1980-1981 Undergraduate Lab Assistant, Cytogenetics Laboratory (Charles Chrisman), Purdue University, West Lafayette, IN
1981-1985 Teaching Assistant, Introductory Genetics, Texas A&M University, College Station, TX
1986 Research Assistant, Texas A&M University, College Station, TX
1987-1990 Postdoctoral Fellow, Tampa Bay Research Institute (formerly Showa University Research Institute), St. Petersburg, FL (Gary Litman, Ph.D., supervisor)
1990-1993 Postdoctoral Fellow, Biomedical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94551 (Peter De Jong, Ph.D., supervisor)
1993 Visiting Scientist, Molecular Genetics Laboratory (Pediatrics), All Children's Hospital, St. Petersburg, FL
1993 Visiting Scientist, Human Genetics Department, Roswell Park Cancer Institute, Buffalo, NY
1993-1997 Assistant Professor of Human Genetics and Pediatrics, Center for Human Genetics, Boston University School of Medicine, Boston, MA
1997-2001 Associate Professor of Human Genetics and Pediatrics, Center for Human Genetics, Boston University School of Medicine, Boston, MA
1998-2001 Director of Developmental Genetics, Center for Human Genetics, Boston University School of Medicine, Boston, MA
1999-2001 Joint appointment (Associate Professor), Department of Microbiology and the Immunology Training Program, Boston University School of Medicine, MA
2001-2003 Associate Member, Benaroya Research Institute at Virginia Mason (formerly Virginia Mason Research Center), Molecular Genetics Program, Seattle, WA
2004-2017 Full Member, Benaroya Research Institute at Virginia Mason, Molecular Genetics Program, Seattle, WA
2004- Full Professor (Affiliate appointment), Department of Biology, University of Washington, Seattle, WA
2005-2017 Full Member, Cell and Molecular Biology Program, University of Washington, Seattle, WA
2006-2017 Training Program, Genome Sciences, University of Washington, Seattle, WA
2007-2017 Participating Faculty, Institute for Stem Cell & Regenerative Medicine, University of Washington, Seattle, WA
2017- Professor of Molecular Cell Biology, University of California-Merced, Merced, CA
2018- Faculty Equity Advisor (FEA) for the School of Natural Sciences, University of California-Merced, Merced, CA
2019- Chair, Quantitative and Systems Biology Program, University of California-Merced, Merced,CA