Evidence of Ice Age human migrations from China to the Americas and
Japan

Date:
May 9, 2023
Source:
Cell Press
Summary:
Scientists have used mitochondrial DNA to trace a female lineage
from northern coastal China to the Americas. By integrating
contemporary and ancient mitochondrial DNA, the team found evidence
of at least two migrations: one during the last ice age, and one
during the subsequent melting period. Around the same time as the
second migration, another branch of the same lineage migrated to
Japan, which could explain Paleolithic archeological similarities
between the Americas, China, and Japan.


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FULL STORY ========================================================================== Scientists have used mitochondrial DNA to trace a female lineage from
northern coastal China to the Americas. By integrating contemporary
and ancient mitochondrial DNA, the team found evidence of at least two migrations: one during the last ice age, and one during the subsequent
melting period. Around the same time as the second migration, another
branch of the same lineage migrated to Japan, which could explain
Paleolithic archeological similarities between the Americas, China,
and Japan. The study appears May 9 in the journal Cell Reports.

"The Asian ancestry of Native Americans is more complicated than
previously indicated," says first author Yu-Chun Li, a molecular
anthropologist at the Chinese Academy of Sciences. "In addition to
previously described ancestral sources in Siberia, Australo-Melanesia,
and Southeast Asia, we show that northern coastal China also contributed
to the gene pool of Native Americans." Though it was long assumed that
Native Americans descended from Siberians who crossed over the Bering
Strait's ephemeral land bridge, more recent genetic, geological, and archeological evidence suggests that multiple waves of humans journeyed
to the Americas from various parts of Eurasia.

To shed light on the history of Native Americans in Asia, a team of
researchers from the Chinese Academy of Sciences followed the trail of an ancestral lineage that might link East Asian Paleolithic-age populations
to founding populations in Chile, Peru, Bolivia, Brazil, Ecuador, Mexico,
and California. The lineage in question is present in mitochondrial DNA,
which can be used to trace kinship through the female line.

The researchers scoured over 100,000 contemporary and 15,000 ancient
DNA samples from across Eurasia to eventually identify 216 contemporary
and 39 ancient individuals belonging to the rare lineage. By comparing
the accumulated mutations, geographic locations, and carbon-dated age
of each of these individuals, the researchers were able to trace the
lineage's branching path.

They identified two migration events from northern coastal China to the Americas, and in both cases, they think that the travelers probably set
dock in America via the Pacific coast rather than by crossing the inland ice-free corridor (which would not have opened at the time).

The first radiation event occurred between 19,500 and 26,000 years ago
during the Last Glacial Maximum, when ice sheet coverage was at its
greatest and conditions in northern China were likely inhospitable for
humans. The second radiation occurred during the subsequent deglaciation
or melting period, between 19,000 and 11,500 years ago. There was a rapid increase in human populations at this time, probably due to the improved climate, which may have fueled expansion into other geographical regions.

The researchers also uncovered an unexpected genetic link between Native Americans and Japanese people. During the deglaciation period, another
group branched out from northern coastal China and traveled to Japan. "We
were surprised to find that this ancestral source also contributed to
the Japanese gene pool, especially the indigenous Ainus," says Li.

This discovery helps to explain archeological similarities between the Paleolithic peoples of China, Japan, and the Americas. Specifically, the
three regions share similarities in how they crafted stemmed projectile
points for arrowheads and spears. "This suggests that the Pleistocene connection among the Americas, China, and Japan was not confined to
culture but also to genetics," says senior author Qing-Peng Kong, an evolutionary geneticist at the Chinese Academy of Sciences.

Though the study focused on mitochondrial DNA, complementary evidence from
Y chromosomal DNA suggests that male ancestors of Native Americans also
lived in northern China at around the same time as these female ancestors.

This study adds another piece to the puzzle that is Native American
ancestry, but many other elements remain unclear. "The origins of several founder groups are still elusive or controversial," says Kong. "Next,
we plan to collect and investigate more Eurasian lineages to obtain a
more complete picture on the origin of Native Americans."
* RELATED_TOPICS
o Fossils_&_Ruins
# Archaeology # Ancient_Civilizations # Ancient_DNA
# Human_Evolution # Early_Humans # Origin_of_Life #
Cultures # Evolution
* RELATED_TERMS
o Human_migration o Indigenous_peoples_of_the_Americas o
Chichen_Itza o RNA o Maya_civilization o Little_Ice_Age o
Geologic_temperature_record o The_Genographic_Project

========================================================================== Story Source: Materials provided by Cell_Press. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Li and Gao et al. Mitogenome evidence shows two radiation events and
dispersals of matrilineal ancestry from northern coastal
China to the Americas and Japan. Cell Reports, 2023 DOI:
10.1016/j.celrep.2023.112413 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/05/230509122008.htm

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