Periodic Reporting for period 2 - EYESPOT (The Genetic, Cellular, and Photonic Mechanisms of Avian Structural Colouration)
Période du rapport: 2023-04-01 au 2024-09-30
Birds are a group known for their wide variety of beautiful colors, from discreet browns and blacks in sparrows and partridges, to vibrant reds and yellows in canaries and parrots. However, shades of blue, and even iridescence, result from the optical and physical effects of light refraction in melanin (brown and black), giving rise to what is known as structural color. Depending on the complexity of the melanin organization, the structural color can vary from the strong blues of kingfishers to the most iridescence of hummingbirds. The domestication of peacocks has led to the appearance of more than a dozen color variants. By analyzing the genomes of these mutants, this project aimed to integrate molecular, optical and physical processes to explain the extraordinary variation in structural color and iridescence in birds. We found that, with small changes to melanin production, in the melanosome biogenesis and maturation, or in their transport to the feather, it is possible to vary the way in which these nanostructures self-organize during feather keratinization, and thus gain, lose or vary the hue and intensity of structural color. With this knowledge we can (bio)mimic nature's technology to produce colorful—and even iridescent—synthetic materials that do not lose intensity through exposure, unlike pigment colors. In this proposal, we intend to employ genomic, transcriptomic, and epigenomic approaches in several wild and domestic bird species to provide a general framework for understanding structural coloration in a wide range of species, thereby greatly expanding our understanding of this fascinating biological phenomenon.
We have sampled over 400 peafowl mutants and generated over 300 whole genomes, and over 40 RNAseq datasets. We have developed a protocol for dissociation of feather follicles and performed single-cell transcriptomic analysis. We have organized multiple meetings in the scope of the project with international collaborators, organized outreach sessions and written two manuscripts.
We have mapped the causal mutation of multiple peafowl mutants and characterized the phenotypes of such mutants at the biochemical and nanostructural level. We expect to develop a mathematical model to predict structural color variation and, from there, produce synthetic materials that mimic the nanostructural structure, and thus produce the colors seen in biological tissues. Our research will contribute to a deeper understanding of the molecular underpinnings of avian structural colors, an area currently trailing behind pigmentary color mechanisms in terms of comprehension.