MEXICO CITY—In early June, evolutionary developmental biologist Elena Álvarez-Buylla received an out-of-the-blue phone call from the campaign of Andrés Manuel López Obrador, then the front-runner in Mexico’s presidential election, with a question. If López Obrador won, would she consider becoming the next director of the National Council of Science and Technology (Conacyt), the country’s science ministry and primary granting agency? “My first reaction was to say, ‘I can’t,’” recalls Álvarez-Buylla, a professor at the National Autonomous University of Mexico (UNAM) here. “I have a great passion for scientific research,” and she couldn’t imagine leaving the laboratory.

But after thinking it over for a few hours, her passion for public service took over. “I started to have a feeling that I couldn’t say no,” says Álvarez-Buylla, who founded and leads Mexico’s Union of Scientists Committed to Society (UCCS). “It doesn’t matter how big the personal sacrifice is. … This is a unique and historic moment” for Mexico.

López Obrador, a progressive populist, won the presidency in a landslide and will be sworn in on 1 December; Álvarez-Buylla is now preparing to leave the lab bench and assume her new role. She will be the president’s primary science adviser and determine priorities for Conacyt’s approximately $1.5 billion budget, which funds grants to scientists working in the public and private sectors and supports tens of thousands of Mexican students at home and abroad.

Many scientists are delighted that one of their own will lead Conacyt—most of Álvarez-Buylla’s predecessors were career administrators—and that she’ll be the first woman to do so. But critics worry about her opposition to genetically modified (GM) maize, which Álvarez-Buylla fears could spoil the country’s astonishing agricultural biodiversity. They also worry that in her commitment to socially relevant science, she may neglect basic research. A petition asking López Obrador to pick another director has gathered more than 1000 signatures.

“There’s not a clear boundary” between her research and her activism, says Rodrigo Álvarez Aguilera, a science teacher here and one of the petition’s organizers. Biochemist Luis Herrera Estrella, director of the National Laboratory of Genomics for Biodiversity in Irapuato, says Álvarez-Buylla is “a very good scientist” but calls her views on GM organisms “radical.”

Born into a family of scientists, Álvarez-Buylla studied plant biology at UNAM and received her doctorate from the University of California, Berkeley. She returned to UNAM in 1992, where she now runs several research groups. Colleagues praise her contributions to the understanding of plant root development and how plant genotypes influence their traits. “There’s no question that the research she does is fantastic,” says her former collaborator Chelsea Specht, a plant evolutionary biologist at Cornell University. “And her advocacy is based in very good research.”

That advocacy began after a 2001 Nature paper reported that genetic material from the cauliflower mosaic virus, a common addition to GM plants, had been found in native maize varieties sampled in Mexico’s southern state of Oaxaca—likely the result of cross-pollination from industrially grown crops whose origin remains unclear. The finding shocked many because of maize’s all-important role in Mexican history and culture. Maize domestication began here about 9000 years ago, and Mexico now boasts at least 59 native varieties, called landraces, each exquisitely adapted to regional environmental and climatic conditions. Some possess unusual characteristics; in August, for instance, researchers reported that a landrace from Oaxaca can fix nitrogen from the atmosphere with the help of microbes, a trait known from beans and other legumes but never before found in maize. The adaptation allows it to thrive in nitrogen-poor soils; breeding it into other maize varieties could be a boon for farmers and might help reduce fertilizer use. Other landraces may have useful adaptations as well.

Álvarez-Buylla led a team that confirmed the results of the 2001 study and has continued to hunt for transgenic DNA and any possible effects in Mexican landraces, work that helped her win Mexico’s National Science Prize in 2017. She says she has nothing against genetic engineering in itself; her team creates and studies GM plants in the lab, and such experiments should not be prohibited or restricted, she says. “I’m not a Luddite who is scared of technology.” But her own experiments have shown introduced genes can have unpredictable effects. “If a transgene is inserted in one part of [a plant’s] genome, it can be silenced and have no effect. If it’s inserted in another part, it can lead to a tremendous change,” she says. That unpredictability makes it too risky to allow GM maize anywhere near Mexico’s landraces, she argues. Planting GM maize in Mexico has been prohibited since 2013, pending the outcome of a lawsuit. Álvarez-Buylla has been an outspoken proponent of a permanent ban.

Herrera Estrella, who develops GM plants, disputes the risks. In the more than 50 years that landraces have cross-pollinated with commercial, industrially grown maize varieties, “it has had no negative effect. … It’s not contamination. It’s a completely natural biological process,” he says. If a foreign gene harms the growth or development of maize, farmers simply won’t use seeds from that individual plant the next year, and the damage won’t be passed on. “Conacyt needs a director with an expansive view of science and technology and the impact they could have on Mexico’s development. I think she has some very biased opinions,” he says.

Some scientists have also raised questions about Álvarez-Buylla’s plans to open dialogue between Mexico’s scientific community and Indigenous knowledge producers. “Mexico has the opportunity to contribute to the world something truly new that comes out of a deep hybridization” of those two forms of knowledge, Álvarez-Buylla says. Critics say that philosophy diminishes Western scientific values and achievements. They also worry basic research will suffer because of Álvarez-Buylla’s professed commitment to science that helps solve societal problems such as infant mortality and dwindling water supplies. “That’s a fallacy,” she says; Conacyt will remain supportive of basic research in all fields.

Álvarez-Buylla has little administrative experience, but she has proved herself capable at building and managing large research groups, says longtime colleague Daniel Piñro Dalmau, a plant population geneticist at UNAM. She has promised to improve Conacyt’s grant evaluation process, which many say is frustratingly quantitative and completely opaque. “Changing anything in Mexico is really hard,” Piñero Dalmau says. But Álvarez-Buylla “is deeply committed to this country.”

*Correction, 4 October, 3:10 p.m.: A previous version of the story misstated where Chelsea Specht works.