Phenotypic diversity and history of the Congo Basin populations: Equatorial Guinea, Bantu Speaking Central Africans and African Pygmies.

BACKGROUND: African Pygmy Populations (APP) are believed to be one of the first groups of the Congo Basin rainforest peoples to separate from the rest of modern humanity. The arrival of Bantu speaking agriculturalists from 5,000 BP led to the formation of a large number of ethnic complexes in Central Africa and the Atlantic coastal area, mainly due to a one-way flow of pygmy women. There are now only a few small contingents of African Pygmy population groups who are mixed or who have almost disappeared as a result of migratory flows from Cameroon. AIMS: We analysed the adult phenotypic diversity of 9 populations (17 groups of both sexes) of the Congo basin and Bioko Island, which were anthropometrically characterised in 1948. The phenotypic clusters that we detected, which we interpret as likely mixing of local Pygmy populations and Bantus, may be useful as references for future studies, particularly genetics. SUBJECTS AND METHODS: The matrix of inter-distances between populations was generated, using the 21 variables, with the Euclidean distance between the mean vectors relating to the standardised variables. When the UPGMA (Unweighted Pair Group Method with Arithmetic Mean) was used separately in men and women, the phylogenetic trees showed a clear separation between populations. RESULTS: The body measurements that most effectively distinguished the groups are linear dimensions and the width of the hips and mean thoracic circumference. In this study, the cephalo-facial dimensions were of little value in identifying the groups. CONCLUSIONS: The samples of Equatorial Guinea show a major inter-group overlap, and considerable intra-group variations. There are also notable differences amongst African Pygmy populations in terms of height, but not in body proportions.

Application of the recent SanMillán-Rissech acetabular adult aging method in a North American sample.

Recently, a renewed acetabular aging methodology was published by San-Millán et al. (Int J Leg Medicine, 47, 131: 501-525), refining the variables associated with acetabular fossa aging in different populations. Due to its novelty, this method has not yet been examined in any other population, other than it was developed and originally tested on. Therefore, the main goals of this study are two-fold: (1) to evaluate the accuracy of SanMillán-Rissech's method in a North American sample made up of 826 white (456 males and 370 females) individuals from the Bass Collection and (2) to determine whether the revised methodology shows higher rates of accuracy than the original methodology (J Forensic Sci, 31, 51(2): 213-229). Scores obtained by both methodologies were analyzed via a Bayesian statistical program (IDADE2) that estimates a relative likelihood distribution for the target individuals, produces age-at-death estimates, and provides 95% confidence intervals. Even though the revised method was developed using a Western European collection, the results demonstrate that it is also applicable to North American samples with reasonable accuracy results, i.e., an average absolute error of 7.19 years in males and 9.65 years in females. However, accuracy in females is significantly lower than in males, likely due to their higher morphological variability associated with different factors other than age. The significantly better performance of the revised methodology compared with the original is also been confirmed by the current findings from this North American sample, supporting the renewed system as a better aging methodology. Although work on further populations is needed, previously and current results should encourage professionals to include the acetabular method in forensic and archaeological laboratories routines.

Quantitative discrimination of deformation in Fueguian crania.

OBJECTIVES: Artificial deformation of the cranium in humans has been related to powerful environmental-cultural stimuli that modify vectors of growth and development when the cranium is still malleable. Osteological differentiation into deformed and nondeformed remains enables the morphological information of individuals that make up ethnic groups or populations to be separately contrasted, the invariant measurements of deformation to be identified, the information provided by archeological remains to be placed in a social context, the cranial variation to be related to genetic variation (individuals without deformation), and predictions to be made (in the absence of direct genetic information). METHODS: With samples of reduced size and many variables, we propose a decision rule based on: (a) pre-selecting variables (Kruskal-Wallis and Λ-Wilks test); (b) applying logistic regression to obtain the optimal classification criterion; and (c) defining a multi-criterion decision rule to bring about greater robustness. RESULTS: After applying the decision rule to a sample of 180 crania (71 from the Selknam, 74 from the Yamana, and 35 from the Alakaluf ethnic groups), it was possible to identify the Selknam men with frontal deformation and the Yamana women with flattening of the parietal regions at the height of the bregma. CONCLUSIONS: From there on with the information provided by the graphical representation of the populations in the most informative dimensions and the homogeneity contrast between sexes, we related the frontal deformation in Selknam men to dragging firewood, vegetable matter, domestic utensils, and heavy pieces of meat from the hunt. On the other hand, the flattening of the parietal areas at the height of the bregma in Yamana women is related to loading and transporting vegetables and animals in baskets or leather sacks.

Shape variability of the adult human acetabulum and acetabular fossa related to sex and age by geometric morphometrics. Implications for adult age estimation.

This study aims to explore shape variability of the acetabulum during the human adult life span, in relation to sex and age. The human acetabular shape was analysed in 682 os coxae from three different documented skeletal collections from the Iberian Peninsula. Two landmarks and thirty-two sliding semi-landmarks were used for the geometric morphometric procedures and a clock-wise standard was used for orientation. The 180° meridian (6:00) line was positioned over the midpoint of the acetabular notch and 36 reference points in 10° increments along the rim were marked. Data showed that size, sex and age significantly influence acetabular shape variation. Sex differences were significant in individuals younger than 65 years old and were characterised by males exhibiting relatively extended acetabular rim profiles from 10:00 to 1:00, narrower acetabular notches, and reduced acetabular fossae. In addition, three main age-related changes occurred to the acetabular shape in both sexes: outer acetabular profile modification, with extension from 10:00 to 1:00 and reduction from 7:00 to 9:00, acetabular notch narrowing, and acetabular fossa reduction. The age-related changes that were observed are shared by both sexes and seem to be related to bone production associated with age. Specifically, age appears to affect the entire border of the lunate surface: the acetabular rim, both acetabular horns, and the outer edge of the acetabular fossa. Furthermore, shape data confirmed the clover-leaf shape of the acetabular fossa in both males and females. These results improve our understanding of acetabular shape, and assist in refining age-estimation methods and enhancing hip surgery and rehabilitation.

New approach to age estimation of male and female adult skeletons based on the morphological characteristics of the acetabulum.

Age estimation is essential to the human identification process, both in forensic and archeological contexts. Based on the previous male-specific method of Rissech et al. (J Forensic Sci, 2006, 51:213-229), a new approach to age estimation based on the acetabulum has been described and evaluated in 611 individuals from the Lisbon Collection (Lisbon, Portugal). This paper has two main goals: (1) to revise and better define the variables of Rissech's method related to the acetabular fossa, namely, variables 5, 6, and 7, and (2) to extend the applicability of this new approach to both sexes while analyzing age-related sex differences in the acetabular aging process. The results demonstrate the suitability of combining acetabulum traits and a Bayesian approach to estimating age in adults of both sexes. This study has confirmed the usefulness of the redefined variables of the acetabular fossa when age-related changes are considered. Furthermore, the newly defined variables have good to excellent values of repeatability. The study has also extended the method's applicability to females. The revised method has absolute error averages of 7.28 years for males and 7.09 years for females, based on a sex-specific reference sample. In addition, approximately 74 % of the individuals estimated had an absolute error less than 10 years. Interestingly, the acetabular aging process follows similar trends in both sexes, but the aging rate seems to be different between males and females, especially in middle-aged individuals. Despite the fact that the age estimates, on average, did not improve significantly with the use of a sex-specific reference sample, it is recommended that the sexes be analyzed separately due to the differences in aging rates and inaccuracy values.

Ontogeny of the male femur: Geometric morphometric analysis applied to a contemporary Spanish population.

OBJECTIVE: To describe the morphological changes of the male femur during the adolescent growth spurt and to compare the pattern obtained with that reported previously for females. MATERIAL AND METHODS: Two hundred and forty males from a Spanish population aged between 9 and 16 years were analysed, based on telemetries. Size and shape variation of the femur was quantified by 22 2D-landmarks and analysed using geometric morphometric methods. Likewise, the variation of neck-shaft and bicondylar angles were also determined and evaluated by Student's t-test. Sexual differences were analysed by comparing results here obtained on boys with those corresponding to girls reported in a previous study. RESULTS: In males, both size and shape varied significantly with age, with males having larger dimensions than females. In general terms, these changes are generally characterised by an increase in robustness of the femur and shape modifications in the epiphyses. During growth, the neck-shaft angle decreases and the size of the greater and lesser trochanters increase. A significant increase of distal epiphyseal dimensions was recorded, mainly in the medial condyle. The angular remodeling of both the neck and the bicondylar regions of the male femur continues until 16 and 15 years, respectively. Female and male femur each followed divergent growth trajectories. Males showed a greater variability in neck-shaft and bicondylar angles than females. DISCUSSION: The timing, morphology and growth trajectories provided on the femur during development can be very helpful in anthropological, paleoanthropological and evolution studies.

A geometric morphometric analysis of acetabular shape of the primate hip joint in relation to locomotor behaviour.

The description of acetabular shape variation among primates is essential for our understanding of the locomotor behaviour and ecology of both extant and fossil species. In this study, we use two-dimensional geometric morphometrics to examine variation in acetabular shape in human and non-human primates and to determine the degree to which it co-varies with locomotor behaviour, while taking both intra and inter-specific variation into account. To these ends, we examined the acetabulum of 303 left hip bones of 27 extant genera of primates (including humans) with different locomotor behaviours. After accounting for shape variation due to sex, size, and phylogeny, the results confirm that acetabular shape varies significantly across locomotor groups. The two most differentiated locomotor groups are leapers and slow-climbing quadrupeds, which exhibit a unique acetabular shape. Furthermore, the acetabulum of humans differed significantly from all other groups, while no significant differences existed between chimpanzees and gorillas. The most noticeable differences are detected in both cranial and dorsal areas and around the acetabular horns. This variation in acetabular morphology may have biomechanical implications at the level of the hip joint, potentially determining joint range motion and load distribution during locomotion. Given the increasing number of published studies on fossil pelves, our results are widely applicable to fossil analyses, with critical implications for paleoanthropological analyses about the complex locomotor behaviour of fossil specimens and their classification into locomotor groups, which may enhance our understanding of their ecological habits.

Sexual dimorphism of the clavicle in a modern Spanish sample

The main objective of this study is to analyze the sexual dimorphism of the Spanish clavicle taking into account lateral asymmetry. A total of 77 adult individuals (45 males and 32 females) from the documented collection of Madrid were used. Twelve measurements were taken: four direct measurements on bone (Maximum length, midshaft circumference, sternal epiphyseal width, acromial epiphyseal width) and eight indirect measurements based on orthogonal photographic images of the clavicles placed on a light box (maximum depth of the lateral and medial curvature, angle of the lateral and medial curvature, lateral and medial curvature, area and perimeter). The asymmetry and sexual dimorphism were analyzed using Student’s t-test. Posteriorly, a PCA was applied to evaluate the contribution of each variable to sexual dimorphism. Finally, and taking into account previous results, a discriminant analysis was carried out on each clavicular side. Results indicate that the variables that contribute most in sexual dimorphism were five: perimeter, area, maximum length, midshaft circumference, and medial curvature. With them, fifteen formulae for each clavicular side were obtained: five by using individual variables and ten using combinations of two variables. The functions with highest accuracy were those constituted by two variables, specifically those comprising the midshaft circumference and the medial curvature. The obtained results and derived functions are important as they are the first to be obtained using Spanish clavicles to diagnose sex taking into account asymmetry. The new formulae are especially useful for skeletal remains from the Mediterranean area and in particular from the Iberian Peninsula

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Sex prediction from the femur and hip bone using a sample of CT images from a Spanish population.

Sex estimation and the analysis of sexual dimorphism is an essential part of forensic and archaeological studies of skeletons. However, osteologists often have to rely on single measurements, such as femoral head diameters, to estimate sex, especially when skeletons are incomplete. We have obtained a sex-prediction model based on CT images by applying the logistic regression technique to the measurements obtained for the proximal femoral epiphyses and coxal. Nine variables for 114 Spaniards (58 females and 56 males) of known age and sex from a region close to Madrid have been studied. The prediction equation obtained using these nine variables correctly classifies 99.1 % of these individuals. Reducing the equation to the three most explanatory variables (VDH, HDH and MIB) resulted in the correct classification of 98.3 %. These findings suggest that this procedure is highly effective for sex prediction. However, a lack of expertise may produce biases in the measurements obtained from CT images. Moreover, these equations are only most effective for the population for which they were calculated as human growth and body size are sensitive to nutritional variations, environmental stress and the so-called secular trend.

Ontogeny of the female femur: geometric morphometric analysis applied on current living individuals of a Spanish population.

In this study we describe the development of the female femur based on the analysis of high-resolution radiographic images by means of geometric morphometrics, while assessing the usefulness of this method in these kinds of studies. The material analysed consisted of digital images in DICOM format (telemetries), corresponding to 184 left femora in anterior view, obtained from the database of the Hospital Sant Joan de Déu of Barcelona (Spain). Bones analysed corresponded to individuals from 9 to 14 years old. Size and shape variation of the entire femur was quantified by 22 two-dimensional landmarks. Landmark digitisation errors were assessed using Procrustes anova test. Centroid size (CS) variation with age was evaluated by an anova test. Shape variation was assessed by principal component analysis. A mancova test between the first five principal components and age, using the CS as covariable, was applied. Results indicated that both size and shape vary significantly with age. Several age-related shape changes remained significant after removing the allometric effect. In general, an increase in the robustness of the bone and noticeable phenotypic changes in certain areas of the femur were observed. During growth in the proximal region of the femur, the collo-diaphyseal angle decreases, the neck of the femur widens and the fovea moves to a lower position, standing more in line with the plane of the neck. Likewise, the size of the greater and lesser trochanters increase. In the distal region, a significant increase of epiphyseal dimensions was recorded, mainly in the medial condyle. The angular remodelling of the neck and the bicondylar region of the femur in females continues until 13 years old. The information provided in the present study increases our knowledge on the timing and morphology of the femur during development, and in particular the morphology of the different femoral ossification centres during development.

Ancient DNA analysis of 8000 B.C. near eastern farmers supports an early neolithic pioneer maritime colonization of Mainland Europe through Cyprus and the Aegean Islands.

The genetic impact associated to the Neolithic spread in Europe has been widely debated over the last 20 years. Within this context, ancient DNA studies have provided a more reliable picture by directly analyzing the protagonist populations at different regions in Europe. However, the lack of available data from the original Near Eastern farmers has limited the achieved conclusions, preventing the formulation of continental models of Neolithic expansion. Here we address this issue by presenting mitochondrial DNA data of the original Near-Eastern Neolithic communities with the aim of providing the adequate background for the interpretation of Neolithic genetic data from European samples. Sixty-three skeletons from the Pre Pottery Neolithic B (PPNB) sites of Tell Halula, Tell Ramad and Dja'de El Mughara dating between 8,700-6,600 cal. B.C. were analyzed, and 15 validated mitochondrial DNA profiles were recovered. In order to estimate the demographic contribution of the first farmers to both Central European and Western Mediterranean Neolithic cultures, haplotype and haplogroup diversities in the PPNB sample were compared using phylogeographic and population genetic analyses to available ancient DNA data from human remains belonging to the Linearbandkeramik-Alföldi Vonaldiszes Kerámia and Cardial/Epicardial cultures. We also searched for possible signatures of the original Neolithic expansion over the modern Near Eastern and South European genetic pools, and tried to infer possible routes of expansion by comparing the obtained results to a database of 60 modern populations from both regions. Comparisons performed among the 3 ancient datasets allowed us to identify K and N-derived mitochondrial DNA haplogroups as potential markers of the Neolithic expansion, whose genetic signature would have reached both the Iberian coasts and the Central European plain. Moreover, the observed genetic affinities between the PPNB samples and the modern populations of Cyprus and Crete seem to suggest that the Neolithic was first introduced into Europe through pioneer seafaring colonization.

Continent-wide decoupling of Y-chromosomal genetic variation from language and geography in native South Americans.

Numerous studies of human populations in Europe and Asia have revealed a concordance between their extant genetic structure and the prevailing regional pattern of geography and language. For native South Americans, however, such evidence has been lacking so far. Therefore, we examined the relationship between Y-chromosomal genotype on the one hand, and male geographic origin and linguistic affiliation on the other, in the largest study of South American natives to date in terms of sampled individuals and populations. A total of 1,011 individuals, representing 50 tribal populations from 81 settlements, were genotyped for up to 17 short tandem repeat (STR) markers and 16 single nucleotide polymorphisms (Y-SNPs), the latter resolving phylogenetic lineages Q and C. Virtually no structure became apparent for the extant Y-chromosomal genetic variation of South American males that could sensibly be related to their inter-tribal geographic and linguistic relationships. This continent-wide decoupling is consistent with a rapid peopling of the continent followed by long periods of isolation in small groups. Furthermore, for the first time, we identified a distinct geographical cluster of Y-SNP lineages C-M217 (C3*) in South America. Such haplotypes are virtually absent from North and Central America, but occur at high frequency in Asia. Together with the locally confined Y-STR autocorrelation observed in our study as a whole, the available data therefore suggest a late introduction of C3* into South America no more than 6,000 years ago, perhaps via coastal or trans-Pacific routes. Extensive simulations revealed that the observed lack of haplogroup C3* among extant North and Central American natives is only compatible with low levels of migration between the ancestor populations of C3* carriers and non-carriers. In summary, our data highlight the fact that a pronounced correlation between genetic and geographic/cultural structure can only be expected under very specific conditions, most of which are likely not to have been met by the ancestors of native South Americans.

A collation of recently published Western European formulae for age estimation of subadult skeletal remains: recommendations for forensic anthropology and osteoarchaeology.

The aim of this study is to provide an effective and quick reference guide based on the most useful European formulae recently published for subadult age estimation. All of these formulae derive from studies on postnatal growth of the scapula, innominate, femur, and tibia, based on modern skeletal data (173 ♂, 173 ♀) from five documented collections from Spain, Portugal, and Britain. The formulae were calculated from Inverse Regression. For this reason, these formulae are especially useful for modern samples from Western Europe and in particular on 20th century human remains from the Iberian Peninsula. Eleven formulae were selected as the most useful because they can be applied to individuals from within a wide age range and in individuals of unknown sex. Due to their high reliability and because they derive from documented European skeletal samples, we recommend these formulae be used on individuals of Caucasoid ancestry from Western Europe.

Humeral development from neonatal period to skeletal maturity--application in age and sex assessment.

The goal of the present study is to examine cross-sectional information on the growth of the humerus based on the analysis of four measurements, namely, diaphyseal length, transversal diameter of the proximal (metaphyseal) end of the shaft, epicondylar breadth and vertical diameter of the head. This analysis was performed in 181 individuals (90 ♂ and 91 ♀) ranging from birth to 25 years of age and belonging to three documented Western European skeletal collections (Coimbra, Lisbon and St. Bride). After testing the homogeneity of the sample, the existence of sexual differences (Student's t- and Mann-Whitney U-test) and the growth of the variables (polynomial regression) were evaluated. The results showed the presence of sexual differences in epicondylar breadth above 20 years of age and vertical diameter of the head from 15 years of age, thus indicating that these two variables may be of use in determining sex from that age onward. The growth pattern of the variables showed a continuous increase and followed first- and second-degree polynomials. However, growth of the transversal diameter of the proximal end of the shaft followed a fourth-degree polynomial. Strong correlation coefficients were identified between humeral size and age for each of the four metric variables. These results indicate that any of the humeral measurements studied herein is likely to serve as a useful means of estimating sub-adult age in forensic samples.

Buccal dental microwear analyses support greater specialization in consumption of hard foodstuffs for Australopithecus anamensis.

Molar occlusal microwear texture and anisotropy analyses of 3 Australopithecus anamensis fossil specimens have shown complexity values similar to those of Au. afarensis, indicating that neither of these hominin species had a diet dominated by hard food. However, many researchers have suggested that these were some of the earliest hominins to have such diets. Here we examine buccal microwear patterns of 5 Au. anamensis, 26 Au. afarensis, 48 Hominoidea and 80 Cercopithecoidea primate specimens for independent evidence of dietary adaptations of Au. anamensis. The buccal microwear results obtained suggest that the diet of Au. anamensis relied heavily on hard, brittle food, at least seasonally. This is similar to the diet of the extant Cercopithecoidea primates, including Papio anubis and Chlorocebus aethiops, both of which live in wooded, seasonal savannah environments and have diets that include fruit and grasses, but also underground storage organs (USOs), such as corms or blades, as well as leaves and seeds, and also Mandrillus and Cercocebus, from forested environments with frugivorous-granivorous diets. Furthermore, the buccal microwear patterns of Au. anamensis and Au. afarensis clearly differed - in clear contrast to occlusal enamel texture observations-, which support previous dietary interpretations based on both anatomical and palaeocological reconstructions.

A comparison of three established age estimation methods on an adult Spanish sample.

Most current methods for adult skeletal age-at-death estimation are based on American samples comprising individuals of European and African ancestry. Our limited understanding of population variability hampers our efforts to apply these techniques to various skeletal populations around the world, especially in global forensic contexts. Further, documented skeletal samples are rare, limiting our ability to test our techniques. The objective of this paper is to test three pelvic macroscopic methods [(1) Suchey-Brooks; (2) Lovejoy; and (3) Buckberry and Chamberlain] on a documented modern Spanish sample. These methods were selected because they are popular among Spanish anthropologists and because they never have been tested in a Spanish sample. The study sample consists of 80 individuals (55 males and 25 females) of known sex and age from the Valladolid collection. Results indicate that in all three methods, levels of bias and inaccuracy increase with age. The Lovejoy method performs poorly (27%) compared with Suchey-Brooks (71%) and Buckberry and Chamberlain (86%). However, the levels of correlation between phases and chronological ages are low and comparable in the three methods (<0.395). The apparent accuracy of the Suchey-Brooks and Buckberry and Chamberlain methods is largely based on the broad width of the methods' estimated intervals. This study suggests that before systematic application of these three methodologies in Spanish populations, further statistical modeling and research into the covariance of chronological age with morphological change are necessary. Future methods should be developed specific to various world populations and should allow for both precision and flexibility in age estimation.

Postnatal ontogenesis of the tibia. Implications for age and sex estimation.

The growth of five variables of the tibia (diaphyseal length, diaphyseal length plus distal epiphysis, condylo-malleolar length, sagittal diameter of the proximal epiphysis, maximum breadth of the distal epiphysis) were analysed using polynomial regression in order to evaluate their significance and capacity for age and sex determination during and after growth. Data were collected from 181 (90♂ and 91♀) individuals ranging from birth to 25 years of age and belonging to three documented collections from Western Europe. Results indicate that all five variables exhibit linear behaviour during growth, which can be expressed by a first-degree polynomial function. Sexual significant differences were observed from age 15 onward in the two epiphysis measurements and condylo-malleolar length, suggesting that these three variables could be useful for sex determination in individuals older than 15 years. Strong correlation coefficients were identified between the five tibial variables and age. These results indicate that any of the studied tibial measurements is likely to serve as a useful source for estimating sub-adult age in both archaeological and forensic samples.

Y-chromosome haplotypes defined by 17 STRs included in AmpFlSTR Yfiler PCR Amplification Kit in a multi ethnical population from El Beni Department (North Bolivia).

Seventeen Y-STRs included in AmpFlSTR Yfiler PCR Amplification Kit (Applied Biosystems, USA) were studied in males from a multi ethnical population from El Beni Department (North Bolivia). Haplotypic and allelic frequencies were reported. Comparison of El Beni population with other samples from the region was carried out through Multidimensional Scalling over Rst distances matrix.

HUMTH01, HUMVWA31A, HUMCSF1PO and HUMTPOX polymorphisms in Amerindian populations living in the Beni department of Bolivia.

This report presents allele frequency and absolute genotype data of the short tandem repeat (STR) loci HUMTH01, HUMVWA31A, HUMCSF1PO and HUMTPOX for three autochthonous Amerindian populations living in the Beni Department of Bolivia. These related groups are the Quechua, Aymara and Beni populations all living in specific although sometimes overlapping areas that extend from the Andean habitat to the lowland Llanos de Moxos savannah passing through the Piedmont hills. The usefulness of these loci for paternity and identification testing was also examined. The present work completes previous genetic studies performed by the authors in these populations including mtDNA haplogroups (Bert et al., Hum Biol, 73:1-16, 2001) and HVRI data (Bert et al., Ann Hum Biol 31:9-28, 2004; Corella et al., Ann Hum Biol 34:34-35, 2007).

Mitochondrial DNA diversity of the Amerindian populations living in the Andean Piedmont of Bolivia: Chimane, Moseten, Aymara and Quechua.

BACKGROUND: Chimane, Moseten Aymara and Quechua are Amerindian populations living in the Bolivian Piedmont, a characteristic ecoregion between the eastern slope of the Andean mountains and the Amazonian Llanos de Moxos. In both neighbouring areas, dense and complex societies have developed over the centuries. The Piedmont area is especially interesting from a human peopling perspective since there is no clear evidence regarding the genetic influence and peculiarities of these populations. This land has been used extensively as a territory of economic and cultural exchange between the Andes and Amazonia, however Chimane and Moseten populations have been sufficiently isolated from their neighbour groups to be recognized as distinct populations. Genetic information suggests that evolutionary processes, such as genetic drift, natural selection and genetic admixture have formed the history of the Piedmont populations. AIM: The objective of this study is to characterize the genetic diversity of the Piedmont populations, analysing the sequence variability of the HVR-I control region in the mitochondrial DNA (mtDNA). Haplogroup mtDNA data available from the whole of Central and South America were utilized to determine the relationship of the Piedmont populations with other Amerindian populations. SUBJECT AND METHODS: Hair pulls were obtained in situ, and DNA from non-related individuals was extracted using a standard Chelex 100 method. A 401 bp DNA fragment of HVR-I region was amplified using standard procedures. Two independent 401 and 328 bp DNA fragments were sequenced separately for each sample. The sequence analyses included mismatch distribution and mean pairwise differences, median network analyses, AMOVA and principal component analyses. The genetic diversity of DNA sequences was measured and compared with other South Amerindian populations. RESULTS: The genetic diversity of 401 nucleotide mtDNA sequences, in the hypervariable Control Region, from positions 16 000-16 400, was characterized in a sample of 46 Amerindians living in the Piedmont area in the Beni Department of Bolivia. The results obtained indicate that the genetic diversity in the area is higher than that observed in other American groups living in much larger areas and despite the reduced size of the studied area the human groups analysed show high levels of inter-group variability. In addition, results show that Amerindian populations living in the Piedmont are genetically more related to those in the Andean than in the Amazonian populations.