Walter M. Fitch (1929-2011)

Walter Monroe Fitch, founder of the field of molecular phylogenetics, passed away in Irvine, California, on 10 March at the age of 81. He was active until the time of his death, just finishing a book on the creationism-evolution controversy. He strongly promoted the widespread teaching of evolution. Throughout his career, Walter made substantial contributions to the theory underlying molecular evolutionary change. In the 1960s and 1970s, he developed computer algorithms to infer evolutionary relationships among organisms based on molecular data (protein and DNA sequences), as demonstrated in his classic studies on evolutionary divergence in cytochrome c. His seminal work on molecular homology and estimation of ancestral protein sequences greatly facilitated analytical procedures for describing evolutionary change. He pioneered methods to generate branching diagrams or “phylogenetic trees” to reflect the relationships among species based upon similarities and differences in their physical and/or genetic characteristics. Fitch's work had a major impact on not only biologists but also mathematicians and computer scientists. More recently, he published important contributions to understanding the molecular evolution of influenza virus and HIV. Walter was the cofounder of the Society for Molecular Biology and Evolution and its journal Molecular Biology and Evolution . He was the society's first president and editor-in-chief of the journal for 10 years. The “Walter M. Fitch Award” given by the society to the most deserving young scientists is a continuing reminder of his legacy. Walter was born in San Diego, California, on 21 May 1929. He received his A.B. in chemistry (1953) and his Ph.D. in biochemistry (1958) from the University of California, Berkeley. He was a member of the faculty of Physiological Chemistry at the University of Wisconsin, Madison, from 1962 until 1986. He was professor of Biological Sciences at the University of Southern California from 1986 to 1989, after which he was professor of Ecology and Evolutionary Biology at the University of Calfornia, Irvine until his death. His many scientific accomplishments led to multiple academy memberships including the United States National Academy of Sciences, the American Academy of Arts and Sciences, the Linnean Society of London, and the American Philosophical Society. He was awarded a number of additional international honors and honorary degrees. Walter had a marvelous and very quick mind. He has been described as a “towering intellect.” He delighted in discussing intellectually challenging scientific issues, particularly in the area of evolution. Given more to geometric rather than algebraic approaches, Walter often resorted to pencil-and-paper solutions to understand complex issues, particularly for phylogenetic problems. I assume that his development of parsimony and least-squares algorithms for phylogenetic analyses was worked out largely by hand. ![Figure][1] CREDIT: U.C. REGENTS In projects that Walter and I worked on, he was rigorous in his approach to science and meticulous in his analyses. His sequence evolution studies always involved time-consuming hand correction of alignments produced by computer algorithms. This was done laboriously and painstakingly before any subsequent analyses. Walter didn't trust global sequence-alignment algorithms and demonstrated to me and others many instances in which alignment algorithms gave erroneous results. In ways such as this, he was a wonderful mentor to younger scientists, demonstrating that they must be extremely precise with even the most fundamental aspects of a project. Those who knew him were quick to realize that Walter was highly competitive and reveled in intellectual jousting with his colleagues. He had a sharp mind and was very quick on his feet, which made him a formidable intellectual adversary. However, he was also very kind and held himself to the highest standards. Even in the vitriolic confrontations during the infamous “phenetics versus cladistics” wars in the 60s and 70s, Walter was never verbally or intellectually abusive, even when dealing with the most obnoxious individuals. At the time, both methods were proposed to resolve evolutionary relationships, the former based on overall similarity, and the latter, based on shared derived characteristics. Walter loved jazz, humor, fine wine, and good food. While a student at Berkeley, he became interested in the iconoclastic pianist Thelonious Monk and tried to play some of Monk's tunes on the piano. He always played in the key of C, which corresponds to the white piano keys, because he wasn't sure what to do with the black keys. I have always suspected that had he not become a scientist, he might have studied jazz piano. Walter also loved to share jokes and funny stories, and his involvement in practical jokes was well known. One of the best-known of the practical jokes was actually played on Walter. While he was away on sabbatical leave, a colleague and I fabricated an announcement for a seminar by a well-known biochemist disproving Fitch's classic evolutionary work on cytochrome c. There were weeks of anxiety for Walter before he learned that he was the victim of a hoax. Walter was an informal person despite his international fame as a scientist. One could easily see this in his manner of dress. His standard uniform was shorts, a T-shirt, and flip-flops. He wore this attire to meetings with the university higher administration, to scientific conferences, and just about everywhere he went. Indeed, in January one year, he appeared in his “California” attire for the 2-week-long Manfred Eigen Winter Seminar in Klosters, Switzerland. We had to stop on the way from the train station to get him properly clothed so he wouldn't freeze! Walter's methodological and theoretical achievements about estimating evolutionary relationships among species drove the maturation of the field. He was a great source of intellectual stimulation to his colleagues, a wonderful mentor to younger scientists, and a great friend to many. He will be sorely missed. [1]: pending:yes