Kary Banks Mullis was born in Lenoir, North Carolina, in 1944, the son of Cecil Banks Mullis and Bernice Alberta (Barker) Fredericks. 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. In Berkeley at that time there was growing interest in hallucinogenic drugs; Mullis taught a controversial neurochemistry class on the subject. His thesis adviser, Joe Nielands, told Omni that as a graduate student Mullis was "very undisciplined and unruly; a free spirit." Yet at the age of twenty-four, 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, where he stayed for four years. In 1977, he assumed a postdoctoral fellowship at the University of California, San Francisco. After two years there, discouraged by universities and uncertain what to do with his life, he left academia.
In 1979, he accepted a position as a research scientist with a growing biotech firm, Cetus Corporation, in Emeryville, California, which was in the business of synthesizing chemicals used by other scientists in genetic cloning. At Cetus, Mullis was bored by the routine demands of corporate life. In spite of this, while there he designed polymerase chain reaction (PCR), a fast and effective technique for reproducing specific genes or DNA fragments that is able to create billions of copies in a few hours. Reproducing deoxyribonucleic acid (DNA) had long been an obstacle to anyone working in molecular biology. The most effective way to reproduce DNA was by cloning, but however much of a scientific advance this process represented, it was still cumbersome in certain respects. DNA strands are long and complicated, composed of many different chromosomes; the problem was that most genetic engineering projects were tasks that involved tiny fragments of the DNA molecule, almost infinitesimal sections of a single strand. Cloning works by inserting the DNA into bacteria and waiting while the reproducing bacteria creates copies of it. The cloning process is not only time-consuming, it replicates the whole 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 allowing scientists to amplify or enlarge parts of the DNA molecule for further study.
Mullis remembers that it took a long time to convince his colleagues at Cetus of the importance of this discovery. "No one could see any reason why it wouldn't work," he told Popular Science. "But no one seemed particularly enthusiastic about it either." Once they had become convinced of its importance, however, PCR became the focus of intensive research at Cetus. Scientists there developed a commercial version of the process and a machine called the Thermal Cycler; 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, and the technique, as one microbiologist told Time, "can reproduce genetic material even more efficiently than nature."
The selectivity of the PCR process, as well as the fact that it is simple and economical, have profoundly changed the course of research in many fields. In the field of genetics, the process has been particularly important to the Human Genome Project--the massive effort to map human DNA. Nucleotide sequences that have already been mapped can now be filed in a computer, and PCR enables scientists to use these codes to rebuild the sequences, reproducing them in a Thermal Cycler. The ability of this process to reproduce specific genes, thus effectively enlarging them for easier study, 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. There are many other medical applications for PCR, and it 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 found in bogs. PCR can also answer questions about more recent history; it has been used to identify the bones of Czar Nicholas II of Russia, and scientists at the National Museum of Health and Medicine are preparing to use PCR to amplify DNA from the hair of Abraham Lincoln, as well blood stains and bone fragments, in an effort to determine whether he suffered from a disease called 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. Some have suggested the PCR can be used to create tags or markers for industrial and biotechnological products, including oil and other hazardous chemicals, to ensure that they are used and disposed of in a safe manner.
Cetus awarded Mullis only $10,000 for developing the PCR patent, which the corporation later sold for $300 million. Frustrated both by the size of this award and the restrictions the company continued to place on his scientific research, Mullis left Cetus in 1986 and ultimately became a private biochemical research consultant. In 1993, Mullis was awarded the Nobel Prize. He has been married and divorced three times and is the father of three children. Mullis currently serves as vice president of molecular biology at Burstein Technologies, Inc. in Irvine, California. He published an autobiography, Dancing Naked in the Mind Field, in 1998.
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