The genomic and ecological basis of rapid change in a functionally significant trait: osteoderm evolution in a girdled lizard.

Osteoderms are bony elements that are expressed in the skin of a few disparate groups of tetrapods (i.e. in crocodiles, turtles, armadillos, and some lizard and frog species) – but not in other taxa. In humans, osteoderms are frequent complications of injury and in a few rare inherited disorders. Osteoderms spark interest because they are ecologically relevant (they are likely to function in body protection, thermoregulation and water budget maintenance, in mineral storage) but at the same time exhibit an unusually binary distribution (i.e., they are expressed completely, or not at all). The latter element facilitates research into the genomic substrate of the trait. One species of cordylid lizard, Hemicordylus capensis, uniquely displays intraspecific variation in osteoderms: the trait has evolved repeatedly and therefore is present in some populations, but not in others. The species thus offers exceptional opportunities for learning how, why and when this remarkable trait evolves. With this project, we aim to resolve those issues through a thoroughly integrated approach combining state-of-the-art genomic, functional morphological and ecological techniques. We will also explore if we can extrapolate the findings on this study system to other taxa that (occasionally) express osteoderms, including humans. The project will allow a rare complete view of the evolution of an ecologically relevant phenotypic characteristic with a remarkably discontinuous variation and an unusually disparate taxonomic distribution.

Keywords:GENOMICS, BONE STRUCTURE, ECOLOGICAL MORPHOLOGY, ADAPTATION

Disciplines:Animal ecology, Animal morphology, anatomy and physiology, Vertebrate biology, Analysis of next-generation sequence data, Bioinformatics of disease, Computational evolutionary biology, comparative genomics and population genomics, Ecophysiology and ecomorphology, Biology of adaptation, Evolutionary developmental biology, Phylogeny and comparative analysis