About the Authors
Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, United States of America
The authors have declared that no competing interests exist.
AE conceived and directed the work. JC conducted the whole-genome bioinformatic analyses, constructed all of the transgenic animals, and performed in situ hybridization assays. AE and JC analyzed all the data. YT assisted with characterization of the sog locus. AE wrote the paper. All authors commented on the manuscript.