The dark pigment, melanin, is thought to provide protection of tissue from damage from harmful effects of sunlight exposure. However, melanin also is found in the inner ear, and in the embryonic eye. In certain genetic strains with reduced melanin, called hypopigmented, there are specific defects of auditory or visual properties, where the severity seems to correlate with the extent of melanin reduction and not with mutations in particular genes. This project uses a multi-disciplinary approach of anatomy, physiology, behavior and classical genetics to determine how reduced melanin in the eye is related to the elevation of dark-adapted thresholds for vision, and to determine the location of the defect within the retina of the eye. A novel hypothesis will be tested, to see whether melanin may be acting as a buffer for calcium around the photoreceptor cells. In addition to the impact on visual neuroscience, the results could have impact on our understanding the basic role that this ubiquitous pigment has in environmental adaptations in other systems and animals.
