NSF PRFB FY22: Disentangling early stages of diversification: The roles of biotic and abiotic environment and evolutionary history on floral phenotypes in species complexes

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2022, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. Understanding how life on earth evolves requires understanding the processes that give rise to this diversity of life.

The process generating new species (called speciation) is a continuous, ongoing process, and questions remain about its early stages. Early stages of speciation can be well understood by studying what are called species complexes, which are groups of species that are closely related, and often exhibit distinct but overlapping variation in traits and likely continue to interbreed.

Studying species complexes allows this research to zoom in on early stages of speciation to examine how an organism’s local environment shapes the evolution of both its physical traits (phenotype) and its genetic makeup (genotype). By doing so, this research will contribute to our understanding of how the diversity of life on earth has arisen and how it continues to evolve.

This work will help inform efforts to support and protect biodiversity and will encourage the next generation of scientists through outreach and education.

This research will characterize incipient divergence among flowering plants by examining floral trait variation in the recently radiating genus Castilleja (the paintbrushes), focusing on the C. sessiliflora and C. pilosa species complexes. The research will explore patterns of phenotypic and genomic divergence in contrasting environments, resulting in a predictive model of species delimitation in young lineages.

This project will employ ddRad-sequencing to identify evolutionary units and spatio-temporal patterns of divergence in these groups. Next, the fellow will explore processes potentially driving these patterns by using structural equation modeling to compare how different biotic and abiotic environmental factors contribute to floral variation. She will then identify regions of genomic variation associated with floral variation, assessing them for signatures of selection and divergence, which will shed light on specific regions of the genome important in early stages of speciation.

Overall, this project will connect genomic and phenotypic variation to understand how interactions with the environment drive incipient speciation. Additionally, the fellow will contribute to outreach and mentoring, through summer research programs and the generation of STEM teaching materials, which will be available in English and Spanish and will be distributed from coast to coast in partnership with Maryland 4H and California Academy of Sciences, thus helping to broaden participation and inclusion in STEM.

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.