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Meeting Abstract
It has been recognized for decades that animals sense light using photoreceptors besides those that are devoted strictly to vision. However, the nature of these receptors, their molecular components, their physiological responses, and their biological functions were long obscure. Only recently have researchers begun to learn how critical these nonvisual or very simple visual responses are to organismal function; and new approaches, including the explosion of research incorporating high-throughput molecular genetic techniques, have led to a revolution in our understanding of the evolution, anatomical distribution, and function of nonvisual photoreception in a variety of evolutionarily distinct animals. Historically, these types of receptors have been described primarily among invertebrates, although they were recognized to be present in fishes, reptiles, and birds. Their presence in mammals was completely unsuspected until the end of the 20th century. In this symposium, we bring together specialists from throughout the field to review the current state of knowledge regarding extraocular, nonvisual, and simple photoreceptors in a large diversity of organisms ranging from protists to higher vertebrates and invertebrates.