Monkeys that survived a devastating hurricane in Puerto Rico were prematurely aged by the experience, a study has found.
Scientists say the findings suggest that an increase in extreme weather around the world may have negative biological consequences for the humans and animals affected.
The scientists said the rhesus macaques that lived through Hurricane Maria in 2017 appeared to have aged by about two years more than expected, equivalent to seven or eight years of human life.
“Studying the impact of exposure to adversity is depressing stuff. You’re showing … these have negative impacts at multiple levels, and here at the molecular level … that’s long term,” said Noah Snyder-Mackler, a professor at the Center for Evolution and Medicine of Arizona State University, and one of the authors of the paper, published in the journal PNAS.
Snyder-Mackler and colleagues had been collecting blood samples from the free-ranging rhesus macaques in the conservation centre at Cayo Santiago island, near Puerto Rico, since 2014. Rhesus macaques are the most studied monkey in science because they are biologically quite similar to humans. After Hurricane Maria hit, the blood samples collected as much as a year later showed significant changes to the monkeys’ immune systems.
By using genomic sequencing technology, the researchers found that up to 4% of the monkeys’ genes were showing changes. There was a decrease in the genes associated with properly folding proteins so they can carry out their functions seamlessly, something seen naturally as monkeys and humans age. There was also an increase in the genes associated with inflammatory responses. This is also commonly seen as primates age, with chronic inflammation sometimes leading to cardiovascular disease and some cancers.
“I think that it resonates when we say, oh, something molecular is actually changing in our cells,” said Marina Watowich, a graduate student in the SMack Lab at the University of Washington, and the lead author of the paper. “And that’s going to have long-term effects.”
Watowich said it was important to note that the study looked at the average changes in the macaque population, meaning not all the monkeys were sampled every year, and some fared much better than others.
“This is not like an all or nothing, like every single animal was negatively impacted after the storm,” Watowich said. “There was actually quite a lot of variation. And so that’s what we’re getting into next is who’s doing well after these events and who’s not doing well, and how can we make everyone like those ones who weren’t really affected?”