1 K. C. Kent Lloyd is a professor at the Department of Surgery, School of Medicine, and the Director of the Mouse Biology Program, University of California, Davis, 2795 Second Street, Suite 400, Davis, CA 95618, USA. Email: kclloyd@ucdavis.eduPeter N. Robinson is a professor at Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany, and The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06032, USA. Email: peter.robinson@jax.orgCalum A. MacRae is the Chief of cardiovascular medicine at Brigham and Women's Hospital and an associate professor of medicine at Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. Email: camacrae@bics.bwh.harvard.edu.