Mullis, Kary Banks
Mullis, Kary Banks
American biochemist Kary Banks Mullis is famous in forensic science circles as the designer of the polymerase chain reaction (PCR ). PCR is a fast and effective technique for reproducing specific genes or deoxyribonucleic acid (DNA ) fragments that is able to create billions of copies in a few hours. Widely available because it is now relatively inexpensive, PCR has revolutionized not only the biotechnology industry, but also many other scientific fields and it has important applications in forensic science and law enforcement.
Mullis was born in Lenoir, North Carolina, on December 28, 1944. He entered Georgia Institute of Technology in 1962 and studied chemistry. As an undergraduate, he created a laboratory for manufacturing poisons and explosives . He also invented an electronic device stimulated by brain waves that could control a light switch.
Upon graduation from Georgia Tech in 1966 with a B.S. degree in chemistry, Mullis entered the doctoral program in biochemistry at the University of California, Berkeley. At the age of 24, he wrote a paper on the structure of the universe that was published by Nature magazine. He was awarded his Ph.D. in 1973 and he accepted a teaching position at the University of Kansas Medical School in Kansas City. In 1977, he assumed a postdoctoral fellowship at the University of California, San Francisco. In 1979, he accepted a position as a research scientist with a growing biotech firm, Cetus Corporation, that was in the business of synthesizing chemicals used by other scientists in genetic cloning.
In the late 1970s, the most effective way to reproduce DNA was by cloning. The cloning process is not only time-consuming, but it replicates the whole DNA strand, increasing the complexity. The revolutionary advantage of PCR is its selectivity; it is a process that reproduces specific genes on the DNA strand millions or billions of times, effectively amplifying or enlarging parts of the DNA molecule for further study.
A commercial version of PCR and a machine called the Thermal Cycler have been developed. With the addition of the chemical building blocks of DNA, called nucleotides, and a biochemical catalyst called polymerase, the machine would perform the process automatically on a target piece of DNA. The machine is so economical that even a small laboratory can afford it.
In the field of genetics, the PCR process has been particularly important to the Human Genome Project, a huge undertaking to map human DNA. The ability of this process to reproduce specific genes has made it possible for virologists to develop extremely sensitive tests for acquired immunodeficiency syndrome (AIDS), capable of detecting the virus at early stages of infection. PCR has been particularly useful for diagnosing genetic predispositions to diseases such as sickle cell anemia and cystic fibrosis.
PCR has also revolutionized evolutionary biology, making it possible to examine the DNA of woolly mammoths and the remains of ancient humans. PCR has been used to identify the bones of Czar Nicholas II of Russia. Scientists are preparing to use PCR to amplify DNA from the hair of Abraham Lincoln, as well as bloodstains and bone fragments, in an effort to determine whether he suffered from Marfan's syndrome.
In law enforcement, PCR has made genetic fingerprinting more accurate and effective. It has been used to identify murder victims, and to overturn the sentences of men wrongly convicted of rape.
In 1988, Mullis became a private biochemical research consultant. In 1993, he won the Nobel Prize in chemistry.
see also DNA; Fingerprint; PCR (polymerase chain reaction).