January/February 2019^ DISCOVER^55
FROM TOP: IVAR BRYNJOLFSSON/THE NATIONAL MUSEUM OF ICELAND; ARTOKOLORO QUINT LOX LIMITED/ALAMY STOCK PHOTO; IAN R.CARTWRIGHT/INSTITUTE OF ARCHAEOLOGY OXFORD UNIVERSITY
Iceland’s Past and Present
Iceland was settled roughly 1,000 years ago
by Vikings and their slaves. As might be expected,
the genomes of 27 of these early inhabitants showed
mixed Gaelic and Norse ancestry, according to a
June Science paper. Modern Icelanders are largely
genetically distinct from their distant Viking ancestors,
however. The new study suggests the DNA disparity,
not uncommon in small island populations, is a clear
case of genetic drift: Chance determined which genes
got passed to subsequent generations. Social factors,
such as selective mating based on status, also may
have played a role.
The Steppe HighwayThe Eurasian steppes — thousands of miles of
grassland between Hungary and China — have been the
scene of human migrations for millennia. The genomes of
211 individuals who lived there between 500 and 11,000 years
ago were published by geneticists in Nature in May and in
Science in June. Some of the discoveries: Hunter-gatherers
with no genetic ties to nearby farmers likely domesticated
horses 5,000 years ago in Kazakhstan;
Scythian nomads who ruled
the steppe during the first
millennium B.C. had genetically
diverse ancestries; and
an 1,800-year-old
Hun from
Kyrgyzstan
harbored flea-borne
bubonic plague,
suggesting the pathogen
spread to Europe along
the Silk Road, a vast
network of trade routes
across Europe and Asia.Africa’s New Frontier
Researchers have sequenced the oldest
human aDNA so far recovered in Africa. Excavated
at a burial site in Morocco, seven 15,000-year-old
skeletons showed genetic ties to ancient Near
Easterners and modern sub-Saharan Africans,
proving there was interaction across the desert
among human groups, researchers reported in
Science in May.
Technological advances and the knowledge that
a skull’s petrous bone sometimes preserves aDNA
even in arid climates has researchers scrambling
to Africa. One of the largest projects has sampled
skeletal remains from collections in Tanzania,
Zambia and Kenya. The material currently is being
sequenced at Harvard Medical School.4
2
3
4
2
3
Louise Humphrey, left, of the Natural History Museum in London, was part of the
international team that excavated seven ancient skeletons in Morocco. At right
is a skull fragment from one of the individuals.At more than 1,000 years old, remains of the first Icelanders, such as this
skeleton, are genetically distinct from the island nation’s modern population.A bronze statuette
of a mounted
archer, about
2,500 years old, is
an artifact of the
genetically diverse
Scythian culture.Eurasian^ steppes2 cm