This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2025. The fellowship supports research and training of the fellow that will contribute to biology in innovative ways. This research seeks to understand the “cost of complexity,” how multiple functions of a gene restrict the gene’s ability to adapt to changing environmental conditions. This project uses rhodopsins from cyanobacteria (bacteria that harness energy from sunlight) as models of multifunctional genes. Rhodopsin proteins absorb specific colors of light and use the associated energy to pump protons out of the cell as a part of their energy harvesting mechanism. This research hypothesizes that rhodopsins that are forced to maintain their proton-pumping function will be less capable to adapt to absorbing alternative colors of light than rhodopsins that are allowed to lose proton-pumping functionality. Better understanding of this evolutionary principle will bolster scientists’ ability to predict how species will adapt to changing environments. Furthermore, the color-adapted rhodopsins produced in this project will enhance cyanobacteria-based biofuel production by capturing a broader range of light. The fellow will participate in community science outreach to help the public understand the impact of scientific research on their lives and mentor undergraduate researchers to help train the next generation of scientists. To simulate evolution on a laboratory timescale, mutants of Gloeobacter rhod