Does Climbing Everest Alter Your Genetic Code?

Exposure to extreme environments can change our DNA. Everest climbers—and their twins—are the perfect study subjects.

Whether swabbing or stabbing, serving as lab rats on Everest was a new experience for Matt Moniz and Willie Benegas. (Damian Benegas)

At 21,000 feet on Mount Everest’s south side, inside a tent pitched beside a glacier at Camp II, Willie Benegas jabbed a needle into the arm of his climbing partner Matt Moniz. He was trying to get a blood sample, but Moniz’s veins had shriveled into threads because of the dehydrating effects of altitude. The freezing air temperature compounded the problem, causing Moniz’s body to shunt blood away from his extremities to warm his vital organs. Add in the fact that Benegas is a mountaineering guide, not a phlebotomist, and it’s not hard to imagine the whole episode as a macabre game of high-altitude darts, with Moniz’s arm as the target. “It was my payback for convincing Willie to do a science experiment while trying to summit Everest,” Moniz says.

Both Moniz and Benegas were collecting their blood—with the “vampire kit,” as they nicknamed it—as part of an ambitious new study that aims to understand the genetic changes that occur at extreme altitude. To differentiate between the changes caused by the climbers’ time on Everest last May and, say, the normal everyday changes of aging, scientists will compare the duo’s genetic code over time against the ultimate control subjects: the climbers’ twins. Moniz’s fraternal twin, Kaylee, and Benegas’ identical twin, Damian, provided blood samples from their homes at or near sea level.

(Damian Benegas)

“We know that time spent at high elevation will, for example, cause the body to produce more red blood cells to carry more oxygen,” says lead scientist Christopher E. Mason, PhD, a geneticist at Weill Cornell Medicine’s Department of Physiology and Biophysics. “What we don’t know is what’s happening at the detailed molecular level—which genes are creating that adaptation, which genes are responding to that stress, which genes are activated specifically when you climb the world’s tallest mountain?”

From Moniz’s and Benegas’ hard-earned blood samples, Mason will extract DNA, RNA, and plasma, the components needed to document each mountaineer’s genetic code, using sophisticated biomedical and computer technology. This genetic code determines how a person’s body makes cells and how those cells respond and adapt to the environment.

Mason took a similar approach when working on the 2017 NASA Twins Study. For that research, Mason compared the genetic code of astronaut Scott Kelly, after he spent one year living on the International Space Station, to the genetic code of Kelly’s identical twin brother, Mark, an astronaut who remained on Earth as a control subject. One of the early takeaways from that study is that Kelly’s “DNA repair genes” activated during his time in space, indicating that his body was experiencing ongoing damage, most likely from the heavy increase in radiation exposure. “We learned that there are indeed what you could call ‘space genes’ activated from the stressors of space travel,” Mason says.

Similarly, Mason suspects there are also “Everest genes.” That’s why foreign mountaineers cannot train themselves into the same level of fitness as a Sherpa. The advantage Sherpas have on Everest isn’t just sports physiology—it’s literally in their DNA. “Sherpas have an optimized genome that has evolved over thousands of years to create more red blood cells to be better at oxygen metabolism at extreme elevations,” Mason says. Being able to pinpoint the early adaptions happening in these two climbers’ genetic codes while on Everest puts us one step closer to the day when all climbers will be able to edit their genes to gain the same genetic advantage on Everest as Sherpas. The more immediate goal is better understanding of the genetic changes our bodies undergo in extreme circumstances, but Mason is optimistic about the long-term possibilities. “It’s still too early to say when,” he says. “It’s the early days for our understanding of such evolutionary selection and individual adaptations, but they light the way toward fundamental understanding of and protection for future climbers.”

For the Everest study, Mason is interested in the mountaineers’ microbiomes—the bacteria, fungi, viruses, and single-celled organisms that live in and around the human body, which scientists now know play nearly as important a role in how our genes are expressed as the genetic code itself. While on Everest, and before and after the climb, Benegas and Moniz swabbed the inside of their nostrils and the skin on their faces and collected fecal samples. Mason intends to use cells from the samples to chart the climbers’ microbiomes, creating a massive list of which species were found, how many, when, and where in the body. “It’s like taking a microbial census,” Mason says. It’s possible he’ll identify previously unknown microorganisms interacting with the human body on Everest.

(Damian Benegas)

While serving as lab rats on Everest was a new experience for Moniz and Benegas, they’re no strangers to extreme environments. Benegas, 50, is the co-founder of Benegas Brothers Expeditions, a renowned guiding company. He had a dozen Everest summits on his extensive climbing résumé before earning his 13th during the experiment. Moniz, 20, a student at Dartmouth College, began climbing at a remarkably young age. He summited Mount Elbrus and Mount Kilimanjaro by age ten and earned National Geographic Adventurer of the Year honors at age 12 for summiting the highest points in each of the 50 states. Moniz and Benegas first met on Mount Rainier in 2012 and have been climbing together ever since. Prior to the Everest experiment, they had climbed two other 8,000-meter Himalayan peaks together: Makalu and Cho Oyu.

The biggest challenge for Moniz and Benegas on Everest proved not to be drawing blood (which they did at Base Camp, Camp II, and back at Base Camp immediately after summiting). Instead, it was the logistics of getting their laboratory specimens off the mountain during the expedition. They had a 48-hour window from the time of collection for their biological samples to arrive in Kathmandu and be centrifuged and frozen at minus 80 degrees Celsius. “It was aggressive but possible, as long as everything went exactly as planned,” Moniz says.

To make the deadline, Moniz and Benegas made their collections in the early morning, well before the notorious afternoon weather rolls in, which typically grounds all helicopter flights to and from Everest. They placed the vials in a special collection box designed to keep them upright, and then sent the box with one of the helicopters on its way back to the village of Lukla after it delivered food and supplies to the mountain. A colleague picked up the sample box from the airstrip in Lukla and transferred it to a fixed-wing plane for departure to Kathmandu, where another colleague picked it up and drove it to the lab for processing.

“It wouldn’t have been possible without years of experience on Everest, without the network of friends who were really excited about what we were doing and willing to help us any way they could,” Benegas says.

Mason is currently waiting for the shipment of specimens from Kathmandu, where they’ve been held up for several weeks in the freezer as the required paperwork goes through—proper protocol when conducting scientific research on live humans. As for the participants, Benegas says the Everest twins study marks his official retirement from the world’s tallest peak. Moniz, meanwhile, is just getting started and hopes to continue mixing science and high-altitude mountaineering—although he’d prefer not to have to deal with the vampire kit again.

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