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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.

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.

In this study, we report novel data on mitochondrial DNA in two of the largest eastern Bantu-speaking populations, the Shona from Zimbabwe and the Hutu from Rwanda. The goal is to evaluate the genetic relationships of these two ethnic groups with other Bantu-speaking populations. Moreover, by comparing our data with those from other Niger-Congo speaking populations, we aim to clarify some aspects of evolutionary and demographic processes accompanying the spread of Bantu languages in sub-Saharan Africa and to test if patterns of genetic variation fit with models of population expansion based on linguistic and archeological data. The results indicate that the Shona and Hutu are closely related to the other Bantu-speaking populations. However, there are some differences in haplogroup composition between the two populations, mainly due to different genetic contributions from neighboring populations. This result is confirmed by estimates of migration rates which show high levels of gene flow not only between pairs of Bantu-speaking populations, but also between Bantu and non-Bantu speakers. The observed pattern of genetic variability (high genetic homogeneity and high levels of gene flow) supports a linguistic model suggesting a gradual spread of Bantu-speakers, with strong interactions between the different lines of Bantu-speaker descent, and is also in agreement with recent archeological findings. In conclusion, our data emphasize the role that population admixture has played at different times and to varying degrees in the dispersal of Bantu languages. KEY WORDS genetic variability; mtDNA haplogroups; sub-Saharan Africa; Bantu speaker migrations

After the emancipation of African slaves in the Caribbean, the labor void left by out-migrating former slaves was filled by in-migrating indentured servants from prepartition India and China. In some areas of the Caribbean such as Trinidad, Suriname, and Guyana, the East-Indian migrants formed large communities. In this article, we report a study based on mtDNA and Ychromosomal markers of a small East-Indian community from Limon, Costa Rica. The purpose of the project is to determine the place of origin in the Indian subcontinent of the ancestors of our group and the contributions to its gene pool through gene flow by members of other ethnic groups. Both Y-chromosome and mtDNA suggest that the Indo-Costa Ricans descend from migrants primarily from Central India. While both paternal and maternal markers indicate that this group is overwhelmingly of Indian origin, they also indicate that males and females of African, European, and Amerindian origin contributed to it differently. We discuss our results in the historical context of the virtual extinction of Amerindian Caribbean groups, the forced migration of African slaves to the Caribbean, and the gene flow between Amerindians, Europeans, East-Indians, and Africans that eventually produced the Caribbean's currently diverse gene pool. Am J Phys Anthropol 134:175-189, 2007. KEY WORDS East-Indian diaspora; Costa Rica; gene flow

The concept of frame size has not undergone a thorough evaluation in non-Caucasian populations. Using data from the Central Asia High Altitude Population (CAHAP) study, we tested whether: (1) the relationship between frame size and body composition is different in high-, medium- and low-altitude populations; (2) elbow breadth is a better index of frame size than biacromial and biiliac breadth; and (3) measures of frame size are associated with blood pressure, cholesterol and triglycerides. A number of 334 male subjects aged 33 [+ or -] 10 years (mean [+ or -] standard deviation) were selected from the CAHAP population (n = 384) on the basis of the availability of breadth measurements. The subjects were 85 high-altitude Kirghizs, 105 medium-altitude Kazakhs, 79 low-altitude Kirghizs and 65 low-altitude Uighurs. A detailed anthropometric evaluation and blood pressure, cholesterol and trygliceride measurements were performed on all individuals. Among breadths, elbow had the lowest correlation with arm fat area, thigh fat area, calf fat area and the sum of trunk skinfolds (r [less than or equal to] 0.196, P < 0.01). Even if elbow breadth did not have the highest correlation with muscularity indexes, its constantly lower association with adiposity indexes shows that it is a better measure of frame size than biacromial breadth and biiliac breadth. The relationship between frame size and body composition did not differ in high-, medium- and low-altitude subjects (P = not significant, analysis of co-variance). Only a weak association was present between breadths, blood pressure, cholesterol and triglycerides (r [less than or equal to] 0.230, P < 0.01) and it was not influenced by altitude (P = not significant, analysis of co-variance). Elbow breadth was significantly correlated only with diastolic blood pressure (r = 0.121, P < 0.05). In conclusion: (1) the relationship between frame size and body composition is similar in high- and low-altitude populations; (2) elbow breadth is an index of frame size independent of altitude; and (3) elbow breadth is correlated with diastolic blood pressure, but this correlation is of doubtful biological relevance.

This article examines the effects of high altitude on body composition by investigating anthropometric and body composition variables of adult males in the Peruvian Andes. The Quechua subjects are shorter in relation to body weight and have lower presence of adiposity than do other ethnicities in the region, due to stresses of the high altitude environment.

To evaluate adaptive responses to high-altitude environment, we examined three groups of healthy adult males from Central Asia: 94 high-altitude (HA) Kirghiz subjects (3,200 m above sea level); 114 middle-altitude (MA) Kazakh subjects (2,100 m), and 90 low-altitude (LA) Kirghiz subjects (900 m). Data on chest size (chest perimeter and chest diameter), lung volume (forced expiratory volume (FEV) and forced expiratory volume in I sec (FEV1)), and hematological parameters (hemoglobin, erythrocytes, hematocrit, and SaO(sub 2)) are discussed. The results show that 1) chest shape is less flat in the samples living at higher altitude. In the HA sample, chest perimeter is lower but chest excursion is high. 2) In the highlanders, forced vital capacity (FVC) and FEV1 are no higher than in the other samples, even when corrected for stature and body weight. The negative correlation between FVC-FEV1 and age decreases with increasing altitude. 3) The HA and MA samples have higher values of hemoglobin, erythrocytes, and hematocrit. The HA sample has lower SaO(sub 2) and higher arterial oxygen content than the LA sample. No association between hematocrit and age was detected in the four samples. The results indicate that the high-altitude Kirghiz present features of developmental acclimatization to hypobaric hypoxia which are also strongly influenced by other major high-altitude environmental stresses. Keywords: hypoxia; adaptability; anthropometry; physiology; Kirghiz; Kazakhs

A sample of 141 Quechua-speaking individuals of the population of Tayacaja, in the Peruvian Central Andes, was typed for the following 16 genetic systems: ABO, Rh, MNSs, P, Duffy, AcP1, EsD, GLOI, PGM1, AK, 6-PGD, Hp, Gc, Pi, C3, and Bf. The genetic structure of the population was analyzed in relation to the allele frequencies available for other South Amerindian populations, using a combination of multivariate and multivariable techniques. Spatial autocorrelation analysis was performed independently for 13 alleles to identify patterns of gene flow in South America as a whole and in more specific geographic regions. We found a longitudinal cline for the AcP1*a and EsD*1 alleles which we interpreted as the result of an ancient longitudinal expansion of a putative ancestral population of modern Amerindians. Monmonnier's algorithm, used to identify areas of sharp genetic discontinuity, suggested a clear east-west differentiation of native South American populations, which was confirmed by analysis of the distribution of genetic distances. We suggest that this pattern of genetic structures is the consequence of the independent peopling of western and eastern South America or to low levels of gene flow between these regions, related to different environmental and demographic histories. Keywords: Andean populations; genetic differentiation; migration patterns; genetic boundaries

This study investigates the relationships among hematological variables, pulmonary function, and age in a sample of high-altitude natives. The following anthropometric and physiological variables were examined in 77 adult Quechua males from the Peruvian Central Andes (Huancavelica, 3,680 m): height, weight, sitting height, chest diameters, chest and abdominal circumferences, forced vital capacity (FVC), forced expiratory volume at I sec (FEV1), peak expiratory flow (PEF), hemoglobin concentration (Hb), red blood cells (RBC), hematocrit (Htc), diastolic and systolic blood pressure, body temperature, pulmonary rate, and pulse rate. The means of these variables for the Huancavelica sample fall within the range of variability previously observed in Andean populations. Principal components analysis and canonical correlation analysis suggest that in this native Andean population: 1) aging decreases lung function but does not affect hematological features, and 2) there is a negative age-independent correlation between lung function (FVC, FEV1, PEF) and hematological traits (Hb, RBC, Htc). Keywords: Andean natives; hemoglobin; lung function; anthropometry; principal component analysis

Sex-specific migration patterns have been revealed in four central Asian populations through analysis and comparisons of mtDNA and.Y-chromosome short tandem repeats. Females seems to have a higher migration rate. A male founder effect appears to exist in the settlement of high-altitude areas. Two lowland populations and two highland populations were sampled. Analysis of molecular variance (AMOVA) brought out a very great degree of genetic difference in the populations. For mtDNA, genetic diversity in the highlands is like that in the lowlands. Haplotype genetic diversity was much lower in high altitudes, especially in Kirghiz.

The origins of Central Asian populations are discussed as they relate to the mingling of genes along the Silk Road and to mtDNA control-region sequences found in peoples including the Kazakh, Uighurs, and both lowland and highland Kirhgiz. Peoples of Europe and eastern Asia have few mtDNA sequences in common, but central Asian peoples have sequences in common with both groups, but sequences found in the study covered here are different from sequences that Europeans and central Asians share, and altitude seems not to exert a major selective pressure in the populations studied.