science is driven by the creation of new tools to study nature such that we can eventually understand how life works. Your comments about tool builders for science are proof of what I have always experienced during my career in science, that students/researchers who spend their time creating new techniques are not as important as those using the techniques to make new discoveries. Tool builders are treated like second-class scientists sometimes. It's a bit of a chicken and egg scenario. You really can't have one without the other. How could we have got to where we are today in terms of our understanding of the world without the telescope or the microscope for example?

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  3. I've always liked the idea of Mullis getting the Nobel for PCR for the simple reason that it's a technique that could have been invented by any competent scientist who used a little imagination and who happened to be in the right place at the right time. It gives hope to all scientists that the Nobel prize is something that they can all aspire to, so long as they follow through with the necessary experiments to prove that flash of inspiration. Yes, Mullis is a bit of a lightweight compared to the greats (and thats an understatement if there ever was one) but PCR has been one of the most important technological advances in molecular biology ever and has been instrumental in creating the current post genomic scientific world.

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  4. Anonymous says,

    Your comments about tool builders for science are proof of what I have always experienced during my career in science, that students/researchers who spend their time creating new techniques are not as important as those using the techniques to make new discoveries.

    I don't think that's correct. My opinion is the minority opinion. Most scientists these days are much more interested in techniques than in concepts.

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  5. I don't think that's correct. My opinion is the minority opinion. Most scientists these days are much more interested in techniques than in concepts.

    I have to disagree. Most scientists are interested in applying the latest zippy technique, to rapidly pick all the newly-made low-hanging fruit after the heavy lifting of developing the new technique has already been done. The people who propose doing the impossible (building a new technique) get no love at all. They vastly deserve accolades for enabling the science of everyone around them.

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