could refine human microbiome therapies and add
a needed dose of science to probiotics.
There might not be much time left for this quest.
Over the past 50 years, hundreds of thousands of
Mongolian herders have abandoned the steppes,
their herds, and their traditional lifestyle, flocking
to Ulaanbaatar. Around 50 percent of the country’s
population, an estimated 1.5 million people, now
crowds into the capital.
In summer 2020, Warinner’s team will return to
Khatgal and other rural regions to collect mouth
swabs and fecal specimens from herders, the last
phase in cataloging the traditional Mongolian
micro biome. She recently decided she’ll sample
residents of Ulaanbaatar too, to see how urban
dwelling is altering their bacterial balances as they
adopt new foods, new ways of life, and, in all like-
lihood, newly simplified communities of microbes.
Something important, if invisible, is being lost,
Warinner believes. On a recent fall morning, she
was sitting in her sunlit office in the Peabody
Museum of Archaeology and Ethnography on Har-
vard’s campus. Mostly unpacked from her latest
trans-Atlantic move, she was contemplating a
creeping, yurt-by-yurt extinction event.
It’s a conundrum vastly different in size, but not in
scale, from those facing wildlife conservationists the
world over. “How do you restore an entire ecology?”
she wondered. “I’m not sure you can. We’re doing
our best to record, catalog, and document as much
as we can, and try to figure it out at the same time.”
Preserving Mongolia’s microbes, in other words,
won’t be enough. We also need the traditional
knowledge and everyday practices that have sus-
tained them for centuries. Downstairs, display
cases hold the artifacts of other peoples— from
the Massachusett tribe that once lived on the land
where Harvard now stands to the Aztec and Inca
civilizations that used to rule vast stretches of
Central and South America—whose traditions are
gone forever, along with the microbial networks
they nurtured. “Dairy systems are alive,” Warinner
says. “They’ve been alive, and continuously cul-
tivated, for 5,000 years. You have to grow them
every single day. How much change can the system
tolerate before it begins to break?”of bacteria that make up our microbiomes
aren’t passive passengers. They play an
active—if little understood—role in our
health, helping regulate our immune
systems and digest our food.
Over the past two centuries, industrial-
ization, sterilization, and antibiotics have
dramatically changed these invisible eco-
systems. Underneath a superficial diversity
of flavors— mall staples like sushi, pad thai,
and pizza— food is becoming more and more
the same. Large-scale dairies even fer-
ment items like yogurt and cheese using
lab-grown starter cultures, a $1.2 billion in-
dustry dominated by a handful of industrial
producers. People eating commoditized cui-
sine lack an estimated 30 percent of the gut
microbe species that are found in remote
groups still eating “traditional” diets. In
2015, Warinner was part of a team that found
bacteria in the digestive tracts of hunter-
gatherers living in the Amazon jungle that
have all but vanished in people consuming a
selection of typical Western fare.
“People have the feeling that they eat a
much more diverse and global diet than
their parents, and that might be true,” Rest
says, “but when you look at these foods on a
microbial level, they’re increasingly empty.”
A review paper in Science in October 2019
gathered data from labs around the world
beginning to probe if this dwindling variety
might be making us sick. Dementia, diabetes,
heart disease, stroke, and certain cancers are
sometimes termed diseases of civilization.
They’re all associated with the spread of
urban lifestyles and diets, processed meals,
and an tibiotics. Meanwhile, food intolerances
and intestinal illnesses like Crohn’s disease
and irritable bowel disease are on the rise.
Comparing the microbiome of Mongolian
herders to samples from people consuming
a more industrialized diet elsewhere in
the world could translate into valuable
insights into what we’ve lost—and how to
get it back. Identifying the missing species
SPRING
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