About the Authors

Keith A Hultman

Affiliation Department of Genetics, Washington University School of Medicine, Saint Louis, Missouri, United States of America

Nathan Bahary

Affiliation Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America

Leonard I Zon

Affiliations Department of Pediatrics, Children's Hospital, Boston, Massachusetts, United States of America , Howard Hughes Medical Institute, Boston, Massachusetts, United States of America

Stephen L Johnson

To whom correspondence should be addressed. E-mail: sjohnson@genetics.wustl.edu

Affiliation Department of Genetics, Washington University School of Medicine, Saint Louis, Missouri, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

KAH and SLJ conceived and designed the experiments, analyzed the data, and wrote the paper. KAH performed the experiments. NB, LIZ, and SLJ contributed reagents/materials/analysis tools.