Intraspecific functional variation, the functional variation of a trait within a species, is critical for adaptation to rapidly changing environments. Ciscoes and Deepwater Sculpin are two lineages of North American deep-dwelling fish that recently, less than 15,000 years ago, began to inhabit postglacial lakes differing in water depth, clarity, and composition. As such, they make ideal species for studying intraspecific functional variation and gleam insight into rapid visual evolution. These species are also of cultural, commercial, and nutritional importance to Indigenous communities but have faced significant declines due to environmental perturbations and overfishing, among other factors. Understanding the ecological and genetic factors involved in these declines is essential for their conservation.
A metabarcoding approach to map functionally relevant rhodopsin variants.
Alex Van Nynatten and colleagues have identified depth-related variation in the dim-light visual pigment rhodopsin that evolved convergently in ciscoes and deepwater sculpins. In vitro characterization of the convergent alleles revealed blue shifts compared with more widely distributed alleles, closely mirroring the visual aquatic environment of the specific fish they were collected from. In collaboration with the Saugeen Ojibway Nation, Van Nynatten et al. have also developed and tested a metabarcoding approach to efficiently and accurately map the functionally relevant rhodopsin variation. These initiatives are highly informative, outlining a framework to apply the study of adaptive molecular evolution to conservation efforts.