Bacteria have been defending themselves against viruses for billions of years. Jennifer Doudna helped turn one of those ancient defenses into a way to edit DNA. The discovery began with a question about how nature works. It left her confronting another: with this ability, what should we choose to change?
I first photographed Jennifer in July 2021 at the Innovative Genomics Institute in Berkeley. Summer fog hung over the hills outside. Inside, the pandemic had interrupted the familiar rhythms of university life. No students clustered in the hallways. The usual movement between laboratory benches was absent. We made portraits in a building designed to bring scientists together, at a time when simply sharing a room required care.
Nine years earlier, Jennifer, Emmanuelle Charpentier, and their colleagues had shown how a bacterial enzyme called Cas9 could be directed to cut DNA at a chosen sequence. In bacteria, RNA guides Cas9 to matching sequences in invading viral DNA. The researchers demonstrated that they could redesign the guide, directing the enzyme to a different target.
That made the system programmable. Instead of engineering a new protein for each target, a biologist could change the RNA guide. Once Cas9 made its cut, the cell’s repair machinery could be used to disrupt a gene or, under suitable conditions, introduce a new sequence. Editing DNA was already possible. CRISPR made many experiments easier and less expensive, allowing far more laboratories to undertake them.
Jennifer and Emmanuelle shared the 2020 Nobel Prize in Chemistry for developing a method for genome editing. By then, researchers were exploring how it might help people with inherited diseases.
In 2023, the FDA approved the first treatment using CRISPR, for certain patients with sickle cell disease. Doctors collect blood stem cells after medication moves them into the bloodstream. Editing a regulatory region of their DNA allows the cells to produce more fetal hemoglobin, an oxygen carrying protein whose production normally declines after birth. Following chemotherapy, the edited cells are returned to the patient, where they can produce red blood cells less prone to sickling. The treatment can prevent the severe pain crises that have disrupted patients’ lives for years.
Jennifer had also helped bring the risks into public discussion. In 2015, she joined scientists and other colleagues in calling for restraint on clinical uses of heritable genome editing while its safety and ethical consequences were examined. Editing a patient’s blood cells affects that patient. Changes made to embryos used for reproduction could be inherited by descendants, extending the consequences beyond anyone able to consent.
The second time I photographed Jennifer was at her home, where she stood beside her husband, biochemist Jamie Cate. She was relaxed and quick to smile, and our conversation returned to the implications of her work. After the nearly empty institute, I enjoyed seeing her in her own surroundings, with someone who shared her life and understood the science.
A photograph from that session became her Nobel portrait.
