1. Institute of Evolutionary Biology, University of Edinburgh , Edinburgh , United Kingdom
2. Department of Embryology, Carnegie Institution for Science, Howard Hughes Medical Institute Research Laboratories , Baltimore, MD , USA
3. Tree of Life Programme, Wellcome Sanger Institute , Cambridge , United Kingdom
4. Department of Zoology, University of British Columbia , Vancouver , Canada
5. Department of Molecular Biology and Genetics, Aarhus University , Aarhus , Denmark