Dental pulp calcifications in prehistoric and historical skeletal remains.

BACKGROUND: The prevalence of hard tissue formations in the dental pulp varies considerably. Beside ageing processes and irritations of the dental pulp, etiological associations with cardiovascular disease and dietary habits have been discussed, which are of particular research interest. The aim of this pilot study is to provide new insights on structural and etiological factors involved in the development of pulp calcifications by investigating skeletal remains from different (pre)historic periods. METHODS: The jaws of 46 skeletons excavated in central Germany, were examined for the presence of pulp stones using digital volume tomography (DVT). A total of 1122 teeth were examined with all tooth types considered. To obtain information about the three-dimensional structure of pulp calcifications, micro-CT images were taken. Thin sections of three molars were histologically analysed. Potential dietary effects were studied by analysing stable isotope ratios of nitrogen (δ15N) in bone samples collected from each individual. RESULTS: The analysis indicates that pulp stones affect molars in particular and increase slightly with age and dental wear. The micro-CT scans and the histological analysis show that the structures are much more complex than presumed on the basis of DVT imaging. Individuals with lower δ15N-isotope values and thus with a potentially lower proportion of animal protein in their diet appear to be less affected by pulp stones. CONCLUSION: When comparing between archaeological and recent data, DVT analysis provides qualitatively comparable results. Micro-CT and histological images illustrate the excellent preservation of pulp calcifications and their complex structure. Differences in prevalence rates and δ15N-isotope values of Neolithic and historical individuals support the assumption that dietary habits and living conditions could have an influence on the development of pulp calcifications. Due to the small sample size these results require further validation.

Reconstructing Bronze Age diets and farming strategies at the early Bronze Age sites of La Bastida and Gatas (southeast Iberia) using stable isotope analysis.

The El Argar society of the Bronze Age in the southeast of the Iberian Peninsula (2200-1550 cal BCE) was among the first complex societies in Europe. Its economy was based on cereal cultivation and metallurgy, it was organized hierarchically, and successively expanded its territory. Most of the monumentally fortified settlements lay on steeply sloped mountains, separated by fertile plains, and allowed optimal control of the area. Here, we explore El Argar human diets, animal husbandry strategies, and food webs using stable carbon and nitrogen isotope analysis of charred cereal grains as well as human and animal bone collagen. The sample comprised 75 human individuals from the sites of La Bastida (n = 52) and Gatas (n = 23), 32 domesticated and wild animals as well as 76 barley and 29 wheat grains from two chronological phases of a total time span of ca. 650 years. The grains indicate extensive cereal cultivation under rain-fed conditions with little to moderate application of manure. Especially at La Bastida, crops and their by-products contributed significantly to the forage of the domesticated animals, which attests to a strong interrelation of cultivation and animal husbandry. Trophic level spacing and Bayesian modelling confirm that human diets were largely based on barley with some contribution of meat or dairy products. A cross-sectional analysis of bone collagen suggests that children were breastfed until about 1.5-2 years old, and infants from Gatas may have suffered from more metabolic stress than those at La Bastida. Adults of both sexes consumed similar diets that reflect social and chronological variation to some extent. Despite significantly higher δ13C and δ15N values at La Bastida than at Gatas, the isotopic data of the staple crops and domestic animals from both sites indicate that such differences do not necessarily correspond to different average human diets, but to agricultural strategies. These results urge for a reassessment of previous isotope studies in which only human remains have been taken into account. The study highlights that disentangling the complex influences on human isotope compositions requires a firm set of comparative data.

A massacre of early Neolithic farmers in the high Pyrenees at Els Trocs, Spain.

Violence seems deeply rooted in human nature and an endemic potential for such is today frequently associated with differing ethnic, religious or socio-economic backgrounds. Ethnic nepotism is believed to be one of the main causes of inter-group violence in multi-ethnic societies. At the site of Els Trocs in the Spanish Pyrenees, rivalling groups of either migrating early farmers or farmers and indigenous hunter-gatherers collided violently around 5300 BCE. This clash apparently resulted in a massacre of the Els Trocs farmers. The overkill reaction was possibly triggered by xenophobia or massive disputes over resources or privileges. In the present, violence and xenophobia are controlled and sanctioned through social codes of conduct and institutions. So that, rather than representing an insurmountable evolutionary inheritance, violence and ethnic nepotism can be overcome and a sustainable future achieved through mutual respect, tolerance and openness to multi-ethnic societies.

The maternal genetic make-up of the Iberian Peninsula between the Neolithic and the Early Bronze Age.

Agriculture first reached the Iberian Peninsula around 5700 BCE. However, little is known about the genetic structure and changes of prehistoric populations in different geographic areas of Iberia. In our study, we focus on the maternal genetic makeup of the Neolithic (~ 5500-3000 BCE), Chalcolithic (~ 3000-2200 BCE) and Early Bronze Age (~ 2200-1500 BCE). We report ancient mitochondrial DNA results of 213 individuals (151 HVS-I sequences) from the northeast, central, southeast and southwest regions and thus on the largest archaeogenetic dataset from the Peninsula to date. Similar to other parts of Europe, we observe a discontinuity between hunter-gatherers and the first farmers of the Neolithic. During the subsequent periods, we detect regional continuity of Early Neolithic lineages across Iberia, however the genetic contribution of hunter-gatherers is generally higher than in other parts of Europe and varies regionally. In contrast to ancient DNA findings from Central Europe, we do not observe a major turnover in the mtDNA record of the Iberian Late Chalcolithic and Early Bronze Age, suggesting that the population history of the Iberian Peninsula is distinct in character.

Neanderthal behaviour, diet, and disease inferred from ancient DNA in dental calculus.

Recent genomic data have revealed multiple interactions between Neanderthals and modern humans, but there is currently little genetic evidence regarding Neanderthal behaviour, diet, or disease. Here we describe the shotgun-sequencing of ancient DNA from five specimens of Neanderthal calcified dental plaque (calculus) and the characterization of regional differences in Neanderthal ecology. At Spy cave, Belgium, Neanderthal diet was heavily meat based and included woolly rhinoceros and wild sheep (mouflon), characteristic of a steppe environment. In contrast, no meat was detected in the diet of Neanderthals from El Sidrón cave, Spain, and dietary components of mushrooms, pine nuts, and moss reflected forest gathering. Differences in diet were also linked to an overall shift in the oral bacterial community (microbiota) and suggested that meat consumption contributed to substantial variation within Neanderthal microbiota. Evidence for self-medication was detected in an El Sidrón Neanderthal with a dental abscess and a chronic gastrointestinal pathogen (Enterocytozoon bieneusi). Metagenomic data from this individual also contained a nearly complete genome of the archaeal commensal Methanobrevibacter oralis (10.2× depth of coverage)-the oldest draft microbial genome generated to date, at around 48,000 years old. DNA preserved within dental calculus represents a notable source of information about the behaviour and health of ancient hominin specimens, as well as a unique system that is useful for the study of long-term microbial evolution.

A Community in Life and Death: The Late Neolithic Megalithic Tomb at Alto de Reinoso (Burgos, Spain).

The analysis of the human remains from the megalithic tomb at Alto de Reinoso represents the widest integrative study of a Neolithic collective burial in Spain. Combining archaeology, osteology, molecular genetics and stable isotope analysis (87Sr/86Sr, δ15N, δ13C) it provides a wealth of information on the minimum number of individuals, age, sex, body height, pathologies, mitochondrial DNA profiles, kinship relations, mobility, and diet. The grave was in use for approximately one hundred years around 3700 cal BC, thus dating from the Late Neolithic of the Iberian chronology. At the bottom of the collective tomb, six complete and six partial skeletons lay in anatomically correct positions. Above them, further bodies represented a subsequent and different use of the tomb, with almost all of the skeletons exhibiting signs of manipulation such as missing skeletal parts, especially skulls. The megalithic monument comprised at least 47 individuals, including males, females, and subadults, although children aged 0-6 years were underrepresented. The skeletal remains exhibited a moderate number of pathologies, such as degenerative joint diseases, healed fractures, cranial trauma, and a low intensity of caries. The mitochondrial DNA profiles revealed a pattern pointing to a closely related local community with matrilineal kinship patterns. In some cases adjacent individuals in the bottom layer showed familial relationships. According to their strontium isotope ratios, only a few individuals were likely to have spent their early childhood in a different geological environment, whilst the majority of individuals grew up locally. Carbon and nitrogen isotope analysis, which was undertaken to reconstruct the dietary habits, indicated that this was a homogeneous group with egalitarian access to food. Cereals and small ruminants were the principal sources of nutrition. These data fit in well with a lifestyle typical of sedentary farming populations in the Spanish Meseta during this period of the Neolithic.

Tracing patterns of activity in the human skeleton: an overview of methods, problems, and limits of interpretation.

Studies of patterns of activity in human skeletal remains have grown in number over the last few years. Different methods have been used to reconstruct activity patterns in past populations. In this review of the available literature the common themes of these studies have been isolated in order to show that many studies do not truly conform to the standards of the field. Inadequate sample size, too far-reaching conclusions and neglect of other possible explanations are among the problems easily recognised in the literature. Many assumptions are lacking a sound experimental basis, and it becomes increasingly evident that there are many more problems and limits of interpretations than have been usually acknowledged in the recent past. It also appears that many results, which have been interpreted in terms of sexual division of labour may, in fact, be expressions of the intrinsic sexual dimorphism of Homo sapiens and not culture- or population-specific peculiarities. Acknowledging the results of many studies from the field of sports medicine it appears doubtful that adult patterns of activity can truly be isolated from those which stem from the formative years of the human skeleton during the subadult growth period. A more cautious approach to the interpretation of data and a return to more basic research are needed to adequately address all the possibly confounding issues when trying to reconstruct patterns of activity from archaeological skeletal remains.