Skip to main content
Dryad

Data from: Natural selection drives emergent genetic homogeneity in a century-scale experiment with barley

Koenig, Daniel1; Landis, Jacob1; Guercio, Angelica1; Brown, Keely1; Fiscus, Chris1; Morrell, Peter2

Published Jul 11, 2024 on Dryad. https://doi.org/10.5061/dryad.z34tmpgm8

Data files

Jul 11, 2024 version files 3.30 GB

Abstract

Direct observation is central to our understanding of the process of adaptation, but evolution is rarely documented in a large, multicellular organism for more than a few generations. Here, we observe genetic and phenotypic evolution across a century-scale competition experiment, barley composite cross II (CCII). CCII was founded in 1929 with tens of thousands of unique genotypes and has been adapted to local conditions in Davis, CA, USA for 58 generations. We find that natural selection has massively reduced genetic diversity leading to a single clonal lineage constituting most of the population by generation F50. Selection favored alleles originating from similar climates to that of Davis, and targeted genes regulating reproductive development, including some of the most well-characterized barley diversification loci, Vrs1, HvCEN, and Ppd-H1. We chronicle the dynamic evolution of reproductive timing in the population and uncover how parallel molecular pathways are targeted by stabilizing selection to optimize this trait. Our findings point to selection as the predominant force shaping genomic variation in one of the world’s oldest ongoing biological experiments.