NSF Postdoctoral Fellowship in Biology FY 2012

Toomey Matthew B, Tempe AZ

Investigators

Abstract

Title: The optics of avian cone oil droplets The brilliantly colored oil droplets within the cone photoreceptors of birds have fascinated biologists since the dawn of microscopy, yet a conclusive understanding of their function has remained elusive. Located between the inner and outer segments, oil droplets are perfectly situated to filter and focus the light onto the photoreceptive visual pigment. Thus avian cone oil droplets may function as sophisticated photonic devices: (1) enhancing behavioral color discrimination by acting as long-pass spectral filters to modify the spectrum of light reaching the outer segment and (2) as focusing elements with a self-assembled liquid crystalline order optimized for light transmission within each different cone type. To test these hypotheses, the project will span the intersection of biology and physics combining molecular genetic manipulations of oil droplet pigmentation (via RNA interference) with behavioral tests of color vision, and advanced optical measurements (digital holographic microscopy) of the oil droplet molecular structure and light transmission. This project has broad implications because colorful cone oil droplets are an evolutionarily ancient adaptation to bright terrestrial environments shared by a diversity of animals. Understanding of the optical and behavioral function cone oil droplets has the potential to reveal previously unknown visual capabilities and adaptive mechanisms. The training goals are to develop an understanding in, and technical competency with, molecular biological and optical physics approaches that will allow the fellow to build a research program at the intersection of biology, chemistry, and physics. Additionally, the fellow will receiving training in the communication of science to various audiences through written materials and formal and informal presentations.