Evolution and Development of Color Vision in Vertebrates

Deborah Stenkamp

Department of Biological Sciences

Presented with support of the Provost’s Office and University Honors Program

Abstract

Color vision in vertebrates requires the existence of multiple types of cone photoreceptors in the retina, each of which has a different sensitivity to the visual spectrum. Spectral sensitivities are conferred by the visual pigment present within cone photoreceptors. In primates and in fishes, the diversity of cone photoreceptor types has been increased through evolutionarily recent duplications of visual pigment genes.

In humans, the tandemly duplicated “red pigment” and “green pigment” genes on the X chromosome underlie trichromatic color vision. Defects in these genes result in color blindness and X-linked retinal degenerations. Treatments for some of these disorders would be facilitated by further knowledge of how differential gene expression — the production of a red pigment vs. a green pigment — is regulated in developing cone photoreceptors.

Our research group has recently uncovered evidence that the expression of pigments from a similar tandemly replicated red pigment gene array in zebrafish can be regulated by the developmental signaling molecules, retinoic acid, and thyroid hormone. Our findings suggest that tandemly duplicated cone pigment genes may be amenable to therapeutic manipulation.

Biography

Deborah Stenkamp is a professor of Biological Sciences and the current College of Science Malcolm and Carol Renfrew faculty fellow. She has maintained an NIH-supported research program in development and regeneration of the visual system, at the University of Idaho, since 1997. She earned a bachelor’s degree in biology from Whitman College and a doctorate from Johns Hopkins Medical Institutions.