Sarah decided to do a PhD with Cyrus Chothia at the Medical Research Council Laboratory of Molecular Biology (LMB), also in Cambridge, after reading his paper on 1,000 families of proteins.
“This was the mid 1990’s and was at the beginning of bioinformatics, when many people didn’t really understand the point of it. The sequences of lots of bacterial genomes were becoming available, and I wanted to use those genomes to understand proteins, and compare them with known protein structures. We were surprised to see how long and complex these bacterial proteins were, and also how few protein families there were. We could then use the data to see how genes evolved.”
Sarah’s PhD research led to a post-doctoral position in London at UCL with Janet Thornton, moving onto studies into how biological systems could be represented as networks.
“Lots of DNA sequences had recently become available, and we could use them to reveal networks of proteins, how these proteins combined with each other. This new network theory was really exciting, and so powerful to be able to visualise the molecular interactions between proteins.”
After two years, in 2001, Sarah was recruited back to the LMB in Cambridge as a group leader, where she spent the next 12 years using network theory to look at the evolution of transcription regulatory networks - how genes are switched on and off in cells. Unusually, within her group she combined theoretical, computational work, with wet-lab work. The biochemical experiments could test the computational theories, which proved very successful. By 2013, she had published more than 70 papers with her many co-workers and collaborators, including foundational work on the assembly of protein complexes. She had also married her long-term partner and had two children.