[1] Univ Oxford, Dept Biochem, Oxford OX1 3QU, England
[2] Univ Bergen, Michael Sars Ctr, Thormohlensgt 55, N-5008 Bergen, Norway
[3] Univ Kansas, Dept Ecol & Evolutionary Biol, Lawrence, KS 66045 USA
[4] Univ Pittsburgh, Thomas E Starzl Transplantat Inst, Pittsburgh, PA 15261 USA
[5] Univ Pittsburgh, Ctr Evolutionary Biol & Med, Pittsburgh, PA 15261 USA
[6] Univ Pittsburgh, Dept Immunol, Pittsburgh, PA 15213 USA
[7] Univ Florida, Whitney Lab Marine Biosci, St Augustine, FL 32080 USA
[8] Univ Florida, Dept Biol, St Augustine, FL 32080 USA
[9] Univ Calif Davis, Dept Mol & Cellular Biol, Davis, CA 95616 USA