2026-03-26 ゲーテ大学
＜関連情報＞
- https://aktuelles.uni-frankfurt.de/english/evolution-in-fast-forward-how-thale-cress-adapts-or-goes-extinct/
- https://www.science.org/doi/10.1126/science.adz0777
シロイヌナズナの同期屋外進化実験における急速な適応と絶滅 Rapid adaptation and extinction in synchronized outdoor evolution experiments of Arabidopsis
Xing Wu, Tatiana Bellagio, Yunru Peng, Lucas Czech, […] , and Moises Exposito-Alonso
Science Published:26 Mar 2026
DOI:https://doi.org/10.1126/science.adz0777
Editor’s summary
For organisms with generation times longer than those in yeast or bacteria, testing the repeatability of evolution in differing environmental conditions takes a great deal of time and resources. Wu et al. enlisted the help of citizen scientists in Europe, the Levant, and the US to grow 12 replicates of the same array of 231 Arabidopsis thaliana accessions to see how the populations evolved over 5 years. Over the 30 locations where the plants grew successfully, the authors found that frequency shifts largely replicated within gardens, and that these shifts tended to be similar between locations with similar environments. This large undertaking gives insight into how these plants may evolve in response to future changing pressures such as climate change. —Corinne Simonti
Structured Abstract
INTRODUCTION
Contemporary evolution in natural environments is being documented in many plant and animal species. However, an integrative understanding of the dynamics of rapid adaptation to different climates—the tempo, genetic architecture, predictability, and population feedbacks—remains unclear for most species. The gold standard to experimentally study the dynamics of evolution has been represented by microbial long-term laboratory experiments combined with genome resequencing, but such experiments remain challenging in multicellular macroorganisms, especially in ecologically realistic environments.
RATIONALE
We studied the evolutionary and population dynamics of rapid adaptation in different climates with an internationally synchronized outdoor evolution experiment using the annual plant Arabidopsis thaliana. After coordinated planting of an equal mixture of 231 A. thaliana accessions, 12 replicates were established at 30 sites across Western Europe, the Mediterranean and Levant, and the United States for up to 5 years. Experimental sites spanned contrasting climates—from urban European environments to the likely edge of the species’ niche, the Negev desert. Combining high-coverage sequencing of 231 founder accessions with pooled whole-genome sequencing of more than 2500 samples of surviving adults comprising more than 70,000 tissue samples in the first 3 years, we characterized the dynamics of evolution in real time across climates.
RESULTS
Standing genetic variants changed in frequency rapidly across experiments, with repeatable trends among populations within similar climates but diverging trends across contrasting climates. Allele frequency shifts significantly exceeded neutral expectations. We reason that much of such shifts may be attributed to environmental natural selection, as we observed significantly synchronized (both increasing and decreasing) trends in allele frequency shifts across independent population replicates, both within one garden and in different gardens with similar climates. Such repeatability was observed in 24 of 30 gardens. Accessions from climatically matching origins increased in frequency, following patterns of past local adaptation with the strongest signals for annual mean temperature. Yet for accessions from warm regions, where we found strong local adaptation signals, we detected evidence for a recent adaptation lag; that is, they had the highest fitness when transplanted to gardens ~1.5°C colder than their home sites.
Experimental evolution genome-environment associations (eGEA) identified genomic regions that overly diverge across climates, including both known adaptive loci, such as a florigen-encoding gene, as well as genes potentially involved in thermal response, such as CAM5. This gene, found in a region with low linkage disequilibrium, represented one of the most pronounced allele frequency shifts, which is best explained by selection coefficients reaching –46 to +60% from cold to warm gardens, respectively. The overall genetic architecture was highly polygenic, but allele trajectories were partially predictable using genomic offset models.
CONCLUSION
Despite evidence for rapid evolution across several climates, evolutionary trends were unpredictable in a fraction of gardens and experimental replicates. In the warmest environments, which are expected to become more prevalent with global climate change, we found that early-generation evolutionary repeatability separated persisting experimental populations from those that suffered extinction, suggesting eco-evolutionary tipping points where extreme selection overwhelms adaptive potential. Although rapid climate adaptation is possible through standing genetic variation, understanding which environmental, genetic, or species-specific conditions dictate evolutionary limits will be critical for predicting biodiversity responses to climate change.
Rapid evolutionary adaptation across climates in A. thaliana.
(Top left) A coordinated distributed evolution experiment establishing outdoor gardens with a mix of A. thaliana natural populations. (Top right) Populations were seeded outdoors with an equal genotype mixture, exposed to natural local climatic conditions, and whole-genome sequenced over years. (Middle center) Example allele with divergent trend along an annual temperature gradient. (Bottom left) Genome scan pointing to an example allele. (Bottom center) Estimated environment niche of the original source population either carrying or not carrying an adaptive allele. (Bottom right) Survival of replicated experimental populations after years, explained by early repeatable evolutionary trends in warm locations.
Abstract
Climate change forces species to adapt rapidly to avoid extinction. To directly observe rapid adaptation and extinction, we conducted synchronized evolution experiments with Arabidopsis thaliana in 30 locations across Western Europe, the Mediterranean, the Levant, and North America. Whole-genome pooled sequencing of ~70,000 surviving plants revealed repeatable allele frequency shifts in similar climates but divergent shifts across contrasting ones, indicating evolutionary adaptation. We identified genetic variants linked to climate adaptation, including genes involved in processes ranging from thermal-stress sensing to spring-flowering timing. Evolutionary trends were often predictable, but variable, across environments. In warmer climates, evolutionary predictability correlated with population survival over 5 years, whereas erratic changes preceded extinction. These results show that rapid climate adaptation is possible, but understanding its limits will be crucial for biodiversity forecasting.
