Arno Gunther Motulsky (5 July 1923 – 17 January 2018) was a professor of medical genetics and genome sciences at the University of Washington. Through his research, writing and mentoring, he helped create and define the field of medical genetics. He is also known as the "father of pharmacogenomics" (the study of how drug action and metabolism differ among people due to genetic variability) based on his report in 1957 of negative drug responses in some patients depending upon their genetics at critical enzymes.[2]