Deconstructing avian cone photoreceptors: a system of self-organizing optical microdevices

Avian cone photoreceptors possess an astonishingly rich repertoire of evolutionary adaptations for color vision, yet the function of most of these adaptations remains obscure. The goal of this proposal is to take a highly interdisciplinary approach to dissect the structure, function and genetic basis of the optical adaptations of avian cones. We will elucidate the principles governing this system via a combination of molecular genetics/genomics, optical physics, computer modeling and vision-guided behavioral assays using the chicken as our model. Aim #1 will use genetic knockdown of cone opsins coupled with assays of visual function in modified animals to test the hypothesis that color and luminance information are channeled through single and double cones, respectively. Aim #2 will dissect the optical function of oil droplets, carotenoid-containing organelles unique to cones. We will discover genes required for oil droplet formation/pigmentation and will genetically engineer animals with modified droplets for optical modeling and behavioral analysis. Lastly, Aim #3 will elucidate the spatial properties of the cone mosaics via molecular analysis, modeling and behavioral assays.