Photobiological Origins of the Field of Genomic Maintenance.

Although sunlight is essential for life on earth, the ultraviolet (UV) wavelengths in its spectrum constitute a major threat to life. Various cellular responses have evolved to deal with the damage inflicted in DNA by UV, and the study of these responses in model systems has spawned the burgeoning field of DNA repair. Although we now know of many types of deleterious alterations in DNA, the approaches for studying them and the early mechanistic insights have come in large part from pioneering research on the processing of UV-induced bipyrimidine photoproducts in bacteria. It is also notable that UV was one of the first DNA damaging agents for which exposure was directly linked to cancer; the sun-sensitive syndrome, xeroderma pigmentosum, was the first example of a cancer-prone hereditary disease involving a defect in DNA repair. We provide a short history of advances in the broad field of genomic maintenance as they have emerged from research in photochemistry and photobiology.