How and when the Americas were populated remains contentious. Using ancient and modern genome-wide data, we find that the ancestors of all present-day Native Americans, including Athabascans and Amerindians, entered the Americas as a single migration wave from Siberia no earlier than 23 thousand years ago (KYA), and after no more than 8,000-year isolation period in Beringia. Following their arrival to the Americas, ancestral Native Americans diversified into two basal genetic branches around 13 KYA, one that is now dispersed across North and South America and the other is restricted to North America. Subsequent gene flow resulted in some Native Americans sharing ancestry with present-day East Asians (including Siberians) and, more distantly, Australo-Melanesians. Putative ‘Paleoamerican’ relict populations, including the historical Mexican Pericúes and South American Fuego-Patagonians, are not directly related to modern Australo-Melanesians as suggested by the Paleoamerican Model.

Native American population history is reexamined using a large data set of pre-Columbian mitochondrial genomes.

The emergence of complex cultural practices in simple huntergatherer groups poses interesting questions on what drives social complexity and what causes the emergence and disappearance of cultural innovations. Here we analyze the conditions that underlie the emergence of artificial mummification in the Chinchorro culture in the coastal Atacama Desert in northern Chile and southern Peru. We provide empirical and theoretical evidence that artificial mummification appeared during a period of increased coastal freshwater availability and marine productivity, which caused an increase in human population size and accelerated the emergence of cultural innovations, as predicted by recent models of cultural and technological evolution. Under a scenario of increasing population size and extreme aridity (with little or no decomposition of corpses) a simple demographic model shows that dead individuals may have become a significant part of the landscape, creating the conditions for the manipulation of the dead that led to the emergence of complex mortuary practices.climate variability | coastal desert | cultural evolution

The past two decades have seen a proliferation in bioarchaeological literature on the identification of scurvy, a disease caused by chronic vitamin C deficiency, in ancient human remains. This condition is one of the few nutritional deficiencies that can result in diagnostic osseous lesions. Scurvy is associated with low dietary diversity and its identification in human skeletal remains can provide important contextual information on subsistence strategy, resource allocation, and human‐environmental interactions in past populations. A large and robust methodological body of work on the paleopathology of scurvy exists. However, the diagnostic criteria for this disease employed by bioarchaeologists have not always been uniform. Here we draw from previous research on the skeletal manifestations of scurvy in adult and juvenile human skeletal remains and propose a weighted diagnostic system for its identification that takes into account the pathophysiology of the disease, soft tissue anatomy, and clinical research. Using a sample of individuals from the prehistoric Atacama Desert in Northern Chile, we also provide a practical example of how diagnostic value might be assigned to skeletal lesions of the disease that have not been previously described in the literature.

Summary There are many unanswered questions about the population history of the Central and South Central Andes, particularly regarding the impact of large-scale societies, such as the Moche, Wari, Tiwanaku, and Inca. We assembled genome-wide data on 89 individuals dating from ∼9,000-500 years ago (BP), with a particular focus on the period of the rise and fall of state societies. Today’s genetic structure began to develop by 5,800 BP, followed by bi-directional gene flow between the North and South Highlands, and between the Highlands and Coast. We detect minimal admixture among neighboring groups between ∼2,000–500 BP, although we do detect cosmopolitanism (people of diverse ancestries living side-by-side) in the heartlands of the Tiwanaku and Inca polities. We also highlight cases of long-range mobility connecting the Andes to Argentina and the Northwest Andes to the Amazon Basin. Video Abstract

Understanding how human societies interacted with environmental changes is a major goal of archaeology and other socio-natural sciences. In this paper, we assess the human-environment interactions in the Pampa del Tamarugal (PDT) basin of the Atacama Desert over the last 13,000 years. By relying on a socioenvironmental model that integrates ecosystem services with adaptive strategies, we review past climate changes, shifting environmental conditions, and the continuities and discontinuities in the nature and intensity of the human occupation of the PDT. As a result we highlight the importance of certain key resources such as water, an essential factor in the long-term trajectory of eco-historical change. Without water the outcome of human societies becomes hazardous.

Over one thousand prehistoric crania (n = 1,149) from northern Chile were analyzed to determine if the presence of external auditory exostosis (EAE) was a type of subsistence-induced pathology, a consequence of habitual fishing in the cold water of the Pacific Ocean, rather than genetically determined. To test this occupational hypothesis, the sample was divided according to chronology, type of economy, site elevation, and sex. The crania came from 43 sites, including the coast, lowland valleys (100-2,000 m), and highlands (2,000 to 4,000 m) with a time frame of 7,000 B.C. to the Inca era (1500 A.D.). There was a significant association between EAE, environment, and sex. The coastal inhabitants had the highest prevalence of EAE with 30.7% (103/336), followed by 2.3% (6/24) for the valley people and 0% (0/549) for highlanders. Coastal and valley men were significantly more affected than their female counterparts. Contrary to expectations, there was no significant association between EAE and economy and/or chronology. In the Arica area, the early Chinchorro fishers, without agriculture, had 27.7% (26/94) EAE, the subsequent agro-pastoralists, 42.7% (32/75), and the late Arican agro-pastoral fishers had 35.6% (36/101) EAE. Apparently, with the advent of agriculture, the coastal Arican populations increased their ocean harvests, rather than decreased them, to gain a surplus in order to trade with nonmaritime groups.

Este estudio aporta nuevos antecedentes empíricos, resultado de las excavaciones de cuatro campamentos de uso transitorio y dos entierros humanos, asociados a sitios con geoglifos, ubicados a lo largo de una ruta caravanera prehispánica de 150 km, que conectó a los oasis de Pica con la costa del océano Pacífico. Puesto que la mayoría de estos sitios se encuentra en territorios desérticos sin recursos, asociados a contextos tales como coprolitos de llamas y hojas de maíces, argumentamos que fueron componentes directos del tráfico caravanero. Esta ruta estuvo vinculada al intenso tráfico macrorregional de larga distancia por donde circulaban bienes económicos y suntuarios procedentes de los más diversos ambientes (selva-altiplano-oasis-pampacosta). Las seis dataciones de radiocarbono, obtenidas de los contextos excavados, indicarían que, si bien la mayoría de los geoglifos de la transecta de estudio fueron elaborados durante el período del Desarrollo Regional (900-1.450 años d.C.), ciertas rutas transdesérticas ya estaban en uso, al menos desde el Arcaico Tardío (1.300 años a.C.), por parte de cazadores, pescadores y recolectores. Palabras claves: geoglifos, caravanas de llamas, rutas de tráfico prehistórico, campamentos transitorios, dataciones absolutas. This study brings new empirical evidence, resulting from the excavation of four transitory camp sites and two human burials associated with geoglyphs, and found along a prehispanic caravan path of 150 km long, connecting the Pica oasis with the Pacific coastal ocean in the Atacama desert in northern Chile. Since the majority of these sites are found in resourceless desertic areas and are associated to contexts such as llama coprolites and corn leaves, we argue that these sites were direct components of caravan trafficking. This route was linked to an intensive long distance macro-regional traffic associated with the circulations of economic and sumptuary goods from diverse origins, including the selva, altiplano, oasis, pampa and coast. Radiocarbon dates obtained at the excavations indicate that even though most of the geoglyphs were created during the Desarrollo Regional period (900-1,450 yrs. A.D.) some transdesertic routes were already used, from at least the Late Archaic Period (1,300 B.C.) by hunters, fishers and gatherers.