1 HudsonAlpha Institute for Biotechnology, Huntsville, Alabama, United States of America.
2 Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America.
3 Department of Biology and the Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America.
4 Departments of Population and Quantitative Health Sciences, Institute of Computational Biology, Case Western Reserve University, Cleveland, Ohio, United States of America.