The contribution of introgression to convergent floral adaptation in Penstemon

Convergence is the repeated evolution of the same traits in different species. Understanding how and when unrelated organisms have converged in response to their environments provides important biological insight. It is often assumed that mutations drive such evolution.

Yet, beneficial genes may also be transferred between species through hybridization speeding up evolution. This research examines evolution of flowers that are attractive to hummingbird pollinators. These attractive flowers have evolved approximately 20 times in one group of plants, even though it requires altering several floral traits.

This project will clarify the relationship of species within that group of plants and determine the likely genes involved in the floral evolution. It will also study natural populations to determine the ecological consequences of species hybridization. In the process of this research a diverse group of graduate and undergraduate students will be trained in genetics and botany providing an increased understanding of the practice of science in society.

This project is jointly funded by the Evolutionary Processes Program, the Established Program to Stimulate Competitive Research (EPSCoR), and the Systematics and Biodiversity Science Program.

This research examines genetic variation causing floral adaptation in the North American plant genus Penstemon. It uses genome-wide data that is analyzed in a phylogenetic framework. This approach will enable the researchers to determine if hummingbird-adapted flowers arise through introgression after hybridization.

The analysis will focus on regions of the genome known to affect floral traits. Complete genomes of members of the genus will be collected. Associations of genetic variation, trait variation, and reproductive success of individual plants in a naturally occurring hybrid populations will then be determined.

This will allow the researchers to examine the consequences of natural hybridization and test predictions that hybridization may contribute to convergent origins of hummingbird-adapted flowers. Together these investigations address whether and how hybridization leads to convergent adaptive evolution of a complex trait.

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.