SRA

Colour in nature has many functions, including pollinating flowers, mating displays and camouflage. Colour within the tree of life can be created by multiple mechanisms. Pigmentation is the most familiar, where molecules absorb specific wavelengths of light. However, structural colour is also widespread, most familiar from the vividly coloured feathers of the peacock, and uses a completely different way of generating colour. Structural colour is based around light interference, the interaction of light with precisely ordered biological structures. Surprisingly, very little is known on what genes are required to create colour and how SC has evolved. Bacteria, including some Flavobacteriia and some Proteobacteria, can organize to create vividly coloured, iridescent colonies which indicates SC. As a relatively simple organism, bacteria were chosen to understand the genomics of structural colour. By isolating and sequencing the genomes of bacteria showing SC, and comparing with bacteria in which this property is absent, it has been possible to understand which genes are important for this phenotype. Comparative genomics has been used to create a computational tool to predict which bacteria can organize to create structural colour and where to find them. We found that many species of bacteria not previously thought to be structurally coloured could potentially show this phenomenon and that SC is widely distributed in aerobic environments and apparently rare when associated with macroscopic organisms with the exception of algae. This is the first comparative genomics approach to SC in any organism.