Postdoctoral Fellowship: PRFB: Estimating the role of floral isolation in complex trait evolution and plant speciation

This action funds an NSF Plant Genome Postdoctoral Research Fellowship in Biology for FY 2024. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The title of the research and training plan for this fellowship to Aidan Short is "Estimating the role of floral isolation in complex trait evolution and plant speciation".

The host institution for the fellowship is the University of South Carolina and the sponsoring scientists are Dr. Carolyn Wessinger and Dr. John Kelly.

Floral isolation, or the evolution of combinations of floral traits that match the preferences of distinct pollinators, is hypothesized to promote the diversification of flowering plants due to the reduction of interbreeding between closely related plant species. In this research, the ability of floral isolation to contribute to plant speciation will be tested by first, estimating the evolutionary history of floral trait genes that contribute to divergent pollinator adaptation between two pairs of hybridizing plant species, and then, using theoretical modeling to estimate how floral isolation impacts levels of genetic divergence at floral trait genes and across the genome.

The data and insights generated from this research will have implications for existing theories in evolutionary biology, agriculture, and conservation about the importance of pollinator adaptation and plant-animal interactions to the diversification of plant species. To promote diversity in the sciences, a chapter of the Alliance for Diversity in Science and Engineering will be established at the host institution.

This chapter will be committed to inviting diverse speakers from various scientific fields to give talks at the host institution and neighboring K-12 public schools. Furthermore, to encourage students of various age groups and backgrounds to think scientifically and picture themselves as scientists, scientific outreach events will be organized at local K-12 schools.

This research will integrate empirical population genomic analyses and theoretical modelling and simulations to understand how divergent adaptation contributes to the maintenance of complex traits and promotes plant speciation. These goals will be pursued in three primary Aims. In Aim 1, genomic data will be used to estimate the strength and history of selection on floral trait loci between a pair of hybridizing plant species that display evidence of divergent pollinator adaptation.

In Aim 2, genome wide variation in gene flow between two pairs of hybridizing plant species will be identified, and then the relationship between levels of gene flow and the strength of selection at floral trait loci will be estimated. In Aim 3, theoretical modelling will be used to estimate how variation in the strength of floral isolation (assortative mating and hybrid fitness) contributes to genome wide levels of divergence between a pair of hybridizing species.

This research will generate novel molecular data (population-level whole-genome resequencing data) for pairs of hybridizing taxa from the genus Penstemon that display evidence of divergent floral adaptation and will integrate empirical and theoretical population genomics to identify how floral diversification has contributed to the diversification of angiosperms. Sequencing data and associated metadata will be deposited in the NCBI sequence read archive.

Code for the performance of simulations and the analysis of genomic data will be uploaded to GitHub.

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.