MORPHOMETRIC AND mtDNA ANALYSES OF ARCHAIC SKELETAL REMAINS FROM SOUTHWESTERN SOUTH AMERICA (original) (raw)
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American Journal of Physical Anthropology, 2010
The cranial morphology of Early Holocene American human samples is characterized by a long and narrow cranial vault, whereas more recent samples exhibit a shorter and wider cranial vault. Two hypotheses have been proposed to account for the morphological differences between early and late-American samples: (a) the migratory hypothesis that suggests that the morphological variation between early and late American samples was the result of a variable number of migratory waves; and (b) the local diversification hypothesis, that is, the morphological differences between early and late American samples were mainly generated by local, random (genetic drift), and nonrandom factors (selection and phenotypic plasticity). We present the first craniometric study of three early skulls from the Argentinean Pampas, dated ∼8,000 cal. years BP (Arroyo Seco 2, Chocorí, and La Tigra), and one associated with mega-faunal remains (Fontezuelas skull). In addition, we studied several Late Holocene samples. We show that the skulls from the Argentinean Pampas are morphologically similar to other Early Holocene American skulls (i.e., Lagoa Santa from Brazil, Tequendama, Checua, and Aguazuque from Colombia, Lauricocha from Peru, and early Mexicans) that exhibit long and narrow cranial vaults. These samples differ from the Late Holocene American samples that exhibit a shorter and wider cranial vault. Our results underscore the important differences in cranial morphology between early and late-American samples. However, we emphasize the need for further studies to discuss alternative hypotheses regarding such differences. Am J Phys Anthropol 143:298–305, 2010. © 2010 Wiley-Liss, Inc.
Science 344, 750 (2014)
of the Proyecto Espeleológico de Tulum . HN is a bell-shaped chamber (the pit) located below the confluence of three horizontal passages with floors at ~12 mbsl . The pit is 37 m in diameter at its rim, expanding to 62 m at the boulder-strewn floor, which slopes from 33 mbsl on the north to ~48 m along the south wall. This geometry made it an inescapable natural trap ). HN contains layered fresh and saltwater, with the halocline lying at 15 to 22 mbsl. The freshwater lens is slightly acidic (pH 6.8) and cool (25.2°C), the saltwater is over 95% marine salinity, slightly basic (pH 7.1), and slightly warmer (25.5°C).
Ancient DNA Studies in Mesoamerica: Major Contributions and Limitations
Abstract (English) Ancient DNA is a method that many studies have applied in the last decade. Since 1984, the refinement of the method has been challenging due to contamination issues and difficulties for verification of results, although scientists have overcome such problems. In the last few years, the method has been used for answering question about the dynamics of prehispanic societies in Mesoamerica. The results of these studies have clarified internal social processes suggesting more specific ancestral origins for different ancient populations. Many variables limit the number of studies and the databases are still slowly developing. Here, I explore the major contributions of this method, its more recent technical improvements, and the main challenges that ancient DNA research is facing. Finally, I present the possibilities of this method for future Mesoamerican studies. Resumen (Spanish) El ADN antiguo es método se ha aplicado a varios estudios durante las últimas décadas. Desde 1984, el refinamiento del método ha sido desafiante debido a los problemas de contaminación y las dificultades para la verificación de resultados; sin embargo los investigadores han logrado encontrar soluciones para sobrellevar muchas de estas dificultades. En los últimos años, el estudio de ADN antiguo se ha utilizado para responder preguntas sobre las dinámicas de sociedades prehispánicas en Mesoamérica. Los resultados de estos estudios han arrojado luz sobre procesos sociales internos, y además han corroborado los orígenes de algunas de éstas poblaciones antiguas. Muchas variables limitan el número de estudios paleogenéticos y la construcción de una base de datos genética para la Mesoamérica prehispánica continúa desarrollándose aún lentamente. En este trabajo se presentan las mayores contribuciones del ADN antiguo al conocimiento de sociedades Mesoamericanas, así como las mas recientes soluciones y mejoras técnicas, y los mayores retos que aun enfrenta el ADN antiguo como herramienta de investigación para la arqueología. Finalmente, se presentan las futuras posibilidades para estudios paleogenéticos en Mesoamérica.
After several years of research, there is now a consensus that America was populated from Asia through Beringia, probably at the end of the Pleistocene. But many details such as the timing, route(s), and origin of the first settlers remain uncertain. In the last decade genetic evidence has taken on a major role in elucidating the peopling of the Americas. To study the early peopling of South America, we sequenced the control region of mitochondrial DNA from 300 individuals belonging to indigenous populations of Chile and Argentina, and also obtained seven complete mitochondrial DNA sequences. We identified two novel mtDNA monophyletic clades, preliminarily designated B2l and C1b13, which together with the recently described D1g sub-haplogroup have locally high frequencies and are basically restricted to populations from the extreme south of South America. The estimated ages of D1g and B2l, about ,15,000 years BP, together with their similar population dynamics and the high haplotype diversity shown by the networks, suggests that they probably appeared soon after the arrival of the first settlers and agrees with the dating of the earliest archaeological sites in South America (Monte Verde, Chile, 14,500 BP). One further sub-haplogroup, D4h3a5, appears to be restricted to Fuegian-Patagonian populations and reinforces our hypothesis of the continuity of the current Patagonian populations with the initial founders. Our results indicate that the extant native populations inhabiting South Chile and Argentina are a group which had a common origin, and suggest a population break between the extreme south of South America and the more northern part of the continent. Thus the early colonization process was not just an expansion from north to south, but also included movements across the Andes.
During most of the 19th and 20th centuries, the best accepted paradigm for the settlement of the New World suggested that all Native American populations, past and present, derived from only one biological population, coming from Northeast Asia. However, craniometric analyses of early South and Mesoamerican skulls questioned this model by showing that the oldest populations known in the New World did not share the same morphological pattern with late Amerindian groups. The morphological pattern of these early populations is now known as Paleoamerican, and has been found widespread across South and Meso America, in population samples as well as in isolated specimens. Here we analyze for the first time the morphological affinities of all known Early American skulls from South and Meso America. Morphological affinities were assessed through Principal Components Analysis, and two tests were carried out. In the first the Early Americans were separated according to their geographic region while in the second they were considered as one same population. The results confirm previous analyses done by Neves and collaborators, showing high morphological affinities among the Early Americans samples as well as between these and Autralo-Melanesian series. Late Amerindians always appear opposite from Early Americans in the morphospace. These results indicate that groups presenting the Paleoamerican morphology were widespread across South and Meso America, suggesting a relatively high population density, which facilitated gene flow among regional groups.
ANÁLISIS MORFOMÉTRICO Y DE ADNmt DE RESTOS ESQUELETALES ARCAICOS DEL SUROESTE DE SUDAMÉRICA
Chungará (Arica …, 2011
For decades anthropologists have discussed how and when the Americas were peopled. The prevailing view is that the first Paleoindians, ancestors of the Amerindians, arrived from Asia and Beringia to the American continent using a Pacific coastal route in pre-Clovis times. In this article skeletal remains dated 9000-4000 BP, excavated from archaeological sites in northern, central and southern Chile, were analyzed using geometric morphometric and ancient mtDNA techniques. Results indicate that the ancient cranial material from southwestern South America exhibit a wide range of cranial vault shape variation which is independent of chronology. mtDNA restriction and sequence analysis performed on the same skeletal remains, revealed only the presence of the main four founding mtDNA haplogroups (A, B, C and D) as early as 9,000 BP. Our results using morphometric and molecular mtDNA haplogroup data show that human populations inhabiting the Americas during archaic times can not be considered as belonging to two different groups on the basis of analyzed data. These results are consistent with those recently obtained using complete sequence mtDNA analyses.
First analysis of ancient mtDNA genetic diversity in Northern coast of Argentinean Patagonia
Journal of Archaeological Science: Reports, 2017
In the past decades, archaeological research advances in different Patagonian sectors have contributed to the knowledge of lifestyle and evolution of pre-Columbian populations in these regions. The San Matías Gulf archaeological record (Río Negro province, Northern Patagonia, Argentina) shows that humans occupied the area from Middle Holocene to contact period, where palaeodietary and technological changes are evident from around 1700 14 C BP. Nevertheless, few studies have been done on biological origin and evolution of these populations. For this reason and in order to investigate mitochondrial genetic variability in comparison with other ancient and contemporary Patagonian populations, we analyzed ancient DNA on human skeletal remains belonging to different chronologies of this area. We found a prevalence of founding lineages C1, D1 (D1g and D1j subclades) and D4h3a, low frequency of A2 and absence of B2. This supports the hypothesis of genetic drift acting on populations of the Southern Cone of South America. Individuals analyzed present similar haplotypes, indicating a possible temporal and regional continuity or a common population origin. Those lineages are also present in Tehuelche and Mapuche contemporary populations. However, B2 is highly represented in these extant groups possibly as a consequence of recent migrations related with Araucanization process.
PlosOne, 2020
The human settlement of the Americas has been a topic of intense debate for centuries, and there is still no consensus on the tempo and mode of early human dispersion across the continent. When trying to explain the biological diversity of early groups across North, Central and South America, studies have defended a wide range of dispersion models that tend to oversimplify the diversity observed across the continent. In this study, we aim to contribute to this debate by exploring the cranial morphological affinities of four late Pleistocene/early Holocene specimens recovered from the caves of Quintana Roo, Mexico. The four specimens are among the earliest human remains known in the continent and permit the contextualization of biological diversity present during the initial millennia of human presence in the Americas. The specimens were compared to worldwide reference series through geometric morphometric analyses of 3D anatomical landmarks. Morphological data were analyzed through ...