Arthur Dale Riggs (August 8, 1939 – March 23, 2022) was an American geneticist who worked with Genentech to express the first artificial gene in bacteria. His work was critical to the modern biotechnology industry because it was the first use of molecular techniques in commercial production of drugs and enabled the large-scale manufacturing of protein drugs, including insulin. He was also a major factor in the origin of epigenetics. Riggs was a professor of biology and, in 2014, founding director of the Diabetes & Metabolism Research Institute of City of Hope National Medical Center. He was the founding dean of City of Hope's graduate school, the Irell & Manella Graduate School of Biological Sciences. He was also director emeritus of the Beckman Research Institute of City of Hope National Medical Center, which he headed from 2000 to 2007. Riggs served on the board of trustees at the Keck Graduate Institute of Applied Life Sciences. In 2006, Riggs was elected to the National Academy of Sciences. Early life and education Riggs was born in Modesto, California, near his family's home in Ceres, California, on August 8, 1939. After the family lost their farm during the Great Depression, they moved to San Bernardino, California, where Riggs attended San Bernardino High School. He helped his father, who managed a trailer park, to build and fix things. His mother, a nurse, gave him a chemistry set to encourage his interest in chemistry and biology. Riggs earned his undergraduate degree in chemistry at University of California, Riverside in 1961. He conducted his doctoral thesis work at the California Institute of Technology with Herschel K. Mitchell, obtaining a Ph.D. in biochemistry in 1966. Mammalian DNA replication As graduate students at Caltech, he and Joel A. Huberman collaborated on work that later led to a classic paper on mammalian DNA replication, which was published in 1966. They wanted to use radioactive nucleotides to tag replicating DNA and then use photographic film to produce physical images that capture what happens during replication. Their advisors were not interested in the experiment when Huberman and Riggs proposed it, and the students continued the work on their own. Using their method, they were able to measure the rate of DNA replication. The results indicated that chromosomal DNA contained many sections, which replicated independently, and that replication occurred in both directions at each section's origin. The results were important and helped