Kary Banks Mullis (1944–2019)

Kary Banks Mullis studied the chemical processes within living organisms, known as biochemistry, during the late twentieth century in the US. He helped invent the polymerase chain reaction, or PCR. PCR is a technique used in laboratories that makes millions of copies of a specific segment of DNA, the molecule that holds the genetic instructions in every living organism. In the twenty-first century, PCR is widely used for such applications as identifying diseases, solving crimes, researching genes, growing better crops, and monitoring the environment. Despite some debates about merited recognition, Mullis received the 1993 Nobel Prize in Chemistry for inventing the PCR method. Later in his career, he took controversial stances against the accepted science of HIV and climate change. Through his work on PCR, Mullis helped to facilitate advances in numerous fields of research that rely on molecular biology, which is the study of the basic chemical and physical processes that structure living systems.

Early Life and Education

Mullis was born on 28 December 1944 in Lenoir, North Carolina, a town in the foothills of the Blue Ridge Mountains, to Bernice Barker and Cecil Banks Mullis. His mother worked in real estate and his father worked in furniture sales. He speaks fondly about his childhood in his science memoir Dancing Naked in the Mind Field, hereafter referred to as his memoir. While his parents were not scientists, at seven years old his mother bought him a chemistry set as a Christmas gift. Mullis enjoyed creating volatile mixtures with the elements and decided that science was fun. In high school, Mullis’s interests advanced to launching a frog 7,000 feet into the air on a sugar-and-potassium-fueled rocket of his own design. The frog parachuted down unharmed. According to a short autobiography written for Les Prix Nobel (The Nobel Prizes) book series, the official yearbook of the Nobel Foundation, he and his two brothers played with, or in his own words “tortured,” cows by shoving apples in the electric fence and watching them attempt to eat them without getting shocked. He attended public schools and graduated from Dreher High School in Columbia, South Carolina, in 1962.

Mullis continued his scientific education during his time earning his first university degree, and he also began his own family, which included several marriages and children. In 1966, he received a bachelor of science degree in chemistry from the Georgia Institute of Technology, also called Georgia Tech, in Atlanta, Georgia. While an undergraduate there, Mullis married his first wife, Richards Haley, with whom he had a daughter. Details of his three subsequent marriages are unclear. In an article from The Washington Post that reported on Mullis’s reputation as a womanizer, his final wife Nancy Cosgrove Mullis stated that his mother had warned her that her son did not have the qualities of a good husband. Based on an article in Esquire by Emily Yoffe, Mullis married and divorced Gail Hubbell, his second wife, sometime between the early-to-mid-1970s. He subsequently married his next wife, Cynthia Gibson, in 1976, and they had two sons. Their marriage ended in 1981, due to an affair, and in 1998 Mullis married Nancy Lier Cosgrove. The couple moved to Newport Beach, California, and remained wed until the end of Mullis’s life.

After he graduated Georgia Tech in 1966, Mullis attended the University of California, Berkeley, or UC Berkeley, in Berkeley, California, for his PhD in biochemistry and worked in the laboratory of John Brian “Joe” Neilands, a professor of biochemistry. Neilands encouraged Mullis to follow his interests as long as he wrote a thesis and got his degree, which allowed him to take a wide variety of courses in anthropology, sociology, physics, math, and music. In his memoir, Mullis states that he considered Neilands an extraordinary man and claimed his laboratory taught him most about the various aspects of life.

Even though Mullis identifies himself as a chemist in his autobiographical writings, his work spanned multiple scientific disciplines, and he developed other areas of interest. Mullis received his PhD in biochemistry in 1973. During his PhD education, he wrote an article published in 1968 in the journal Nature titled “Cosmological Significance of Time Reversal” that proposed a model of the physical universe that blended two competing theories of astrophysics, which is the study of how the universe works according to the laws of physics. After receiving his PhD, Mullis did not immediately continue his work in biochemistry. For a year he lectured at UC Berkeley and pursued postdoctoral training in pediatric cardiology, which is the study of heart conditions in children, from the University of Kansas Medical Center in Kansas City, Kansas, during the years 1973 to 1977. Mullis also wrote fiction during that time. He obtained further postdoctoral training at the University of California, San Francisco in San Francisco, California, in pharmaceutical chemistry from the years 1977 to 1979.

In 1979, Mullis was managing a bakery when he came across an old friend, Thomas White, an encounter that eventually led to Mullis’s contribution to DNA analysis. White held a postdoctoral position at the UCSF Medical Center in San Francisco, California, and soon after became a research scientist at the Cetus Corporation in Emeryville, California, where he helped Mullis obtain a job in the company’s DNA synthesis laboratory. During his time at Cetus, Mullis developed the polymerase chain reaction technique that earned him the Nobel Prize in Chemistry.

Early Professional Life

Mullis became successful in his employment at Cetus Corporation, where he worked from 1979 to 1986, but he failed to earn the respect of many of his peers. According to White, Mullis had limited experience in molecular biology, but came up with a very effective method for simplifying the production of oligonucleotides, which are short synthetic strands of DNA or RNA molecules that are used in the design of therapeutic drugs. Despite that success, according to Mullis’s memoir, he had a reputation among his Cetus colleagues for coming up with extravagant and underdeveloped proposals for his work. One of the scientists who worked alongside Mullis stated that Mullis was less well known within the company for his scientific expertise than for his eccentric behavior.

When White became director of molecular and biological research at Cetus, he promoted Mullis and placed him in charge of the DNA synthesis laboratory, where he learned about the problem of amplifying DNA. One of the primary projects at Cetus focused on developing a general DNA test for diagnosing diseases. The company’s biggest challenge was getting enough DNA to test for mutations, which is how the need for a technique that amplified those genes came into play. Amplifying DNA means that scientists can produce many copies of a specific DNA segment, making it easier to study. Having the ability to amplify DNA potentially helps in diagnosing diseases, solving crimes with forensic evidence, or studying how genes function. Without amplification, there is not enough of the specific DNA segments for scientists to work with to make attempts at those tasks effective.

Two earlier methods used for DNA-segment sequencing, or determining the order of the basic building-block nucleotide molecules of DNA, and study were not as effective as PCR. One of those methods uses restriction endonucleases, which act like molecular scissors to cut DNA into smaller pieces and separate them by size. After that, oligonucleotide probes, short strands of nucleotides designed by scientists to match a specific sequence, are used to identify and bind the target DNA. The other technique involves taking the desired segment of DNA, inserting it into a bacterial cell, and letting the bacteria make copies of it. Once inside the bacteria, nucleotides, the basic building blocks of DNA, could help create DNA strands of different lengths to be sequenced and studied. Each of those techniques could be tedious, time consuming, expensive and was not always effective. Interest in developing a better approach remained high but required a faster, simpler, and more reliable process.

At Cetus, Mullis and his team initially aimed to improve DNA sequencing methods before developing PCR. Mullis worked on making oligonucleotide probes for other laboratories. As automation advanced and machines took over some of the repetitive tasks, Mullis and his team had more time to explore new techniques for analyzing DNA. Initially, he aimed to improve DNA sequencing by refining what was known as the Sanger method, which uses dideoxynucleotide triphosphates, or ddNTPs, which are modified versions of the regular nucleotide building blocks of DNA, to halt the copying process at specific points. But Mullis realized that this approach would be impractical when dealing with the size and complexity of the human genome, which is the complete set of a person’s DNA.

While trying to develop a more time-and-cost-effective way of creating a large quantity of the target DNA segment, Mullis had a breakthrough during a drive to his cabin at night in 1983. The story is often repeated in descriptions of Mullis’s work, including his own memoir and in an article by science writer Ryan Bradley, titled “On PCR, LSD, and Science as a Wild Ride.” Mullis envisioned a method where primers, which are like oligonucleotides in that they are short strands of nucleotides, could be used to start the replication process at both ends of the target sequence. He discusses in his required Nobel Prize lecture that he realized by repeating that process with cycles of heating and cooling, it should be possible to amplify DNA, making it easier to study. That insight led to the eventual creation of PCR, despite skepticism from his colleagues at Cetus.

While Mullis had the conceptual framework for PCR, it was not until a team of Cetus experimenters applied Taq polymerase, a heat-stable enzyme that helps make copies of DNA, that the process could be fully automated, eliminating the need for constant human intervention during the heating and cooling steps. That simplified the process, allowing the target DNA to be amplified exponentially, creating massive quantities of the gene of interest in a brief period. The first successful application of PCR was a substantial breakthrough for genetics and molecular biology, dramatically increasing the efficiency of DNA analysis and enabling applications ranging from disease diagnosis to forensic science.

Notably, Mullis did not complete the first successful PCR procedure alone. That also involved the work of other peers at Cetus. Mullis came up with the fundamental concept for PCR and won the Nobel Prize for inventing the process, but many other scientists helped turn PCR into a working technology, with crucial support and funding from Cetus to make it happen. The company ultimately sold the PCR patent and related technology for 300 million dollars.

According to Mullis, his life after his time at Cetus consisted of writing, consultancy work, and becoming an immunologist for the Defense Advanced Research Projects Agency, or DARPA, which is an organization within the US Department of Defense that develops technology for military purposes. During the years 1986 to 1988, he was director of molecular biology at Xytronyx, Inc., a biotechnology company based in San Diego, California. He was also enlisted as a forensic DNA expert witness for the defense in the criminal trial of The People of California v. Orenthal James Simpson (1995) and started his own company Altermune, which focused on improving the immune system, and later on cancer research, in 2003.

Impact

Mullis’s work on PCR influenced various scientific fields, including genetics, medicine, and forensic science, by enabling the rapid amplification of DNA for many different applications. PCR’s ability to rapidly produce enormous quantities of DNA made applications much quicker, such as gene cloning, the process by which scientists can create multiple copies of a gene for further analysis. In forensic science, PCR enables DNA fingerprinting, a method that identifies individuals based on their unique DNA patterns, frequently used in solving crimes, paternity testing, and studying hereditary diseases. It has also improved diagnostic methods, such as testing for diseases like COVID-19, by allowing the detection of tiny amounts of viral DNA. PCR was instrumental in large-scale projects like the Human Genome Project, which sequenced the approximately three billion DNA base pairs, or complementary nucleotides, that make up human genetic material. In recognition of his work, Mullis received the Nobel Prize in Chemistry in 1993, highlighting the influence of his discovery in both scientific research and medical applications.

Mullis’s work in science and public statements often raised criticism, because he held views with which many in the scientific community disagreed. He publicly denied that the human immunodeficiency virus, or HIV, causes AIDS, including writing the foreword to a book titled Inventing the AIDS Virus, by Peter Duesberg, which went against the widely accepted understanding of the virus and disease. Additionally, in the 2000s he questioned the science behind climate change. Despite his published work on astrophysics, Mullis also devoted a chapter of his memoir, titled “I Am a Capricorn,” to defending astrology, which is a set of beliefs and practices based on the principle that human and personal activities are determined, and can be revealed, by the positions of celestial objects, like stars and planets. In that chapter, he states that the reader can learn more about him from simply knowing the date and location of his birth, the basis of his Capricorn astrological identification, than from the written contents of the book itself. Those opinions made him a controversial figure, with some people challenging whether his unconventional beliefs undermined his scientific achievements.

Mullis died of pneumonia on 7 August 2019 at age 74, in Newport Beach, California. He was still married to Nancy Cosgrove at the time of his death.

Sources

1. Bennett, Joan W., Ellen Daniell. “Commercializing the New Biology: A Tribute to Ronald E. Cape.” SIMB News 69 (2019): 118–124. https://www.simbhq.org/docs/simbnews/OctDec2019_SIMBNEWS.pdf (Accessed October 12, 2025).
2. Bradley, Ryan. “On PCR, LSD, and Science as a Wild Ride.” Boom California, November 12, 2015. https://boomcalifornia.org/2015/11/12/on-pcr-lsd-and-science-as-a-wild-ride/ (Accessed October 22, 2025).
3. Carlson, Peter. “Nobel Chemist Kary Mullis, Making Waves as a Mind Surfer.” The Washington Post, November 3, 1998, Style section, Final edition.
4. Editors of Encyclopaedia Britannica. “Kary Mullis,” rev. Kara Rogers. Britannica, 1999/2024. https://www.britannica.com/biography/Kary-Mullis (Accessed February 1, 2025).
5. “First Day Covers from the Collection of Edward C. Halperin, M.D., M.A.: Dr. Kary Banks Mullis.” New York Medical College Phillip Capozzi, M.D., Library. https://guides.library.nymc.edu/c.php?g=438578&p=2988278 (Accessed October 22, 2025).
6. Khandelwal, Gargi. “Dr. Kary Banks Mullis.” SciXplore, October 1, 2020. https://scixplore.wordpress.com/2020/10/01/dr-kary-banks-mullis/ (Accessed February 1, 2025).
7. McDonald, Coby. “Intolerable Genius: Berkeley’s Most Controversial Nobel Laureate.” California, December 12, 2019. http://alumni.berkeley.edu/california-magazine/winter-2019/intolerable-genius-berkeleys-most-controversial-nobel-laureate/ (Accessed February 1, 2025).
8. Morrison, Lydia and Rebecca Kucera. “Interview with Becky Kucera: What PCR and Kary Mullis Taught Me about Life.” New England Biolabs, March 7, 2018. https://www.neb.com/en-us/podcasts/taught-me-about-life (Accessed February 23, 2025).
9. Mullis, Kary B. “Cosmological Significance of Time Reversal.” Nature, 218 (1968): 663–664.
10. Mullis, Kary B. “Dr. Kary Banks Mullis.” Karymullis.com, 2002. https://www.karymullis.com/index.html (Accessed February 19, 2025)
11. Mullis, Kary B. Dancing Naked in the Mind Field. New York: Pantheon Books, 1998. https://archive.org/details/dancing-naked-in-the-mind-field/page/10/mode/2up (Accessed October 22, 2025).
12. Mullis, Kary B. “Foreword.” In Inventing the AIDS Virus, by Peter Duesberg. Washington, D.C.: Regnery Publishing, Inc., 1996. https://archive.org/details/peter-h.-duesberg-inventing-the-aids-virus-1996/page/n3/mode/2up (Accessed October 15, 2025).
13. Mullis, Kary B. “Kary B. Mullis.” In Les Prix Nobel 1993. Ed. Tore Frängsmyr, Stockholm: Nobel Foundation, 1994. https://www.nobelprize.org/prizes/chemistry/1993/mullis/biographical/ (Accessed February 1, 2025).
14. Mullis, Kary B. “Preface.” In The Polymerase Chain Reaction, eds. Kary B. Mullis, François Ferré, Richard A. Gibbs. New York: Springer, 1994.
15. Overby, Jason S. “Mullis, Kary Banks.” South Carolina Encyclopedia, 2016/2022. http://www.scencyclopedia.org/sce/entries/mullis-kary-banks/ (Accessed October 22, 2025).
16. Perry, Tony. “The O. J. Simpson Murder Trial: Defense’s DNA Expert is Called Brilliant, Offbeat: Profile: Colleagues Say Nobel Laureate Who Uses LSD and Scandalizes Scientific Meetings Loves Theatrical Behavior. D. A. May Use His Personal History and Outrageous Ways to Attack His Credibility.” Los Angeles Times, March, 29, 1995. https://www.latimes.com/archives/la-xpm-1995-03-29-mn-48420-story.html (Accessed February 23, 2025).
17. Pineda, Dorany. “Kary Mullis, Quirky Nobel Laureate Whose DNA Discovery Changed the Science World, Dies.” Los Angeles Times, August 13, 2019. www.latimes.com/obituaries/story/2019-08-13/kary-mullis-dna-nobel-prize (Accessed February 1, 2025).
18. Roberts, Richard. “Kary Mullis: A Personal Recollection.” Inference, 5 (2019). https://inference-review.com/article/a-personal-recollection (Accessed October 15, 2025).
19. Vigue, Charles L. “Kary B. Mullis.” EBSCO Knowledge Advantage, 2023. https://www.ebsco.com/research-starters/biography/kary-b-mullis (Accessed October 14, 2025).
20. Wade, Nicholas. “Scientist at Work: Kary Mullis; After the 'Eureka,' a Nobelist Drops Out.” The New York Times, September 14, 1998. https://archive.nytimes.com/www.nytimes.com/library/national/science/091598sci-mullis.html (Accessed October 22, 2025).
21. Woolfe, Lauren. “Nobel Laureate, Kary Mullis, Dies Age 74.” BioTechniques, August 16, 2019. https://www.biotechniques.com/news/nobel-laureate-kary-mullis-dies-age-74/ (Accessed February 1, 2025).
22. Yoffe, Emily. “Is Kary Mullis God? (or Just the Big Kahuna?).” Esquire, July 1994. https://www.esquire.com/news-politics/a63381703/kary-mullis-interview-1994/ (Accessed February 19, 2025).