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Population Y, the real First Americans?
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[QUOTE]Originally posted by the lioness,: [QB] [QUOTE]Originally posted by BrandonP: [QUOTE] Jonnes Genealogy The Mystery of Population Y Disappointingly, none of the 49 ancient samples in the Cell study revealed an Australasian genetic signature. One sample from the [b]Science study, however did: the 10,400-year-old [b]Lagoa Santa remains in Brazil.[/b] That would appear to be evidence that descendants of the “ghost” population known as Population Y were in South America at least 10,000 ya.[/b] [/QUOTE][/QUOTE] https://www.science.org/lookup/doi/10.1126/science.aab3884 SCIENCE 2015 [b]Genomic evidence for the Pleistocene and recent population history of Native Americans[/b] MAANASA RAGHAVAN CONCLUSION Our results provide an upper bound of ~23 ka on the initial divergence of ancestral Native Americans from their East Asian ancestors, followed by a short isolation period of no more than ~8000 years, and subsequent entrance and spread across the Americas. The data presented are consistent with a single-migration model for all Native Americans, with later gene flow from sources related to East Asians and, indirectly, Australo-Melanesians. The single wave diversified ~13 ka, likely within the Americas, giving rise to the northern and southern branches of present-day Native Americans. Fig. 1 Origins and population history of Native Americans. Additionally, we see a weak signal related to Australo-Melanesians in some Native Americans, which may have been mediated through East Asians and Aleutian Islanders We found that some American populations—including the Aleutian Islanders, Surui, and Athabascans—are closer to Australo-Melanesians as compared with other Native Americans, such as North American Ojibwa, Cree, and Algonquin and the South American Purepecha, Arhuaco, and Wayuu (fig. S10). The Surui are, in fact, one of closest Native American populations to East Asians and Australo-Melanesians, the latter including Papuans, non-Papuan Melanesians, Solomon Islanders, and South East Asian hunter-gatherers such as Aeta (fig. S10). We acknowledge that this observation is based on the analysis of a small fraction of the whole-genome and SNP chip genotype data sets—especially for the Aleutian Islander data, which is heavily masked owing to recent admixture with Europeans (28)—and that the trends in the data are weak. Nonetheless, if it proves correct, these results suggest that there may be a distant Old World signal related to Australo-Melanesians and East Asians in some Native Americans.[b] The widely scattered and differential affinity of Native Americans to the Australo-Melanesians, ranging from a strong signal in the Surui to a much weaker signal in northern Amerindians such as Ojibwa, points to this gene flow occurring after the initial peopling by Native American ancestors.[/b] However, how this signal may have ultimately reached South America remains unclear. One possible means is along a northern route via the Aleutian Islanders, previously found to be closely related to the Inuit (39), who have a relatively greater affinity to East Asians, Oceanians, and Denisovan than Native Americans in both whole-genome and SNP chip genotype data–based D tests (table S10 and figs. S10 and S11). On the basis of archaeological evidence and mtDNA data from ancient and modern samples, the Aleutian Islands are hypothesized to have been peopled as early as ~9 ka by “Paleo-Aleuts” who were succeeded by the “Neo-Aleuts,” with present-day Aleutian Islanders potentially resulting from admixture between these two populations (52, 53). Perhaps their complex genetic history included input from a population related to Australo-Melanesians through an East Asian continental route, and this genomic signal might have been subsequently transferred to parts of the Americas, including South America, through past gene flow events (Fig. 1). Evidence for this gene flow is supported with diCal2.0 and MSMC analyses showing a weak but recent gene flow into South Americans from populations related to present-day Northeast Asians (Koryak) (Fig. 2C and table S11C), who might be considered a proxy for the related Aleutian Islanders. [b]The results of analyses based on craniometric data thus are highly sensitive to sample structure and the statistical approach and data filtering used (51). Our morphometric analyses suggest that these ancient samples are not true relicts of a distinct migration as claimed and hence do not support the Paleoamerican model. Similarly, our genomic data also provide no support for an early migration of populations directly related to Australo-Melanesians into the Americas.[/b] [/QB][/QUOTE]
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