Gregory M. Cahill, associate professor of biology and biochemistry at the University of Houston died Tuesday, December 23, 2008, at Bush Intercontinental Airport while waiting for a flight. He was 50. Greg is survived by a sister, Elizabeth Bjorlin of Prior Lake, Minn.; and four brothers, Paul Cahill of Janesville, Minn., Byron "Pat" Cahill of Kasson, Minn., Jared Cahill of Prior Lake and William Cahill of Eagan, Minn.

Greg was born July 17, 1958, in Mankato, Minn., the son of Paul Cahill and Cynthia Spangle Cahill. He grew up in Janesville, Minn., and graduated from Janesville High School in 1976. He earned a Bachelor of Science degree from the College of Biological Sciences at the University of Minnesota in Minneapolis/St. Paul in 1980. He earned his doctorate in biology and neuroscience at the University of Oregon working with Professor Michael Menaker, where he examined the pharmacology and physiology of synaptic input into the mammalian suprachiasmatic nucleus from the retinohypothalamic tract using an isolated slice preparation.

After earning his doctorate, Greg did postdoctoral work with Professor Joseph Besharse at Emory University, and later moved with Joe to the University of Kansas Medical Center in Kansas City, where he became a Research Assistant Professor. During this time, Greg worked to establish many of the neurochemical features of melatonin secretion from the Xenopus laevis retina, especially its control by circadian oscillators and external neural modulators such as dopamine, and the effect of light on this system. A study of particular importance and ingenuity during this time appeared in Neuron in 1993, in which Greg and Joe established that the circadian oscillator controlling retinal melatonin secretion was located within the photoreceptor layer.

Greg joined the Department of Biology and Biochemistry at the University of Houston in 1994 as an Assistant Professor, and was promoted to Associate Professor in 2001. In our department, Greg continued his work on retinal circadian oscillators in Xenopus, and produced a series of careful analyses of second messenger systems controlling melatonin secretion that were under the control of light, dopamine, and the circadian oscillator. During this time, Greg also initiated the work for which he is best known, the analyses of the genetics of vertebrate circadian oscillators in the zebrafish Danio rerio. To do this, Greg and his students had to devise novel optical methods for monitoring their locomotor behavior over long periods of time, and then to complete forward genetic screens for mutations that affected formal aspects of this behavior. This led to a number of important discoveries, such as the fact that light is required for the developmental expression of functional circadian systems in embryonic zebrafish, as well as the characterization of a number of mutations in genes that affected circadian oscillators (some of this later work in collaboration with Dan Wells). A particularly important publication in PNAS in 2006 described a luciferase reporter system for circadian oscillators in zebrafish that allowed independent analyses of circadian outputs from multiple tissues simultaneously, as well as the development of a number of cell lines for analyses of circadian oscillators. Most recently, in collaboration with Dr. Greg Roman, the Cahill group reported effects of melatonin on nighttime memory formation in zebrafish. This article appeared in Science in 2007. Greg had almost continual federal funding for his research at UH from the time he arrived until shortly before his death. He also served on a large number of federal review panels, and did editorial work for essentially every prestigious journal in his field. He was much in demand as a speaker at meetings around the world and was generally regarded as one of the best of an outstanding young group of chronobiologists. Greg was an outstanding teacher and a number of students earned graduate degrees and did postdoctoral work under his supervision. Greg’s efforts earned a Research Excellence Award from the University of Houston in 1998.

Greg was an avid outdoorsman, and had a particular love for river rafting and exploring mountain wilderness. Within the department he is remembered by all of us for his easy smile, his keen insight, his deep and unselfish caring for all students, his collegiality, and his willingness to help people in many different ways. There are many of us whose grant applications and research projects were successful in large measure because of Greg’s helpful suggestions, and there are many students whose lives he touched in a meaningful way. Greg will be greatly missed by everybody in the UH community, and by biological clocks researchers all over the world.