54 DISCOVERMAGAZINE.COM
MAP: ALISON MACKEY/DISCOVER. BOTTOM: ERIC S. CARLSON IN COLLABORATION WITH BEN POTTERIt’s been a blockbuster year for genomes in archaeology.
Researchers reported ancient DNA (aDNA) from over
1,400 human remains, more than doubling the number
of individuals who have yielded ancient genomic data.
Many of the sequences have come from Europe and
other regions with temperate climates, but researchers
also recovered samples from environments long
considered too hot and humid for aDNA preservation.
The surge in aDNA data is due to cheaper, faster
methods for reading genetic code, as well as the
discovery three years ago that the dense petrous bone of
the inner ear can preserve up to 100 times more aDNAthan other skeletal parts. It’s a “big game changer...
this little vault of aDNA,” says Elizabeth Sawchuk,
a postdoctoral archaeologist at Stony Brook University.
The volume of genomic data analyzed enabled
researchers to test some big hypotheses, including
scenarios for the irst migrations of people to the
Americas and the spread of Indo-European
language speakers. Along the way,
intimate aspects of our ancestors have
been revealed, such as skin
color and the diseases they
sometimes had to endure.Early Americans
Around 11,500 years ago in the Tanana River Basin in central Alaska, bodies of
two infants were covered in red pigment and buried in a grave. The babies belonged to a previously
unknown, genetically distinct group of Native Americans, according to an analysis in Nature in January.
About 20,000 years ago, as people were migrating across the land bridge between Siberia and Alaska, this
population branched off from the others and eventually moved into the northern part of North America.
Other people who crossed the bridge at this time continued south, deep into the Americas. This migrating group
split into two distinct populations between 14,600 and 17,500 years ago, and later reunited en route to South
America, according to a separate study published in Science in June. The researchers analyzed 91 genomes, mainly
from California’s Channel Islands and Ontario, Canada, making it the largest aDNA study so far in the Americas.ARCHAEOLOGY
Ancient DNA analysis unlocks the complexity of human migrations,
and drones and lasers reveal hidden structures. BY BRIDGET ALEX
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Genetic material collected from human remains in Alaska, dated to about 11,500 years ago, has provided researchers with new
information about the movement of people into the Americas from Siberia around 20,000 years ago.