DISSERTATION RESEARCH: Development and Evolution of Iridescent Colors in Feathers

University Of Akron, Akron OH

Investigators

Abstract

How do complex structures originate and diversify through evolutionary time? Our research will address this question using the iridescent colors of feathers, which are the brightest and most diverse found in nature. These colors are produced by optical interference, similar to that producing rainbow colors in soap bubbles, from biological tissue (keratin and melanin-containing organelles called melanosomes) that is precisely organized at the nanometer scale. Because the colors produced result from the size and shape of these organized structures, minute changes can produce dramatically different colors, making it an ideal system for the study of the evolution of complex morphologies. We propose to investigate two crucial aspects of this system: first, how does this meticulous organization take place? We have evidence that these structures self-organize as a consequence of physicochemical interactions during feather development when the concentrations of keratin and melanin are high. We will now test this hypothesis by quantifying the expression of genes regulating these processes during feather development. Second, how can these structures be modified to produce novel colors? We will investigate this question in African Starlings, a group of birds with several modifications to their melanosomes that allow them to interact with light in even more complex ways. Using modern comparative methods, we will investigate the role of these innovations in the diversification of color and the patterns of speciation within this group. By studying how these complex structures originate as a result of small genetic changes, and how they can then be modified to produce novel colors, our research will provide new insights on the evolution of innovations that shape the diversity of life, and may provide inspiration for new self-assembling nanostructures with applications in fiber optics and coatings. Our project will rely on international and multi-institutional collaboration, which will continue to involve undergraduates and students from under-represented groups in the US and Latin America, who will be engaged in all stages of this cross-disciplinary study.