Macrophages are specialised cells of the immune system. They are involved not only in infection, inflammatory disease and cancer, but also in normal growth and development and tissue repair. Three main research questions for Professor Hume and his team are: 1) on a genome-wide scale, how do macrophages differentiate from their common precursors in the bone marrow under the influence of factors such as macrophage colony-stimulating factor (CSF-1) and interleukin 34 (IL34)? 2) how are mature cells of this lineage able to respond to environmental signals such as microorganisms?, and 3) what are their functions in normal embryological development and postnatal growth? David is an international authority in genome sciences, with a particular focus on the function of macrophages. He is currently the Director of The Roslin Institute at the University of Edinburgh and Professor of Mammalian Functional Genomics.