Moisés Expósito-Alonso began studying genetics because he was interested in “how a plant decides what to do without a brain.” Then, as an intern at Spain’s Duana National Park during undergraduate studies, he learned that plant decisions are genetically controlled. “You can tell a lot about an organism based on its genome. That was the idea that intrigued me and that’s how I got into genetics,” says Expósito-Alonso, now an assistant professor of integrative biology at the University of California, Berkeley, and a Freeman Herbowski Scholar at the Howard Hughes Medical Institute. Career Medal.
Before he began his PhD research at the Max Planck Institute for Biology in Tübingen, Expósito-Alonso already knew what he wanted to work on. He brought his ideas to the institute’s director, Detlef Weigel. Weigel, who became his PhD advisor, called the project “much more ambitious than I could have imagined,” adding that Exposito-Alonso had “big ideas. [and] Big plans.”
This ambitious project led Expósito-Alonso to conduct a multi-site, years-long experiment, planting thousands of crops and using experimental evolution methods, to observe how plant genomes evolve when faced with rapid environmental changes such as climate change.
Expósito-Alonso first simulated drought conditions in a greenhouse. Arabidopsis thaliana Through plant genome-wide association studies, he found that drought-resistance genes came from two geographic locations: North Africa or near the Arctic. He extended the study to real-world conditions in the dry, hot climate of Spain and the more temperate climate of Germany. Weigel, who noticed that Expósito-Alonso easily convinced the entire lab to participate in the experiment, describes her as a “natural role model who leads by example.” The team soon planted 500 to 25,000 plants Oh. Thaliana Both genotypes spanned the locus and found that traits such as drought resistance came at the expense of other aspects of growth and fitness. The study also revealed that fitness of many genotypes decreased as temperature increased, suggesting that some Oh. Thaliana The population is in evolutionary danger.
However, Expósito-Alonso’s vision was bigger. “If we’re ever going to understand climate evolution more comprehensively, we need dozens of locations and we need to do it over many years,” he thought. “The difficulty was implementation,” he says. Toward the end of his PhD program, he teamed up with Niek Scheepens and François Vasseur, then at the University of Tübingen and the Max Planck Institute, respectively, to form the Genomics of Rapid Evolution in the Novel Environment Project (Green-net). They recruited scientists from universities in Europe, the Levant, and North America to examine genetic evolution in multiple climate zones. Each scientist began by planting a single set of over 200 seeds. Oh. Thaliana Strain Each year during the flowering season, the researchers harvested a flower from each plant and sent it back to the team for sequencing. The project lasted five years, allowing them to see which genetic variants enriched or lost over time at each location.
In the first three years of the project, some sites lost entire populations because the plants could not tolerate the conditions, and other sites saw population growth after an initial decline. This work highlights both the ability of species to adapt to future climate change and the risk of species extinction with population disruptions and loss of genetic diversity due to rapid environmental change.
To better understand how human activities are leading to a loss of genetic diversity, which may increase the risk of further extinction of species, Expósito-Alonso published the first global estimate of genetic diversity loss in 2022. It found that anthropogenic changes have already reduced global genetic diversity by 10%, with some species already losing 90% of genetic diversity. These findings suggest that the UN target of conserving 90 percent of global genetic diversity by 2030 may already be out of reach. This work on the loss of genetic diversity led Expósito-Alonso to serve as a delegate to the United Nations Convention on Biological Diversity in 2022.
Beyond research and global policy, Expósito-Alonso has built a reputation for leading a diverse, interdisciplinary team. Lauren Gillespie, a visiting assistant professor at the University of Michigan, was his first graduate student. He started in the lab at the beginning of the COVID-19 pandemic. “Moi did a great job of trying to build community despite the challenges of the pandemic,” she says, reflecting on the weekly happy hours, science talks, and a virtual Halloween event that Expósito-Alonso organized for the lab.
Expósito-Alonso is a pioneer at the intersection of computer science, evolutionary genetics, ecology, and plant biology and has built his lab by bringing together experts from multiple disciplines. For Gillespie, who comes from a computer science background, moving to the EcoEvo Lab was not an “easy transition” but she credits Expósito-Alonso’s guidance for accelerating her pace. “There were postdocs with computer science backgrounds, postdocs with plant microbiology backgrounds, and people from botany and bioinformatics,” she says. “It was really cool that he was able to play all these different backgrounds.” In addition to mentoring, Expósito-Alonso has led efforts to support minority students at the University of California and expanded experimental course work to learn about plant genetics in the wild.
“He’s a very authentic person,” Weigel says. “He is motivated by a desire to help a world that is changing rapidly.”
Please join us in congratulating Moisés Expósito-Alonso on receiving the 2026 GSA Early Career Medal for his contributions to modern genetics.
