Biologists have long grappled with the challenge of predicting how quickly plants can evolve to cope with the accelerating impacts of climate change. Traditional research methods, often isolated and limited in scope, have done little to keep pace with the urgent need to understand species’ responses. However, a groundbreaking experiment led by Moisés (Moi) Expósito-Alonso aims to change this by uniting scientists in a massive, synchronized study across diverse climate zones.
Expósito-Alonso and his team established a collaborative network to plant the laboratory staple Arabidopsis thaliana across 30 distinct climate zones in Western Europe, the Mediterranean, the Middle East, and North America. Over five years, these plants were left to evolve naturally, with researchers observing how they adapted to varied environmental stresses, from the cold Alps to the arid Negev Desert.
Understanding the speed and genetic shifts of evolution is crucial for developing models that predict which species are most at risk due to environmental changes, according to Expósito-Alonso, an assistant professor at UC Berkeley. “All of those species that are under protection, for example in natural parks, will still suffer from changing local climates,” he noted, emphasizing the importance of such data in crafting strategies for conservation.
White-flowering Arabidopsis growing in sand at a beach near the Baltic sea. The plant, a member of the mustard family, grows in a broad range of climates, from alpine to desert, and is commonly used in genetic experiments in the lab.
Moisés Expósito-Alonso/UC Berkeley
The research, which analyzed three years of genomic data from 360 experiments, revealed that many plant populations adapted genetically to their new environments. However, in extreme heat conditions, some populations showed no early evolution signs and eventually faced extinction. “Our big questions were, ‘At what speed does evolution go?’ and ‘When will it not go?’” Expósito-Alonso explained, highlighting the varied tempo of evolution.
“Our big questions were, ‘At what speed does evolution go?’ and ‘When will it not go?’” Expósito-Alonso said. “What we could show is that this tempo, if given enough genetic diversity, can be three, four, five years. We can directly see for the first time how certain DNA variants — adaptive variants — take over in certain populations as evolution happens.”
Yet, the study found that not all groups adapted sufficiently to survive, particularly in the hottest climates. Expósito-Alonso commented, “This reveals that, while rapid adaptation to climate change is possible, extreme heat limits populations to small sizes, which can push populations past an evolutionary breaking point toward extinction.”
The study, published in Science and conducted in partnership with institutions like Goethe University and the University of Montpelier, ran from 2017 to 2022. The project explored not only the speed of adaptation but also the genetic mutations that enable it. Each plot contained a diverse gene pool, ensuring that some plants possessed the rare genetic traits necessary for resilience.
Plots of Arabidopsis thaliana partially covered by snow in Brixen im Thale, a town in the Kitzbühel Alps of western Austria. This was one of 30 research sites around Europe, the Middle East and the U.S. in which biologists planted 12 separate plots to study genetic evolution under the influence of climate change.
Genomics of rapid Evolution to Novel Environment (GrENE) network consortium
By sequencing the genomes of over 70,000 surviving plants, researchers identified millions of genetic changes that indicated adaptation efforts. These alterations varied by climate but were consistent across similar environments, showcasing the repeatability of evolutionary responses. “What we’re most likely seeing is adaptation through pre-existing genetic variation that gets re-used in different ways,” said Xing Wu, a postdoctoral fellow and first author of the paper.
While some genetic changes met expectations, the speed of allele frequency changes surprised researchers. Not all plots evolved; some saw extinction due to random genetic shifts. “There were some climates where either there were no shifts, so the frequency of those genetic variants was the same, or there were shifts, but they were not repeatable in the different independent replicates,” said Tatiana Bellagio, co-first author of the paper.
Continued analysis aims to improve predictions of species’ survival under climate change. The research points to the potential of genomic forecasting, as noted by collaborator Stephen Keller: “This study does just that — observes evolution in real-time in response to natural selection under novel climates, confirming the potential that genomic forecasting has to help us understand the fate of populations under climate change.”
Supported by various organizations, including the National Institutes of Health and the U.S. Department of Energy, Expósito-Alonso’s work continues with additional experiments at UC Berkeley. His long-term goal is to observe rapid evolution in natural plant populations, capturing genetic changes triggered by environmental factors like drought or wildfire.
Moisés Expósito-Alonso with the two lead authors of the new study, Tatiana Bellagio and Xing Wu (holding a tray of Arabidopsis seedlings).
Moisés Expósito-Alonso/UC Berkeley
Original Story at www.uvm.edu