MEXICO CITY—For Andrés Moreno-Estrada, the news was welcome but the timing, terrible. Moreno-Estrada, who hunts for genetic variations linked to disease, recently learned that he had won a 13-million-peso grant from Mexico and the United Kingdom to sequence DNA from blood samples in a public health biobank. But 13 million pesos isn’t what it was before Donald Trump assumed the U.S. presidency. When the population geneticist at the National Laboratory of Genomics for Biodiversity (LANGEBIO) in Irapuato, Mexico, submitted his proposal in November 2015, the exchange rate was 16 pesos to the dollar, and his grant would have been worth $812,500. Now, the rate is 21 pesos to the dollar. “There’s no way I can do what I committed to,” he says, unless he raises more money.

The fall of the peso, provoked in part by Trump’s insistence on building a border wall and making Mexico pay for it, is one contributor to the waves of angst sweeping through the Mexican science community. “Every time Trump tweets something about Mexico, the peso takes a hit,” says Daniela Robles-Espinoza, a cancer geneticist who is outfitting a new lab at the International Laboratory for Human Genome Research in Juriquilla, Mexico. As the dollar value of grants shrinks, so does buying power: Mexican scientists purchase most of the research materials and equipment they use from the United States. The peso depreciation also strains Mexican scientists hoping to travel to international conferences or publish in journals that require publication fees.

Trump’s harsh stance toward Mexico has made scientists here nervous about the fate of U.S. funding for cross-border collaborations. “The worry is that [Trump] will limit, or perhaps end, some of the academic exchange we have,” either through new regulations or by cutting off money for collaborations, says Jaime Urrutia-Fucugauchi, a geophysicist at the National Autonomous University of Mexico (UNAM) here and president of the Mexican Academy of Sciences. The U.S. National Science Foundation currently supports about 200 projects with Mexican collaborators. Mexico’s National Council for Science Technology (Conacyt) said in a statement that “it is an opportune moment” to expand collaborations with other countries including the European Union and China.

Economic turmoil could also harm industries that support innovation in Mexico. Many Mexican scientists and engineers work in auto manufacturing, aerospace, and pharmaceuticals. Trump has threatened to impose tariffs on cars assembled in Mexico, which has already prompted Ford to abandon plans for a new factory in San Luis Potosí. If foreign companies that have been hiring Mexicans with advanced degrees stop doing business in the country, “that would be a true disaster,” says Luis Herrera-Estrella, director of LANGEBIO. “It would cause terrible unemployment in Mexico.”

Geography made us cousins. This is like breaking up a family. Carlos Gay, National Autonomous University

Amid nationwide calls to support Mexican businesses and boycott U.S. firms, Lorenza Haddad sees a glimmer of hope. A Mexican geneticist who studied in the United States, she’s the CEO of Código 46, a new company in Cuernavaca that plans to offer genotyping services for personalized medicine to Mexican clients starting next month. “The way Mexico has been talked about lately, it puts us on the map a lot more than before,” she says.

Chilly relations may also change the calculus for promising young Mexican scientists planning to go abroad. Like scientists from countries targeted by Trump’s immigration order, Mexican researchers who normally would come to the United States for graduate training or postdocs say they may find a warmer welcome elsewhere. In 2016 Conacyt awarded 1550 grants to graduate students and researchers studying in the United States, making it the No. 1 destination for Mexican scientists abroad. Santiago Rábade, who is working toward his master’s degree in earth sciences at UNAM, says that many peers are now considering pursuing degrees in the European Union or Japan—“where there is less anti-Mexican sentiment.” Rábade says he still plans to apply to doctoral programs at U.S. universities, but he is uneasy. “I’m making a major life decision. Is the United States really a good place to be for 5 years?” he asks. “It no longer seems like a friendly place.”

“Geography made us cousins,” says UNAM climate scientist Carlos Gay. “This is like breaking up a family.”

Additional reporting by Jeffrey Mervis.