1. Department of Medical Informatics and Clinical Epidemiology, Oregon Health and Science University, Portland, Oregon 97239, USA;
2. Linus Pauling Institute, Oregon State University, Corvallis, Oregon 97331, USA
3. Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
4. The Jackson Laboratory, Farmington, Connecticut 06032, USA
5. School of Medicine, School of Public Health, and School of Nursing, Johns Hopkins University, Baltimore, Maryland 21205, USA