Ancient mitochondrial DNA provides high-resolution time scale of the peopling of the Americas.

The exact timing, route, and process of the initial peopling of the Americas remains uncertain despite much research. Archaeological evidence indicates the presence of humans as far as southern Chile by 14.6 thousand years ago (ka), shortly after the Pleistocene ice sheets blocking access from eastern Beringia began to retreat. Genetic estimates of the timing and route of entry have been constrained by the lack of suitable calibration points and low genetic diversity of Native Americans. We sequenced 92 whole mitochondrial genomes from pre-Columbian South American skeletons dating from 8.6 to 0.5 ka, allowing a detailed, temporally calibrated reconstruction of the peopling of the Americas in a Bayesian coalescent analysis. The data suggest that a small population entered the Americas via a coastal route around 16.0 ka, following previous isolation in eastern Beringia for ~2.4 to 9 thousand years after separation from eastern Siberian populations. Following a rapid movement throughout the Americas, limited gene flow in South America resulted in a marked phylogeographic structure of populations, which persisted through time. All of the ancient mitochondrial lineages detected in this study were absent from modern data sets, suggesting a high extinction rate. To investigate this further, we applied a novel principal components multiple logistic regression test to Bayesian serial coalescent simulations. The analysis supported a scenario in which European colonization caused a substantial loss of pre-Columbian lineages.

Archaeological, radiological, and biological evidence offer insight into Inca child sacrifice.

Examination of three frozen bodies, a 13-y-old girl and a girl and boy aged 4 to 5 y, separately entombed near the Andean summit of Volcán Llullaillaco, Argentina, sheds new light on human sacrifice as a central part of the Imperial Inca capacocha rite, described by chroniclers writing after the Spanish conquest. The high-resolution diachronic data presented here, obtained directly from scalp hair, implies escalating coca and alcohol ingestion in the lead-up to death. These data, combined with archaeological and radiological evidence, deepen our understanding of the circumstances and context of final placement on the mountain top. We argue that the individuals were treated differently according to their age, status, and ritual role. Finally, we relate our findings to questions of consent, coercion, and/or compliance, and the controversial issues of ideological justification and strategies of social control and political legitimation pursued by the expansionist Inca state before European contact.

Stable isotope and DNA evidence for ritual sequences in Inca child sacrifice.

Four recently discovered frozen child mummies from two of the highest peaks in the south central Andes now yield tantalizing evidence of the preparatory stages leading to Inca ritual killing as represented by the unique capacocha rite. Our interdisciplinary study examined hair from the mummies to obtain detailed genetic and diachronic isotopic information. This approach has allowed us to reconstruct aspects of individual identity and diet, make inferences concerning social background, and gain insight on the hitherto unknown processes by which victims were selected, elevated in social status, prepared for a high-altitude pilgrimage, and killed. Such direct information amplifies, yet also partly contrasts with, Spanish historical accounts.

Radiologic evaluation of the Llullaillaco mummies.

OBJECTIVE: Our purpose was to determine the imaging findings in three 500-year-old frozen mummies of sacrificial Inca children. MATERIALS AND METHODS: CT, conventional radiography, and dental radiography of Inca mummies were reviewed. Different techniques, which were adjusted to the anatomic position of the bodies, were used for radiologic analyses. Working sessions were limited to 20 min because of the fragility of these mummies and to prevent thawing of the specimens. RESULTS: Internal organs in good condition with a natural shrinkage caused by dehydration were shown on CT scans. Both white and gray matter were clearly observed in the brain and cerebellum. The white matter and the fatty tissue of the bodies were visibly white. This condition was possibly caused by the transformation of the fatty tissue into a waxlike substance and the deposition of calcium salts. The lungs were expanded in all three mummies. The ages of the three children at the time of their deaths were estimated by means of radiographs of the teeth and long bones. Bone mineralization, the muscular volume, and the thickness of the adipose panniculus indicated the good nutritional state of the three Inca children. The spleen was not visualized in any case. CONCLUSION: Radiology helped us determine the state of the internal organs, the nutritional conditions, and the physical abnormalities of the naturally mummified children. These mummies can be considered among the best preserved mummies currently known.