[1] Harvard Univ, Sch Publ Hlth, Harvard Oxford Genome Divers Project, Boston, MA 02115 USA
[2] Harvard Univ, Sch Publ Hlth, Dept Immunol & Infect Dis, Boston, MA 02115 USA
[3] Univ Oxford, Dept Zool, Oxford OX1 3PS, England
[4] Harvard Univ, Dept Organism & Evolutionary Biol, Cambridge, MA 02138 USA
[5] Norwegian Univ Sci & Technol, Dept Bot, N-7491 Trondheim, Norway