title: Obituary: Walter Fitch and the orthology paradigm.
authors.forename: Eugene V
authors.initials: EV
authors.lastname: Koonin
mesh_terms: D000465:Algorithms; D019143:Evolution, Molecular; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D010802:Phylogeny