Kary Mullis is an unusual scientist. Declares love surfing as much as of science and its interventions in reference to topics such as AIDS, climate change or the hole in the ozone layer do not leave anyone indifferent. But they are controversial opinions that have earned him international recognition, and the Nobel Prize in Chemistry in 1993, but the development of one of the most important tools in the field of Molecular Biology in history: the PCR.
Mullis received his Ph.D. in Biochemistry at the University of Berkeley, Calif., and was in this city where he began working in 1979 for the biotechnology company Cetus Corporation, whose work made it easier to get to his brilliant idea. In the ceremony of the Nobel Prize, Kary Mullis said that was a Friday night while driving to his cabin in the mountains and while his girlfriend slept in the passenger seat of his car, when that idea appeared before him as a revelation.
PCR is the acronym for chain reaction polymerase (Polymerase Chain Reaction) and is a technique that can multiply in a team called the thermal cycler, a specific fragment of DNA. Before the advent of PCR in the world of molecular biology were used to amplify DNA cloning vectors called, but they had the disadvantage of relying on cell division the organism in which they were included. On the other hand, what does is take advantage of PCR, in vitro, the characteristics of a protein called DNA polymerase whose function is to multiply in the cell nucleus, the genetic material. This protein will bind to a given DNA fragment and will double in the thermocycler at a rate of about one thousand nucleotides of DNA structural units per minute. Then, the reaction mixture is subjected to high temperatures to separate the newly formed chains, so that by lowering the temperature again, the protein will have twice as molds to make copies. Thus, at least theoretically, from a single DNA molecule after forty cycles have more than one billion molecules alike.
But this technique presented in the beginning a problem, and that is to make the DNA strands are separated from each other completely, the reaction mixture should be at 95 ยบ C, making the polymerase is distorted and therefore had to be adding protein in each cycle, making the technique was more expensive and much slower than it is today. And today is that the problem is saved by using thermostable DNA polymerase, obtained from micro-organisms used to living at high temperatures as the case of Thermus aquaticus, originally isolated from hot springs of Yellowstone Park.
After saving these initial hurdles, the directors of Cetus Corporation believed in the possibilities of technical and Kary Mullis rewarded with extra pay of $ 10,000. Years later, the company sold the patent for the technique of 300 million. Since then the business around the PCR has not only grown and it is difficult to imagine a molecular biology lab without a team to develop this technique. And so common it has become the PCR to movies and television have been infected with the terminology that surrounds it. Movies like Jurassic Park or series as CSI or House would have no meaning without it and not hard to find frames in which the PCR reaction becomes the protagonist.
Today, PCR is a common technique while indispensable both in basic and applied research. Utilities such as sequencing, identification of individuals-in-forensic medicine, development of phylogenetic trees or paternity test, give an idea of \u200b\u200bthe magnitude of the art. It is also a powerful diagnostic tool in medicine, used in the detection of congenital diseases and to determine the presence of virus or bacteria in a biological sample. Quite a few
criticizing each public intervention Kary Mullis and say he is just running a scientist who had the vision and clearly point to develop the PCR. There are also those who use the Nobel Prize was awarded to justify everything he says. The only certainty is that his name has been inextricably linked to that of the profile technique developed in the twentieth century in the field of Molecular Biology, and that is indisputable.
0 comments:
Post a Comment