Discover - USA (2020-01 & 2020-02)

18 DISCOVERMAGAZINE.COM

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Since 2008, when their fragmentary

fossils first turned up in a Siberian

cave, the Denisovans have been the

most mysterious branch of the human

family tree. The archaic humans, like

Neanderthals, lived at the same time as

early Homo sapiens but have been extinct

for tens of thousands of years.

For nearly a decade, we’ve known

Denisovans from only one site, which

yielded just a shard of finger bone and a

few teeth from four individuals — and

ancient DNA extracted from the scant

remains.

In 2019, however, a series of discov-

eries revealed our evolutionary kin

in greater detail than ever, answering

some questions but also presenting

new mysteries. One thing is clear: The

Denisovans were much more complex

than we thought, occupying diverse

and sometimes extreme environments

spread over much of Asia.

In March, researchers announced

that they had found two small skull

fragments — the first known pieces of

a Denisovan braincase — belonging to

a fifth individual in Denisova Cave, in

the Altai Mountains of southern Siberia.

However, the biggest news about our

mysterious extinct cousins came from

outside their namesake cave.

THE HIGH LIFE

Writing in Nature in May, a separate team

announced that a partial mandible, or

jawbone, found in a cave on the Tibetan

Plateau, came from a Denisovan. It was

the first time a Denisovan had been found

outside Denisova Cave. And, at around

160,000 years old and about 2 miles above

sea level, it revealed that archaic humans

lived at extreme altitudes long before our

own species did.

The discovery also cleared up a mod-

ern mystery. Scientists have known that

modern-day Tibetans possess a gene

inherited from Denisovans thousands

of years ago, when our species inter-

bred. The gene, known as EPAS1, alters

the body’s production of hemoglobin,

a protein in red blood cells that car-

ries oxygen, and helps them survive

high-altitude environments. However,

because Denisova Cave is not at high

altitude, researchers had puzzled over

why individuals living there would be

adapted for the high life.

Decoding the

Denisovans

BY NATHANIEL SCHARPING