Abstract Detail

Population Genetics/Genomics

Ruffley, Megan [1], Leventhal, Laura [2], Exposito-Alonso, Moi [2].

Mapping genetic constraints of drought adaptation strategies in the eco-evolutionary model system, Arabidopsis.

Genetic correlations between traits are thought to be a main constraint to adaptation, as multiple advantageous trait strategies cannot evolve simultaneously. However, comprehensive studies of how genetic correlations persist in natural populations and their ecological relevance when subject to climate-driven natural selection are rare. Through common garden experiments with hundreds of Arabidopsis thaliana ecotypes, Exposito-Alonso et al. (2019) showed pervasive antagonistic selection on alleles across high and low rainfall environments. Integrating published ecologically-relevant traits for overlapping ecotypes, we quantify natural selection over phenotypic selection under these extreme rainfall environments. We find evidence of a selection conflict between two adaptive strategies, so-called drought escape and drought avoidance. Genome-wide association approaches allowed us to confirm these drought adaptation strategies are indeed genetically correlated and that hotspots of genetic correlation across these phenotypes map to corresponding regions of the genome that are under antagonistic selection. Using future climate predictions, we see the trajectory of the drought strategies in phenotypic space continue to diverge in their extreme environments. However, given the genetic constraint amongst these strategies, the phenotypic evolution predicted by the changing climate is impossible. These results indicate that natural populations of A. thaliana experience a genetic constraint to drought adaptation and importantly, this must be accounted for when making predictions about how species will adapt to a changing climate.

1 - Carnegie Institution for Science, Department of Plant Biology, 260 Panama St., Stanford, Ca, 94305, USA
2 - Carnegie Institution for Science, 260 Panama St., Stanford, Ca, 94305, United States

genetic constraint
complex traits

Presentation Type: Oral Paper
Number: PGG2001
Abstract ID:93
Candidate for Awards:Margaret Menzel Award

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