About the Authors
Department of Molecular Biology and Genetics, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, United States of America
Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
The authors have declared that no competing interests exist.
The author(s) have made the following declarations about their contributions: Conceived and designed the experiments: XCL BKT. Performed the experiments: XCL. Analyzed the data: XCL BKT. Wrote the paper: XCL JCS BKT.