Nobel laureates Jennifer Doudna and Emmanuelle Charpentier first met at a 2011 conference in Puerto Rico, where both gave talks about a then little-known biological system called CRISPR-Cas9, which bacteria use as an immune defence. They immediately hit it off. "She was coming to CRISPR from a very different perspective than I was," Doudna says. "And I liked her."The two women began working together across fields and continents -Doudna is a biochemist at the University of California, Berkeley. Charpentier, a microbiologist, was at Umeå University in Sweden at the time. Over the next year, they adapted the CRISPR system to edit DNA in any species. The technique is now used to genetically modify organisms for Emmanuelle Charpentier (left) and Jennifer Doudna (right) won the 2020 Nobel Prize in Chemistry -the first all-female team to win a Nobel.