Evaluating population histories in Patagonia and Tierra del Fuego, Chile, using ancient mitochondrial and Y-chromosomal DNA.

OBJECTIVES: This study aims to characterize the genetic histories of ancient hunter-gatherer groups in Fuego-Patagonia (Chile) with distinct Marine, Terrestrial, and Mixed Economy subsistence strategies. Mitochondrial (mtDNA) and Y-chromosome data were generated to test three hypotheses. H0: All individuals were drawn from the same panmictic population; H1: Terrestrial groups first populated the region and gave rise to highly specialized Marine groups by ~7,500 cal BP; or H2: Marine and Terrestrial groups represent distinct ancestral lineages who migrated independently into the region. METHODS: Ancient DNA was extracted from the teeth of 50 Fuegian-Patagonian individuals dating from 6,895 cal BP to after European arrival, and analyzed alongside other individuals from previous studies. Individuals were assigned to Marine, Terrestrial, and Mixed Economy groups based on archeological context and stable isotope diet inferences, and mtDNA (HVR1/2) and Y-chromosome variation was analyzed. RESULTS: Endogenous aDNA was obtained from 49/50 (98%) individuals. Haplotype diversities, FST comparisons, and exact tests of population differentiation showed that Marine groups were significantly different from Terrestrial groups based on mtDNA (p < 0.05). No statistically significant differences were found between Terrestrial and Mixed Economy groups. Demographic simulations support models in which Marine groups diverged from the others by ~14,000 cal BP. Y-chromosome results showed similar patterns but were not statistically significant due to small sample sizes and allelic dropout. DISCUSSION: These results support the hypothesis that Marine and Terrestrial economic groups represent distinct ancestral lineages who diverged during the time populations were expanding in the Americas, and may represent independent migrations into Fuego-Patagonia.

Early human dispersals within the Americas.

Studies of the peopling of the Americas have focused on the timing and number of initial migrations. Less attention has been paid to the subsequent spread of people within the Americas. We sequenced 15 ancient human genomes spanning from Alaska to Patagonia; six are ≥10,000 years old (up to ~18× coverage). All are most closely related to Native Americans, including those from an Ancient Beringian individual and two morphologically distinct "Paleoamericans." We found evidence of rapid dispersal and early diversification that included previously unknown groups as people moved south. This resulted in multiple independent, geographically uneven migrations, including one that provides clues of a Late Pleistocene Australasian genetic signal, as well as a later Mesoamerican-related expansion. These led to complex and dynamic population histories from North to South America.

Talla, peso e índice de masa corporal en niños y niñas wichí de Formosa, Argentina / Height, weight and body mass index of Wichí children from Formosa, Argentina

Este trabajo presenta datos antropométricos descriptivos de 194 niños y niñas (0-18 años) de una población wichí de la provincia de Formosa, Argentina. El objetivo fue documentar el crecimiento y el estado nutricional de este pueblo originario. Se tomaron datos de peso, talla e índice de masa corporal y se calcularon los respectivos puntajes Z utilizando referencias nacionales e internacionales. La mayoría de los parámetros analizados caen dentro de los rangos de la normalidad. Sin embargo, es preocupante la presencia de un porcentaje significativo de niñas y niños con sobrepeso, lo cual indicaría que esta población se encuentra atravesando un proceso de occidentalización que promueve el consumo de alimentos procesados hipercalóricos y una menor actividad física.

This study provides the descriptive, anthropometric data of 194 children (aged 0-18 years) from a Wichi population located in the province of Formosa, Argentina. The objective of this study was to document growth and nutritional status in this indigenous people. Weight, height, and body mass index data were collected and the corresponding Z-scores were estimated using national and international reference standards. Most analyzed parameters were within the normal range. However, it is concerning that a significant percentage of children are overweight, which may indicate that this population is going through a process of westernization that promotes the consumption of high-calorie, highly-processed foods and a lower level of physical activity.

Height, weight and body mass index of Wichí children from Formosa, Argentina. / Talla, peso e índice de masa corporal en niños y niñas wichí de Formosa, Argentina.

This study provides the descriptive, anthropometric data of 194 children (aged 0-18 years) from a Wichi population located in the province of Formosa, Argentina. The objective of this study was to document growth and nutritional status in this indigenous people. Weight, height, and body mass index data were collected and the corresponding Z-scores were estimated using national and international reference standards. Most analyzed parameters were within the normal range. However, it is concerning that a significant percentage of children are overweight, which may indicate that this population is going through a process of westernization that promotes the consumption of high-calorie, highly-processed foods and a lower level of physical activity.

Este trabajo presenta datos antropométricos descriptivos de 194 niños y niñas (0-18 años) de una población wichí de la provincia de Formosa, Argentina. El objetivo fue documentar el crecimiento y el estado nutricional de este pueblo originario. Se tomaron datos de peso, talla e índice de masa corporal y se calcularon los respectivos puntajes Z utilizando referencias nacionales e internacionales. La mayoría de los parámetros analizados caen dentro de los rangos de la normalidad. Sin embargo, es preocupante la presencia de un porcentaje significativo de niñas y niños con sobrepeso, lo cual indicaría que esta población se encuentra atravesando un proceso de occidentalización que promueve el consumo de alimentos procesados hipercalóricos y una menor actividad física.

Maize (Zea mays) consumption in the southern andes (30°-31° S. Lat): Stable isotope evidence (2000 BCE-1540 CE).

OBJECTIVES: The timing and dietary role of maize agriculture is central to archaeological discussions in the Andean region. In the semi-arid region of northern Chile (SARNC), archaeological models propose that maize was adopted during the Early Ceramic period in tandem with pottery and sedentism. Through stable isotope (SI) analyses, of bone collagen and apatite, this study assesses the timing of maize introduction, diachronic changes (2,000 BCE to 1,540 CE.), and synchronic dietary variability in the prehistoric SARNC. MATERIALS AND METHODS: Fifty-two prehistoric individuals from SARNC were analyzed for δ13 Cap , δ13 Ccol, and δ15 N. Descriptive statistics were used to characterize the results by period and location (inland and coast). Between-periods (ANOVA or Kruskal-Wallis tests), and synchronic comparisons (inland vs. coast; Student's t-tests), were conducted. A SIAR model was run to further evaluate dietary changes. Dietary interpretations are based on food web data. RESULTS: Coastal groups show significant changes in the diet during the Middle (900-1,000CE; enrichment in δ13 C), and Late Intermediate periods (100-1450CE; when the Δ13 Cap-col is above 5.2‰). In the inland, significant changes in SI occurred in the Late Intermediate period (δ13 C enrichment). In the Late period, the inland diet became enriched for δ15 N. Synchronic comparisons showed coastal individuals to have higher δ15 N. DISCUSSION: The popularization of maize in the SARNC was not associated with the appearance of pottery and/or sedentism, and its role as a dietary staple was a late phenomenon (c.a. 1,000CE). The results obtained in this study show that the adoption and consumption of maize varied dramatically in the Southern Andes.

Growth patterns among indigenous Qom children of the Argentine Gran Chaco.

OBJECTIVES: This study describes and compares the growth strategies of rural (Western) and peri-urban (Eastern) Qom indigenous children from Argentina. METHODS: Height and weight were cross-sectionally assessed in Western (n = 263) and Eastern Qom (n = 512) individuals aged 0-18.9 years. Height-for-age (HAZ), weight-for-age (WAZ), and BMI-for-age (BMIZ) z-scores were calculated with an LMS software. Results were organized into four age categories: infancy, childhood, juvenility, and adolescence. Between-group comparisons of HAZ, WAZ, and BMIZ were carried out by age and sex categories and compared with Student's t or Mann Whitney tests. Nutritional status was classified based on BMIZ following WHO recommendations and was compared with x2 tests. RESULTS: In both groups, height and weight followed the typical human growth curve. Mean HAZ scores in both groups were within two standard deviations from the international reference, and increased from infancy to juvenility. WAZ and BMIZ scores were high during infancy and showed a general declining trend with age. Overall, Western Qom had higher HAZ scores. WAZ and BMIZ score comparisons showed only a handful of statistically significant differences, which, along with the analysis of BMI categories, indicated an association between peri-urban environments and a higher prevalence of overweight and obese individuals (P < 0.01). CONCLUSION: Among the Qom, low HAZ and high WAZ scores during the early years of development allow for the attainment of a relatively high adult stature. Their adaptive life-history strategy seems to be to divert energy toward body mass during early development, and catch-up with linear growth at a later stage of development. Am. J. Hum. Biol. 28:895-904, 2016. © 2016Wiley Periodicals, Inc.

Experimental assessment of nutrition and bone growth's velocity effects on Harris lines formation.

Harris lines (HL) are radio-opaque transverse lines traditionally associated with stressors that halt or decelerate growth in humans. Harris lines' status as a stress marker is, however, questionable because their association to illness and deficient growth is low and they commonly form in the absence of stress during periods of accelerated growth. To assess Harris line's reliability as a stress marker, this study examined their association with nutritional status and bone growth velocity through an experimental study in rabbits. Forty-five New Zealand White rabbits were divided into: Control (normal laboratory conditions), Experimental-1 (moderately undernourished), and Experimental-2 (periodically fasted) groups during their growth. Variables analyzed included weight, forelimb length, humeral diaphyseal length, diaphyseal growth velocity, and number of Harris lines. Fewer lines were observed by the end of the study among Experimental-1 animals. More Harris lines formed during periods of rapid growth in the absence of nutritional stress. Accordingly, Harris lines are a poor marker of stress. Intrinsic limitations to paleopathological studies can be overcome, but even the most careful attentiveness to multiple stress markers and cultural context will go amiss if the markers used are unreliable.