genetic ties to
Find suggests an additional,
recent New World migration
By Bruce Bower
A4,000-year-old Greenland man just entered the scien- tific debate over the origins of prehistoric populations in
A nearly complete sequence of nuclear
DNA extracted from strands of the long-dead man’s hair — the first such sequence
obtained from an ancient person — highlights a previously unknown and relatively recent migration of northeastern
Asians into the New World about 5,500
years ago, scientists say.
An analysis of differences, or mutations, at single base pairs in the ancient
Greenlander’s nuclear genome indicates
that his father’s ancestors came from
northeastern Siberia, report geneticist
Morten Rasmussen of the University of
Copenhagen and his colleagues in the
Feb. 11 Nature.
Three modern hunter-gatherer
groups in that region — the Nganasans,
Koryaks and Chukchis — display a closer
genetic link to the Greenland individual
than do Native American groups living
in cold northern areas of North America, Rasmussen says.
A largely complete mitochondrial
DNA sequence from the ancient man’s
hair, extracted by the same researchers
DNA from a 4,000-year-old man found near a Saqqaq site closely links him with the
Nganasans, Koryaks and Chukchis, suggesting a Siberia-to-Greenland migration.
in 2008, places his maternal ancestry in
northeastern Asia as well.
Danish-led excavations more than 20
years ago unearthed four fragmentary
bones and several hair tufts belonging
to this ancient man, dubbed Inuk. His
frozen remains were found at a site
from the Saqqaq culture, the earliest
known people to have inhabited Greenland. Saqqaq people lived in Greenland
from around 4,750 to 2,500 years ago.
One popular hypothesis traces Saqqaq
ancestry to Native American groups
that had settled Arctic parts of Alaska
and Canada by 11,000 years ago.
Inuk’s strong genetic ties to Siberian
populations suggest a different scenario.
“We’ve shown that this ancient individual was not related to Native Americans
but derived from an expansion of northeastern Asians into the New World and
across to Greenland,” says geneticist
and study coauthor Eske Willerslev of
the University of Copenhagen.
The team’s new comparative anal-
ysis of Inuk’s previously sequenced
mitochondrial DNA indicates that the
Saqqaqs diverged from their closest
present-day relatives, Siberian Chukchis,
an estimated 5,500 years ago. That cal-
culation implies that ancestral Saqqaqs
left their Asian relatives shortly before
departing for the New World and rap-
idly traversing that continent to reach
Greenland. No land bridge connected
Asia to North America at that time, so
migrants probably crossed the Bering
Strait from what’s now Russia to Alaska
by boat, Willerslev speculates.