POPULATION GENETICS. Genomic evidence for the Pleistocene and recent population history of Native Americans

How and when the Americas were populated remains contentious. Using ancient and modern genome-wide data, we found 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 (ka) and after no more than an 8000-year isolation period in Beringia. After their arrival to the Americas, ancestral Native Americans diversified into two basal genetic branches around 13 ka, one that is now dispersed across North and South America and the other 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.

Characterization of dental fillings found in skulls from individuals buried in San Jeronimos Church, New Spain: historical and archaeological evidences

Repair of teeth during the XIX century was often a very costly and painful procedure. During this period, restoration of teeth was a procedure limited only to those who could afford such care. In this study we analyzed teeth from a skull sample found in San Jeronimo's Church. The characterization of molar fillings was made with techniques such as X-ray fluorescence, X-ray diffraction and electron microscopy. The purpose of this investigation was to establish technical procedures for analysis, and to discuss the results within the context of the socioeconomic status of these individuals and the written descriptions of the dental practice during the XIX century.

Osteopoikilosis in an ancient skeleton: more than a medical curiosity

We describe the palaeopathologic and radiographic findings of the human skeletal remains that belonged to a female who lived in Mexico's viceroyship period (seventeenth and eighteenth centuries A.D.). Radiographic studies showed numerous, radiodense, ovoid, small and well-defined foci in the long tubular bones, sacrum, scapulae and iliac bones. Computed tomography (CT) examination revealed multiple hyperdense foci located in the central marrow portion of the bones. Measurements of attenuation coefficient revealed +1548 HU. The findings are consistent with osteopoikilosis, an uncommon, benign sclerosing bone dysplasia transmitted in an autosomal dominant fashion, which in the clinical setting is important to set apart from different bone pathologies to avoid unnecessary interventions and treatments. To the best of our knowledge, this is the first report of osteopoikilosis in ancient human remains.