Genetics: Australasian-related ancestry in
some Amazonian populations
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Nature
Embargo
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London: Tuesday 21 July 2015 18:00 (BST)
New York: Tuesday 21 July 2015 13:00 (EDT)
Tokyo: Wednesday 22 July 2015 02:00 (JST)
Sydney: Wednesday 22 July 2015 03:00 (AEST)
Some Amazonian Native Americans descend partly from a founding population related to
indigenous Australasians, shows an analysis of genome-wide data published
in Nature this week. The study hints that the Americas may have been founded by a more
diverse set of populations than previously accepted.
Most genetic studies have suggested that the Americas were peopled by a single founding
population of Eurasian origin, which probably migrated across the Bering land bridge from
Asia more than 15,000 years ago. However, some morphological studies offer a more
complex picture, as the northeast Asian affinities of present-day Native Americans contrast
with some early American skeletons that share traits with present-day Australasians.
David Reich and colleagues analysed genome-wide data from 30 Native American
populations of Central and South America, and from 197 non-American populations
sampled worldwide. They find that some Native American populations from Amazonia
derive a small proportion of their ancestry from a population that is more closely related to
indigenous Australians, New Guineans and Andaman Islanders than to present-day Eurasians
or Native Americans. Present-day Native American populations from North and Central
America seem to lack this genetic signature.
The authors propose that the ‘Population Y’ (named for Ypykuéra, which means ‘ancestor’ in
the Tupi language family) that contributed Australasian-related ancestry to Amazonians was
already mixed with a lineage related to Native Americans at the time it reached Amazonia.
How and when Population Y ancestry reached South America remains uncertain; genomewide analysis of ancient remains from across the Americas may provide further insights.
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Article and author details
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Genetic evidence for two founding populations of the Americas
Corresponding Author
David Reich
Harvard Medical School, Boston, Massachusetts, United States
Email: reich@genetics.med.harvard.edu, Tel: +1 617 432 6548
DOI
10.1038/nature14895
Online paper*
http://nature.com/articles/doi:10.1038/nature14895
* Please link to the article in online versions of your report (the URL will go live after the embargo
ends).
IMAGES
Image 1:
Caption: Deep genetic affinities between Amazonian populations in South America, and Australasians
(indigenous New Guineans, Australians, and Onge from the Andaman Islands); warmer colors
indicate the strongest affinities. These patterns reflect the finding that Amazonian populations derive
some of their ancestry from an ancient ‘Population Y’ (for Ypykuéra, which means ‘ancestor’ in the
Tupi language family) that did not contribute much or at all to other Native Americans.
Credit: Pontus Skoglund, Harvard Medical School
Image 2:
Caption: Deep genetic affinities between Amazonian populations in South America, and Australasians
(indigenous New Guineans, Australians, and Onge from the Andaman Islands); warmer colors
indicate the strongest affinities. These patterns reflect the finding that Amazonian populations derive
some of their ancestry from an ancient ‘Population Y’ (for Ypykuéra, which means ‘ancestor’ in the
Tupi language family) that did not contribute much or at all to other Native Americans.
Credit: Pontus Skoglund, Harvard Medical School