The Genetics and Trade-Offs of Iridescent Structural Colour

Structural colour is one of the three main forms of coloration in animals, often manifested as iridescence. Iridescence is a phenomenon that produces a vivid metallic colouring depending on viewing angle. Layered or otherwise periodic arrangements in feathers, cuticle and scales cause these striking interference effects.

Structural colour plays a role in a wide range of evolutionary and ecological processes, ranging from mate choice, predator avoidance, sexual selection, and signalling in general. To fully understand these functions it is necessary to dissect their genetic basis.

However, whilst the genetics of pigment-based colour are well known, little is known about the developmental basis and the gene-regulatory mechanisms underlying structural colour.

Structural colour is far more complex than its pigment-based counter-part, and involves the organization of cells in layers to form periodic keratin complexes and multilayers.

Due to this complexity, we hereby propose a multidisciplinary approach in which we will combine high-resolution physical measurements with genetics, organogenesis and studies of gene control at a single cell resolution to identify how such complex physical properties are achieved at the organ level.

This knowledge will then be integrated with ethological and life history assays in a natural population of feral chickens to identify the evolutionary implications and genetic trade-offs that result from one of the main forms of coloration.