1. WildCare Institute, Saint Louis Zoo, One Government Drive, Saint Louis, Missouri 63110, USA
2. Charles Darwin Foundation, Puerto Ayora, Santa Cruz, Galápagos, Ecuador
3. Department of Biology, University of Missouri—St. Louis, 8001 Natural Bridge Road, Saint Louis, Missouri 63121, USA
4. Epidemiology, Genetics, and Pathology Laboratory, Puerto Ayora, Santa Cruz, Galápagos, Ecuador
5. Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland