JANUARY/FEBRUARY 2020. DISCOVER 19The discovery of the Tibetan mandible
solves that mystery, and also expands
the known Denisovan territory by more
than a thousand miles.
The Tibetan jawbone might answera few more questions, too. Scientists
have not been able to identify a number
of ancient human bones unearthed in
China; knowing what Denisovan jaws
look like may help them classify some of
the undescribed fossils.MORE THAN THIS
While Denisovan fossils have been few
and fragmentary, science has something
just as valuable: their DNA. The first
Denisovan genome was published in
2010, concurrently with news of their
discovery, and it’s allowed scientists to
probe their history from another angle
altogether. Multiple research teams
have recently compared the Denisovan
genome with those of modern humans,
turning up connections such as the
Tibetan EPAS1 gene. Other studies have
revealed that people in Southeast Asia
and Oceania have a small percentage of
different Denisovan genetic signatures.
In April in the journal Cell, research-
ers described a new wrinkle in theDenisovan story. By scanning the
genomes of 161 people living in
Indonesia and Papua New Guinea, the
scientists isolated surviving fragments
of Denisovan DNA in modern humans.
The team says it found strong indica-
tions that what we call the Denisovans
might actually have been three distinct
lineages of archaic human, spread
from Siberia to Southeast Asia. They
found the signatures of two separate
Denisovan populations in the DNA
from people in Indonesia and Papua
New Guinea — and both differed
from the Siberian Denisovans. One of
those groups looked as different from
Denisovans as from Neanderthals, which
suggests it may have been a separate
species.
“If we’re going to call Neanderthals
and Denisovans by a unique name,
which we do, then we should probably
call this other group by another name,”
says paper coauthor Murray Cox, of
New Zealand’s Massey University.Denisova Cave, Russia
(Fossils discovered 2008)
The Denisovan Range ExpandsFound in Baishiya Cave,
high on the Tibetan
Plateau (far left), a
partial jaw (above; digital
reconstruction, left)
is the first Denisovan
fossil found outside
Russia’s Denisova Cave.
Researchers continue
exploring Baishiya (right)
for additional evidence of
the mysterious lineage of
ancient humans.Baishiya Cave, China
(Fossil
confirmed 2019)Papua
New GuineaIndonesia(Multiple Denisovan lineages
confirmed 2019)