About the Authors
University of British Columbia, Department of Zoology, Vancouver, British Columbia, Canada
University of Virginia School of Medicine, Department of Biochemistry and Molecular Genetics, Charlottesville, Virginia, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: JCM IMH RJR. Performed the experiments: JCM SS. Analyzed the data: JCM IMH RJR. Wrote the paper: JCM RJR.