Dr. Samuel H. Wilson has been Acting Director of the National Institute of Environmental Health Sciences (NIEHS) and the National Toxicology Program of the National Institutes of Health (NIH) since August 20, 2007. Wilson earned an A.B. in chemistry at the University of Denver in 1961 and his M.D from Harvard University in 1968. He served as founding director of the Sealy Center for Molecular Science at the University of Texas, Galveston (1991-1996). While a professor at the University of Texas, Wilson was credited with first isolating the enzyme polymerase beta. He joined NIEHS in 1996 as Deputy Director and Chief of the DNA Repair and Nucleic Acid Enzymology section.