Frances Arnold

She was the daughter of a nuclear physicist and the granddaughter of a lieutenant general, and in high school she moved out, drove a cab, waited tables at a Pittsburgh jazz club and hitchhiked to Washington to protest the Vietnam War. She picked mechanical and aerospace engineering at Princeton, she said later, because it was the easiest way into Princeton and she never left. She took a year out of the degree to work in an Italian factory that made nuclear reactor parts, and filled her electives with economics, Russian and Italian while imagining a career as a diplomat or a chief executive. Then she went to Berkeley for a chemical engineering doctorate with no chemistry behind her at all. The department made her take the undergraduate courses first.

The method is easy to state and was heresy to propose: stop designing the protein and breed it. Her first major paper, in 1993, took the enzyme subtilisin E and made it work in dimethylformamide, a solvent it had no business functioning in, by running the gene through four rounds of error-prone PCR and growing the bacteria on plates of casein and DMF, then keeping whichever colonies cleared the biggest halo. She went on to evolve enzymes that work hot and cold, and enzymes that do carbene and nitrene chemistry nature never invented. The 2018 Nobel Prize in Chemistry gave her half the award, with George Smith and Gregory Winter splitting the rest, and made her the fifth woman and the first American woman to win it. She was already the first woman elected to all three American national academies.

Nothing about the years around the prize was orderly. She was diagnosed with breast cancer in 2005 and treated for 18 months. James Bailey, whom she married in 1987 and divorced in 1991, died of cancer in 2001. Andrew Lange, the Caltech astrophysicist she lived with from 1994 and had two sons by, killed himself in 2010. Her father died in 2015. In 2016 one of those sons, William Lange-Arnold, died in an accident. And 15 months after the Nobel, on January 2, 2020, Science retracted a paper she had published with Inha Cho and Zhi-Jun Jia because the results could not be reproduced — a directed-evolution result, in the field she had built, withdrawn under her own name.

The heresy became an industry. Enzymes bred rather than designed now make fuels and chemicals, and Arnold built companies on it herself: Gevo in 2005 for renewable feedstocks, Provivi in 2013 with two former students to replace pesticides with pheromones. She holds more than 40 American patents. From January 2021 she was an external co-chair of the President's Council of Advisors on Science and Technology, arguing that the job was to put science back into policymaking and rebuild public trust in it. An executive order on January 23, 2025 reconstituted the council under new co-chairs and ended the one she sat on. She still holds the Linus Pauling chair at Caltech, and has played herself on The Big Bang Theory.

Frances Arnold's life against the full span of the corpus — the fading end marks a life still in progress.

• Directed evolution of subtilisin E discovery
  Four rounds of error-prone PCR made the enzyme work in an organic solvent 1993
• SCHEMA invention
  A computational method for predicting which protein recombinations will still fold —
• Enzymatic carbene and nitrene transfer discovery
  Enzymes evolved to run chemistry with no natural precedent —
• Gevo company
  Co-founded to make fuels and chemicals from renewable feedstocks 2005
• Provivi company
  Co-founded with Peter Meinhold and Pedro Coelho to replace pesticides 2013

• July 25, 1956 aged 0 Born at Edgewood, outside Pittsburgh Her father was the nuclear physicist William Howard Arnold.
• 1974 aged ~18 Graduates from Taylor Allderdice High School She had been living on her own, driving a cab and working a jazz club.
• 1979 aged ~23 Takes a Princeton degree in mechanical and aerospace engineering
• 1985 aged ~29 Finishes a Berkeley doctorate in chemical engineering, having arrived with no chemistry
• 1986 aged ~30 Joins Caltech, where she has stayed ever since
• 1993 aged ~37 Publishes the subtilisin E work that establishes directed evolution
• 2005 aged ~49 Diagnosed with breast cancer and co-founds Gevo the same year The treatment ran 18 months.
• October 3, 2018 aged 62 Awarded half the Nobel Prize in Chemistry for directed evolution The fifth woman and the first American woman to win it.
• January 2, 2020 aged 63 Science retracts one of her papers as irreproducible

• Linus Pauling 1901–1994
  Chemist and peace activist who won two unshared Nobel Prizes in Chemistry and Peace. holds his named chair
• Jennifer Doudna b. 1964
  Biochemist who co-developed CRISPR-Cas9 gene editing, revolutionizing genetics and medicine. parallel in molecular engineering
• Joe Biden b. 1942
  46th president who enacted major infrastructure and climate legislation after decades in the Senate and vice presidency. appointed by
• Barbara McClintock 1902–1992
  Cytogeneticist who discovered transposable elements and won the Nobel Prize in Physiology or Medicine. earlier woman laureate in the sciences
• Maria Goeppert Mayer 1906–1972
  Physicist and Nobel laureate who developed the nuclear shell model, a fundamental account of atomic nuclei. earlier woman laureate in the sciences