Topic ID #31163 - posted 2/12/2014 2:28 PM

Oldest Burial Yields DNA Evidence of First Americans



Jennifer Palmer

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Oldest Burial Yields DNA Evidence of First Americans
Ancient genome confirms link between Asians and Native Americans.

Ker Than for National Geographic Published February 12, 2014

DNA harvested from the remains of an infant buried 13,000 years ago confirms that the earliest widespread culture in North America was descended from humans who crossed over to the New World from Asia, scientists say.

The research, detailed in this week's issue of the journal Nature, also suggests that many contemporary Native Americans are direct descendants of the so-called Clovis people, whose distinctive stone tools have been found scattered across North America and Mexico.


Read the full article here.




Post ID#20434 - replied 2/14/2014 12:28 AM



Charlie Hatchett

M. Rasmussen et al. “The genome of a Late Pleistocene human from a Clovis burial site in western Montana,” Nature, doi:10.1038/nature13025, 2014.

Clovis, with its distinctive biface, blade and osseous technologies, is the oldest widespread archaeological complex defined in North America, dating from 11,100 to 10,700 14C years before present (BP) (13,000 to 12,600 calendar years BP)1, 2. Nearly 50 years of archaeological research point to the Clovis complex as having developed south of the North American ice sheets from an ancestral technology. However, both the origins and the genetic legacy of the people who manufactured Clovis tools remain under debate. It is generally believed that these people ultimately derived from Asia and were directly related to contemporary Native Americans2. An alternative, Solutrean, hypothesis posits that the Clovis predecessors emigrated from southwestern Europe during the Last Glacial Maximum4. Here we report the genome sequence of a male infant (Anzick-1) recovered from the Anzick burial site in western Montana. The human bones date to 10,705 ±35 14C years BP (approximately 12,707–12,556 calendar years BP) and were directly associated with Clovis tools* We sequenced the genome to an average depth of 14.4× and show that the gene flow from the Siberian Upper Palaeolithic Mal’ta population**5 into Native American ancestors is also shared by the Anzick-1 individual and thus happened before 12,600 years BP. We also show that the Anzick-1 individual is more closely related to all indigenous American populations than to any other group. Our data are compatible with the hypothesis that Anzick-1 belonged to a population directly ancestral to many contemporary Native Americans. Finally, we find evidence of a deep divergence in Native American populations that predates the Anzick-1 individual.

[www.nature.com]

* See following article
** See last article





Waters, M. and Stafford, T. 2007 Redefining the age of Clovis: implications for the peopling of the Americas. Science 315:1122–6

"... Anzick, Montana: The Anzick site in Montana is reported to be a Clovis burial and cache. At Anzick, 12 radiocarbon dates were obtained from the cranial elements of a purported Clovis infant skeleton and 2 dates on associated bone foreshafts. Collagen extracted from the foreshafts yielded an average age of 11,040 + 35 14C yr B.P. (S7). The human skeletal remains were dated during three separate research programs. The first batch of seven dates on bone comprise five chemical fractions that were considered reliable and averaged to 10,680 + 50 14C yr B.P. (S2). Later, a single purified collagen sample yielded a date of 11,550 + 60 14C yr B.P. (CAMS-35912). This measurement is rejected because subsequent dating of the same XAD fraction and preceding fractions from newly sampled bone did not replicate the 11,550 14C yr B.P. result. The source of the contaminating 14C-depleted carbon is unknown. A more recent series of dates from a single cranial fragment provided four new radiocarbon ages. These fractions confirm previous date estimates for the skeleton of 10,705 + 35 14C yr B.P. The 14C dates on the skeleton versus the dates on the bone foreshafts suggest that the skeletal remains and Clovis artifacts may not be related and that the foreshaft ages more accurately date the site. The 10,700 year old human remains could post-date the Clovis cache, but additional research is needed to resolve this issue. A more recent, late Paleoindian or early Archaic human skeleton was also found at the site (S7). The association of any of the human remains with the Clovis cache is problematic because the site had been excavated accidentally with heavy machinery before the human bones and artifacts were recognized and later recovered at some distance from the actual site. Thus, the directly dated Clovis artifacts—the foreshafts—appear to accurately date the site..."

[www.sciencemag.org]





Raghavan M. et al. Upper Palaeolithic Siberian genome reveals dual ancestry of Native Americans. Nature (2013)

The origins of the First Americans remain contentious. Although Native Americans seem to be genetically most closely related to east Asians1, 2, 3, there is no consensus with regard to which specific Old World populations they are closest to4, 5, 6, 7, 8. Here we sequence the draft genome of an approximately 24,000-year-old individual (MA-1), from Mal’ta in south-central Siberia9, to an average depth of 1×. To our knowledge this is the oldest anatomically modern human genome reported to date. The MA-1 mitochondrial genome belongs to haplogroup U, which has also been found at high frequency among Upper Palaeolithic and Mesolithic European hunter-gatherers10, 11, 12, and the Y chromosome of MA-1 is basal to modern-day western Eurasians and near the root of most Native American lineages5. Similarly, we find autosomal evidence that MA-1 is basal to modern-day western Eurasians and genetically closely related to modern-day Native Americans, with no close affinity to east Asians. This suggests that populations related to contemporary western Eurasians had a more north-easterly distribution 24,000 years ago than commonly thought. Furthermore, we estimate that 14 to 38% of Native American ancestry may originate through gene flow from this ancient population. This is likely to have occurred after the divergence of Native American ancestors from east Asian ancestors, but before the diversification of Native American populations in the New World. Gene flow from the MA-1 lineage into Native American ancestors could explain why several crania from the First Americans have been reported as bearing morphological characteristics that do not resemble those of east Asians2, 13. Sequencing of another south-central Siberian, Afontova Gora-2 dating to approximately 17,000 years ago14, revealed similar autosomal genetic signatures as MA-1, suggesting that the region was continuously occupied by humans throughout the Last Glacial Maximum. Our findings reveal that western Eurasian genetic signatures in modern-day Native Americans derive not only from post-Columbian admixture, as commonly thought, but also from a mixed ancestry of the First Americans.

Raghavan M. et al. Upper Palaeolithic Siberian genome reveals dual ancestry of Native Americans. Nature (2013)

[www.nature.com]



Charlie Hatchett

PreClovis Artifacts from Central Texas

http://www.pre-clovis.com
http://www.forum.pre-clovis.com
http://www.blog.pre-clovis.com

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