IntBIO COLLABORATIVE RESEARCH: Deep Time, Development, and Design: Evolution of shark skin teeth from genotype to phenotype to prototype.

The skin of sharks is unique among vertebrate animals because it contains tooth-like scales, called dermal denticles, that create a hard external armor. These tooth-like denticles evolved over millions of years and equip the shark with hydrodynamic skin that reduces the cost of moving through the water. This advanced streamlining is currently a subject of great interest, with many industries attempting to take advantage of shark skin technology to create more efficient swimming designs. This project aims to provide a complete integrated understanding of shark denticles: how they form in embryonic sharks, how denticle shape has changed over years of evolution, and which denticle types are the best for drag-reduction and further design advances. This knowledge will enable better use of shark skin technology to make advanced design solutions that help to make a better and more environmentally friendly world. For example, one possible use of shark skin technology is the development of surface structures on airplanes or boats to reduce drag during movement and decrease fuel emissions. In addition to its scientific impact, this project has impact on the STEM workforce by supporting principal investigators and trainees across a wide range of career stages and by providing a unique, much-needed accessible research training program for undergraduates with disabilities in interdisciplinary research. The shape and pattern of shark skin teeth, or denticles, has been refined over millions of years of evolution for functional improvements in aquatic locomotion. This project addresses the evolutionary and developmental trajectories that have led to a vast diversity of shark skin denticle types with the goals of determining why sharks have different shaped denticles among and within species and what functional advantages these different denticle shapes might offer these animals. From an integrated developmental, genetic, and evolutionary framework, the project will investigate how denticles develop and what factors lead to changes in shape. The approach will include studies of embryonic denticle development from the level of single cell transcriptomics to phenotypes and function to learn what key genes are essential to the production of various denticle shapes in a range of shark species and how these shapes are achieved via developmental innovation. Goals include understanding what shapes are most efficient for drag-reduction in both modern and extinct species to enable modeling and testing of new engineering designs to reduce drag in air- and water-borne vehicles and devices. Combining 3D printing with engineering methods, new shark-inspired surface structures will be used to create a shift in design solutions for a changing and more environmentally friendly world. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.