Tim completed his PhD at the Wellcome Sanger Institute, UK, under the auspices of Mike Stratton, Iñigo Martincorena and Sam Behjati. His studies focused on using somatic mutations to trace normal human development and the origins of childhood cancers. His work involved cataloguing patterns of somatic mutations across human tissues and reconstructing phylogenies of early embryonic development. He also showed that the human placenta tolerates vast amounts of genomic damage and that Wilms tumors often derive from early, embryonal precursor clones.

In the Getz lab, Tim is furthering this line of research to precisely study the evolution of normal cells into cancer cells. He is involved in efforts to accurately detect somatic mutations and reconstruct lineages in single cells.