About the Authors

Ke Zheng
P. Jeremy Wang


Affiliation Department of Animal Biology, Center for Animal Transgenesis and Germ Cell Research, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: KZ PJW. Performed the experiments: KZ. Analyzed the data: KZ PJW. Wrote the paper: PJW.