David Botstein: A pioneering geneticist and educator 1942-2026.

David Botstein, who died on February 27, 2026, was a towering figure in the field of modern molecular genetics. His research career was largely focused on the development of methods to better understand biological systems, beginning with his early work on Salmonella phage P22 and yeast, where he exploited the use of conditional lethal mutations as suppressors to identify genes with common functions and to order them in a pathway. He is best remembered for developing restriction fragment length polymorphisms (RFLPs) as genetic landmarks for the locations of genes in the human genome, an insight that paved the way for the isolation of genes associated with disease, and the genetic mapping that was a key prelude to the sequencing of the human genome. He codeveloped DNA microarrays, as well as the algorithms necessary to gain insight from them. Botstein was a passionate educator, and throughout his career he developed novel curricula to rigorously prepare students for future careers in science. He is remembered by those who worked with him as a man of great warmth, who cared deeply for his colleagues and students. His contagious enthusiasm for science, and life in general, was evident in everything he undertook.