Steve West is known for pioneering the study of enzymes that promote the intricate DNA interactions necessary for the recombinational repair of DNA strand breaks. Steve’s early work led to an understanding of DNA pairing and strand exchange by the bacterial recombinase RecA, and its human ortholog RAD51. However, his unique contribution to our understanding of recombinational repair came from his discovery of the first cellular enzyme that resolves recombination intermediates (Escherichia coli RuvC), followed by the first branch migration complex (RuvAB) in 1994.

This work set the scene for him to search for eukaryotic orthologs, culminating in his identification of yeast (Yen1) and human (GEN1) Holliday junction resolvases. His elegant biochemical approaches, coupled with cell biology, have defined the mechanisms by which human cells resolve recombination intermediates to allow efficient chromosome segregation.

Steve is the recipient of the Louis–Jeantet Prize for Medicine (2007), the Novartis Medal (2008) and the Genetics Medal (2012). He gave the Royal Society Leeuwenhoek Lecture in 2002 and the GlaxoSmithKline Medal Lecture in 2010.