SummaryWe report genome-wide ancient DNA from 49 individuals forming four parallel time transects in Belize, Brazil, the Central Andes, and the Southern Cone, each dating to at least ∼9,000 years ago. The common ancestral population radiated rapidly from just one of the two early branches that contributed to Native Americans today. We document two previously unappreciated streams of gene flow between North and South America. One affected the Central Andes by ∼4,200 years ago, while the other explains an affinity between the oldest North American genome associated with the Clovis culture and the oldest Central and South Americans from Chile, Brazil, and Belize. However, this was not the primary source for later South Americans, as the other ancient individuals derive from lineages without specific affinity to the Clovis-associated genome, suggesting a population replacement that began at least 9,000 years ago and was followed by substantial population continuity in multiple regions.

No abstract

No abstract

The timing, structure, and landscape change during the Patagonian Ice Sheet deglaciation remains unresolved. In this article, we provide a geomorphic, stratigraphic, and geochronological deglacial record of Río Cisnes Glacier at 44°S and also from the nearby Río Ñirehuao and Río El Toqui valleys (45°S) in Chilean Patagonia. Our 14C, 10Be, and optically stimulated luminescence data indicate that after the last glacial maximum, Río Cisnes Glacier experienced ~100 km deglaciation between >19.0 and 12.3 ka, accompanied by the formation of large glacial paleolakes. Deglaciation was interrupted by several ice readvances, and by 16.9±0.3 ka, Río Cisnes Glacier extended only ~40% of its full glacial extent. The deglaciation of Río Cisnes Glacier and other sensitive Patagonian glaciers occurred at least 1 ka earlier than the ca. 17.8 ka normally assumed for the local termination, coincident with West Antarctic isotope records. This early deglaciation can be linked to an orbital forcing–driven decline of Southern Ocean sea ice associated with a distinct atmospheric warming that is apparent for West Antarctica through Patagonia.

This work aims to build a comprehensive isotopic ecology with the ultimate purpose of assessing long‐term human diet decision‐making by means of stable isotope analysis. We present a set of δ13Ccollagen and δ15Ncollagen isotopic values on the main faunal resources from the forest and steppe areas of the Aisén region (Central‐Western Patagonia, Chile), in order to characterise their isotopic ranges and assess their consumption by past hunter–gatherer populations. Two sets of bioarchaeological remains are used for this comparison; a 10 200–9700 cal year bp assemblage from Baño Nuevo cave and a 1600–300 cal year bp assemblage gathered at different locations throughout Aisén. Isotopic signals from both assemblages indicate diets based on the consumption of protein provided by terrestrial mammals from steppe environments and no long‐term signature of forest‐resource consumption. On the other hand, the earlier group shows values that may indicate a wider dietary breadth, although this observation is preliminary. These results further suggest that the use of forests and the resources they provided, although visible through the zooarchaeological record (i.e. taxa represented at sites), must have been discontinuous and, perhaps, marginal in comparison with steppe regions. Copyright © 2013 John Wiley & Sons, Ltd.