Mark L. Wheelis is an American microbiologist. Wheelis is currently a professor in the College of Biological Sciences, University of California, Davis. Carl Woese and Otto Kandler with Wheelis wrote the important paper Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya that proposed a change from the Two-empire system of Prokaryotes and Eukaryotes to the Three-domain system of the domains Eukaryota, Bacteria and Archaea.Wheelis's research interests include the history of biological warfare.