A critical test of twelve methods for estimating age using radiographic staging of developing teeth on a sample of 6- to 15-year-old children from Mérida, Yucatán (México).

Cross-population applicability of osteological and dental methods is a known issue in forensic anthropology, but very little is known about whether differences between populations are due to ancestry, environment effects, or even the statistical approach utilized for developing the methods. This study wishes to add to the discussion of population-specificity of dental age estimation methods and examine the impact of their statistical basis on their accuracy and precision. These parameters were estimated by testing 12 different dental age estimation techniques on a sample of 182 panoramic radiographs of children between the ages of 6 and 15 years (110 girls and 72 boys) from the city of Mérida in Yucatán, México. None of the 12 methods selected is based on Mexican samples. Dental maturation was scored following and methods tested employed two dental scoring schemes: Moorrees, Fanning, and Hunt's (MFH) 13-/14-stage system and Demirjian's 8-stage system. Results show that methods derived from more geographically specific groups do not fare better or worse than methods developed on more diverse and inclusive international samples, even if no methods specific to Mexicans were tested. While some of the methods performed very well, and they were not based on a Mexican sample, this suggests that population-specific dental age estimation methods may be relatively unimportant or that population differences in dental maturation are very small. Other issues seemed to have a greater impact on accuracy and precision, such as age dependency, inclusion of the third molar in age assessments, age truncation and age heaping in reference samples, the dental scoring scheme used, and how predicted age is calculated mathematically. As such, findings in this study suggest that validation tests of age estimation methods may not be a useful or reliable means to assess population differences and that these differences need to be more systematically assessed if an argument is to be made for the increased accuracy and precision of population-specific methods. The statistical basis of dental prediction methods seems to have a more significant role in their accuracy and precision outside of their reference sample.

Zebrafish embryo extracts enhance 5-FU anti-cancer effects upon breast cancer cells.

OBJECTIVE: The inhibition of the metastatic capability of cancer cells is a pivotal aim of current anticancer strategies. We investigated herein the anti-migrating and anti-invasive properties of Zebrafish embryo extracts (SL) - an integrative formula comprising morphogenetic factors extracted from zebrafish embryos - alone or in association with 5-Fluoro-Uracil (5-FU), when added to metastatic breast cancer cells (MDA-MB-231) and in normal epithelial breast cells (MCF10A) committed toward an inflammatory phenotype upon TGF-ß1 stimulation. MATERIALS AND METHODS: Invasiveness, migrating capability, cytoskeleton architecture and related molecular factors involved in the epithelial-mesenchymal transition were studied after treatment with 5-FU, with and without SL. RESULTS: Remarkably, in both circumstances, embryo extracts amplify the migratory inhibition triggered by the anticancer drug 5-Fu. The fact that such an effect is noticed in normal as well as in cancerous cells suggests that the critical target of embryo extracts is specifically represented by the migrating/invasive phenotype. However, while 5-FU was unable in antagonizing the invasiveness of cancerous cells, the association with SL can significantly impair the invasive capability of tumor cells. These findings are noticeably associated with the reversion of the EMT phenotype in SL-treated cells, as documented by the contemporary downregulation of TCTP and some EMT-related molecular effectors, like α-SMA and Vimentin. CONCLUSIONS: Embryo fish extracts significantly counteract the migrating and invasive phenotype of cancerous and inflammatory breast cells treated with the chemotherapeutic drug 5-FU. The availability of a compound able to amplify 5-Fu activity while significantly hampering the invasive phenotype of breast cancer should provide invaluable benefits, namely if we consider that this compound is substantially deprived of side-effects.

Pulp pathosis associated with ancient Maya dental inlays.

OBJECTIVE: The ancient Maya used to practice dental inlays as part of the cultural traditions. Most of those inlays remain in place after more than one thousand years. The purpose of this paper is to investigate the incidence of pulp pathosis associated with ancient Maya dental inlays to assess the impact that such common practice had on the population's oral health. DESIGN: We scored 193 anterior inlaid teeth from 107 pre-Hispanic Maya dentitions studied at three archaeological storage facilities (Universidad Autonoma de Yucatan, Harvard University, Atlas of Guatemala Project). Two hundred eleven untreated frontal teeth of pre-Hispanic Mayan collections were used as controls. We performed macroscopic, radiographic and microscopic analyses to assess the frequency of caries, pulp calcifications, internal root resorption (IRR), and periapical lesions (PALs). RESULTS: In the inlaid teeth, the frequencies of pulp calcifications, IRR, caries and PALs were 59.8%, 2.2%, 18.5% and 19.2%, respectively. Compared with untreated teeth, inlaid specimens exhibited greater susceptibility to caries, pulp calcifications, IRR and PALs than untreated teeth (pulp calcifications: 44.5%, IRR: 0%, caries: 1.4%, and PAL: 1.9%). Age-at-death did not have any significant influence on susceptibility to pulp calcifications, IRR, caries or PALs. CONCLUSIONS: We noted relatively low pulp irritation and a low frequency of carious infections, IRR and PALs in Mayan inlaid teeth. However, these levels exceeded the frequencies of untreated teeth from the same area and time period. We follow that the cements used by the pre-Hispanic Maya to fix the inlays into their sockets provided excellent sealing characteristics on average.

Natural products - alpha-lipoic acid and acetyl-L-carnitine - in the treatment of chemotherapy-induced peripheral neuropathy.

OBJECTIVE: Cancer patients frequently experience Chemotherapy-Induced Peripheral Neuropathy (CIPN), as a typical side effect related to time of administration and dose of anticancer agents. Yet, CIPN pathophysiology is poorly understood, and there is a lack of well-tolerated pharmacological remedies helpful to prevent or treat it. Therefore, new safe and effective compounds are highly warranted, namely if based on an adequate understanding of the pathogenic mechanisms. MATERIAL AND METHODS: Herein we reviewed and discussed scientific data related to the beneficial role of some non-conventional treatments able to counteract CIPN, focusing our attention on alpha-lipoic acid (ALA) and L-acetyl-carnitine (LAC), two natural products that have been demonstrated to be promising preventive drugs. RESULTS: Although a growing body of in vitro and in vivo studies support ALA as a molecule able to counteract CIPN symptoms, mostly due to its antioxidant and anti-inflammatory properties, only two randomized clinical trials evaluated ALA usefulness in preventing chemotherapy-related neuropathy. Unfortunately, these studies were inconclusive and clinical outcomes showed to be highly dependent on the route of administration (oral versus or intravenous injection). LAC has demonstrated beneficial effects on both in vitro and in animal studies. Yet, some controversies aroused from randomized clinical trials. Indeed, while CIPN-patients treated with Taxane showed no benefit from LAC treatment, CIPN-patients treated with platinum compounds exhibit significant improvement of CIPN-related symptoms. Therefore, LAC treatment should be used, and thoroughly investigated only in patients treated with chemotherapy protocols Taxanes-free. CONCLUSIONS: Mechanisms of toxicity triggered by each single drug need to be deeply explored to better identify effective compounds to prevent or treat them. Moreover, additional experiments are mandatory to establish effective doses and length of treatment for each clinical situation in order to perform large and long-term randomized studies.

Inositol hexaphosphate (InsP6) as an effective topical treatment for patients receiving adjuvant chemotherapy after breast surgery.

OBJECTIVE: Oral treatment with inositol hexaphosphate (InsP6) has shown to be efficient in decreasing adverse effects in patients with breast cancer under chemotherapy. This study was aimed at evaluating and comparing the efficacy of topical InsP6 in improving quality of life in women treated with anticancer drugs. PATIENTS AND METHODS: The study was a double-blind, randomized controlled trial (RCT) with allocation concealment of 20 patients in two groups, one (experimental) applied 4% topical formulation of InsP6 once a day, whereas the second one (control) a gel containing hyaluronic acid. InsP6 therapy started 6 weeks after lumpectomy. Blood tests were monitored in both groups and quality of life was assessed using standardized QLQ-C30 and QLQ-BR23. RESULTS: Patients who applied InsP6 on the breast significantly improved their quality of life and functional status reducing side effects compared to control group; moreover, after treatment, a significant difference between the two groups was observed in the white blood cells and platelets count values. CONCLUSIONS: Topical InsP6 treatment has demonstrated to be effective and safe in preventing and/or mitigating chemotherapy-induced side effects as well as the preserving quality of life in women with ductal breast cancer.

A randomized trial of Boswellia in association with betaine and myo-inositol in the management of breast fibroadenomas.

OBJECTIVE: Breast fibroadenoma is a common finding in young women and actually accounts for the majority of benign breast lumps. Fibroadenoma does not require any treatment unless clinical symptoms (mostly mastalgia) or histological markers of cancer risk (atypia) impose specific medical or surgical intervention. In symptomatic fibroadenoma, anti-estrogenic treatments provided evidence of success. Yet, these therapies are often associated with relevant side effects that lead to drug treatment discontinuation. Additionally, in such cases, relapse is a frequent issue. Therefore, an optimal strategy is still warranted. Boswellia, betaine and myo-inositol have already been proved to modulate different pathways - inflammatory, metabolic, oxidative and endocrine processes - in a wide array of human tissues. Based on that background, we hypothesized that these substances can effectively synergize in inducing the regression of fibroadenoma. PATIENTS AND METHODS: We included 64 patients ≤ 30 years of age with fibroadenoma. The patients were randomized into two groups. The experimental group was treated with an association of Boswellia, betaine, myo-inositol, B-group vitamins and N-acetylcysteine for 6 months; otherwise, the placebo group was treated only with B-group vitamins and N-acetylcysteine. Patients were monitored at the enrollment and the end of the study for evaluating the clinical response. RESULTS: A significant clinical improvement was observed in the experimental arm. Fibroadenoma median volume reduction averaged 17.86% in the experimental group and 5.96% in the placebo group. Moreover, 14 out of 36 (38.88%) patients showed a reduction of fibroadenoma volume compared to 5/28 (17.85%) observed in the placebo group (p = 0.005). CONCLUSIONS: A supplementation with Boswellia, betaine and myo-inositol reduces fibroadenoma dimension in young women. No relevant side effects have been recorded.

Intra-population dental morphological variability among the Prehispanic Maya.

The present paper proposes a new approach to the estimation of intra-site variability of dental morphological traits when they are dichotomized into presence vs absence. It rests on the assumption that (1) higher intra-site variability is the expression of intense population dynamics and gene flow; and (2) maximum variability is reached when each trait is expressed in the population with a frequency of 50%. The approach simulates the calculation of frequency of heterozygotes in Mendelian traits (2xiyi), where xi and yi are the frequency of presence and absence of the trait. For every population, the final value corresponds to the average of (2xiyi) calculated from all the scored traits. Two separate analyses were performed using 50 and 40 traits recorded in 11 Prehispanic Maya skeletal collections from the Yucatán Peninsula. Resulting average values were related to the sites' positions within the region's social, political and economic sphere of influence. Dental collections that were obtained from important city centers or by grouping many sites from a single region present the highest values of internal variability, followed by sites known to have played an important role in trade activities or in other socio-political contexts. At the other end, dental collections that represent smaller communities or more isolated, kin-related groups are set at the lower ranks of internal variability. One-way ANOVA tests for both 50 and 40 variables show that sample means present significant differences between the extreme ends of the ranked set of samples.

An association of boswellia, betaine and myo-inositol (Eumastós) in the treatment of mammographic breast density: a randomized, double-blind study.

OBJECTIVE: Mammographic breast density is a recognized risk factor for breast cancer. The causes that lead to the proliferation of the glandular breast tissue and, therefore, to an increase of breast density are still unclear. However, a treatment strategy to reduce the mammary density may bring about very relevant clinical outcomes in breast cancer prevention. Myo-inositol is a six-fold alcohol of cyclohexane, has already been proved to modulate different pathways: inflammatory, metabolic, oxidative and endocrine processes, in a wide array of human diseases, including cancer and the genesis of mammary gland and breast diseases, like fibrosis, as well as metabolic and endocrine cues. Similarly, boswellic acid and betaine (three-methyl glycine) both inhibit inflammation and exert protective effects on breast physiology. Based on this scientific background, we hypothesized that a combination including, boswellic acid, betaine and myo-inositol would be able to reduce breast density working on different pathways. PATIENTS AND METHODS: In this study, seventy-six premenopausal women were randomly assigned to the placebo and the experimental drug arms (Eumastós) for six months. RESULTS: After 6 months of treatment, statistically significant difference between the two groups was recorded on the breast density reduction (60% vs. 9%), using mammographic as well as ultrasound examination. CONCLUSIONS: Preliminary data collected here with support the starting assumptions, that the association comprising boswellic acid, betaine and myo-inositol significantly reduces mammary density, providing the first evidence for a new and safe approach for the management of mammographic density treatment.

The C-shaped canal molar: an Endodontic-Archaeological study of the relationships between Mayan pre-Hispanic and contemporary population of Yucatán.

AIM: To assess the prevalence of C-shaped canal systems in mandibular second molars, in samples of modern and pre-Hispanic Mayan individuals in Yucatán, Mexico, and to analyse the trait through time and attempt to find new evidence of ethnical bonds between populations. METHODOLOGY: Three hundred and forty-one randomly selected patients were treated in the Endodontic Clinic at the Dental school of the Universidad Autónoma de Yucatán, and 48 mandibular second molars from pre-Hispanic Mayan collections were macroscopically and radiographically inspected. Statistical analysis was performed with a Fisher's exact test to compare the prevalence of C-shaped canal systems in modern and archaeological samples. RESULTS: In the clinical observation, 118 of 341 (35%) patients treated endodontically had C-shaped mandibular second molars. In the radiographical evaluation, 17 of 48 (35%) archaeological molars had fused roots and pulp chamber morphology categorized as C-shaped. There were no significant differences between the frequencies in both samples. CONCLUSION: This study highlighted that a one-rooted mandibular molar was likely to have a C-shaped canal. The similarity between ancient and modern samples indicates that the genetic make-up since the European conquest has not affected the expression of this trait. This study supports the theory that the Mayan population has a relationship with the Northeast Asian population.

Physical forces and non linear dynamics mould fractal cell shape: quantitative morphological parameters and cell phenotype.

Cell shape is mainly determined by biophysical constraints, interacting according to non-linear dynamics upon the basic units provided by the genome. In turn, the specific configuration a cell acquires plays a fundamental, permissive role in modulating gene expression and many other complex biological functions. Cell shape is tightly connected to cell activity and can be considered the most critical determinant of cell function. As a consequence, measurable parameters describing shape could be considered as 'omics' descriptors of the specific level of observation represented by the cell-stroma system. Such an approach promises to formalize some of the underlying basic mechanisms and, ultimately, provide a holistic understanding of the biological processes.

Quantitative shape analysis of chemoresistant colon cancer cells: correlation between morphotype and phenotype.

Morphological, qualitative observations allow pathologists to correlate the shape the cells acquire with the progressive, underlying neoplastic transformation they are experienced. Cell morphology, indeed, roughly scales with malignancy. A quantitative parameter for characterizing complex irregular structures is the Normalized Bending Energy (NBE). NBE provides a global feature for shape characterization correspondent to the amount of energy needed to transform the specific shape under analysis into its lowest energy state. We hypothesized that a chemotherapy resistant cancer cell line would experience a significant change in its shape, and that such a modification might be quantified by means of NBE parameterization. We checked out the usefulness of a mathematical algorithm to distinguish wild and 5-fluorouracil (5-FU)-resistant colon cancer HCT-8 cells (HCT-8FUres). NBE values, as well as cellular and molecular parameters, were recorded in both cell populations. Results demonstrated that acquisition of drug resistance is accompanied by statistically significant morphological changes in cell membrane, as well as in biological parameters. Namely, NBE increased progressively meanwhile cells become more resistant to increasing 5-FU concentrations. These data indicate how tight the relationships between morphology and phenotype is, and they support the idea to follow a cell transition toward a drug-resistant phenotype by means of morphological monitoring.

Fractal analysis in a systems biology approach to cancer.

Cancer is a highly complex disease due to the disruption of tissue architecture. Thus, tissues, and not individual cells, are the proper level of observation for the study of carcinogenesis. This paradigm shift from a reductionist approach to a systems biology approach is long overdue. Indeed, cell phenotypes are emergent modes arising through collective non-linear interactions among different cellular and microenvironmental components, generally described by "phase space diagrams", where stable states (attractors) are embedded into a landscape model. Within this framework, cell states and cell transitions are generally conceived as mainly specified by gene-regulatory networks. However, the system's dynamics is not reducible to the integrated functioning of the genome-proteome network alone; the epithelia-stroma interacting system must be taken into consideration in order to give a more comprehensive picture. Given that cell shape represents the spatial geometric configuration acquired as a result of the integrated set of cellular and environmental cues, we posit that fractal-shape parameters represent "omics" descriptors of the epithelium-stroma system. Within this framework, function appears to follow form, and not the other way around.

Zebrafish stem cell differentiation stage factors suppress Bcl-xL release and enhance 5-Fu-mediated apoptosis in colon cancer cells.

Stem cell differentiation stage factors (SCDSF), taken from Zebrafish embryos during the stage in which totipotent stem cells are differentiating into pluripotent stem cells, have been shown to inhibit proliferation and induce apoptosis in colon tumors. In order to ascertain if these embryonic factors could synergistically/additively interact with 5-Fluorouracil (5-Fu), whole cell-count, flow-cytometry analysis and apoptotic parameters were recorded in human colon cancer cells (Caco2) treated with Zebrafish stem cell differentiation stage factors (SCDSF 3 µg/ml) in association or not with 5-Fu in the sub-pharmacological therapeutic range (0.01 mg/ml). Cell proliferation was significantly reduced by SCDSF, meanwhile SCDSF+5-Fu leads to an almost complete growth-inhibition. SCDSF produces a significant apoptotic effect, meanwhile the association with 5-FU leads to an enhanced additive apoptotic rate at both 24 and 72 hrs. SCDSF alone and in association with 5-Fu trigger both the extrinsic and the intrinsic apoptotic pathways, activating caspase-8, -3 and -7. SCDSF and 5-Fu alone exerted opposite effects on Bax and Bcl-xL proteins, meanwhile SCDSF+5-Fu induced an almost complete suppression of Bcl-xL release and a dramatic increase in the Bax/Bcl-xL ratio. These data suggest that zebrafish embryo factors could improve chemotherapy efficacy by reducing anti-apoptotic proteins involved in drug-resistance processes.

Embryonic morphogenetic field induces phenotypic reversion in cancer cells. Review article.

Cancer cells introduced into developing embryos can be committed to a complete reversion of their malignant phenotype. It is unlikely that such effects could be ascribed to only few molecular components interacting according to a simple linear-dynamics model, and they claim against the somatic mutation theory of cancer. Some 50 years ago, Needham and Waddington speculated that cancer represents an escape from morphogenetic field like those which guide embryonic development. Indeed, disruption of the morphogenetic field of a tissue can promote the onset as well as the progression of cancer. On the other hand, placing tumor cells into a "normal" morphogenetic field - like that of an embryonic tissue - one can reverse malignant phenotype, "reprogramming" tumor into normal cells. According to the theoretical framework provided by the thermodynamics of dissipative systems, morphogenetic fields could be considered as distinct attractors, to which cell behaviors are converging. Cancer-attractors are likely positioned somewhat close to embryonic-attractors. Indeed, tumors share several morphological and ultra-structural features with embryonic cells. The recovering of an "embryonic-like" cell shape might enable the gene regulatory network to reactivate embryonic programs, and consequently to express antigenic and biochemical embryonic characters. This condition confers to cancer an unusual sensitivity to embryonic regulatory cues. Thus, it is not surprising that cancer cells exposed to specific embryonic morphogenetic fields undergoes significant modifications, eventually leading to a complete phenotypic reversion.

Multiwalled carbon nanotube buckypaper: toxicology and biological effects in vitro and in vivo.

AIM: We evaluated the effect of buckypaper (BP) on cancer and primary cell lines in vitro and in vivo in laboratory rats. BP is an innovative material with interesting physical/chemical properties that has possible pharmacological and prosthetic employment. Given that precautions need to be taken where carbon nanotubes are injected into human body for drug delivery, as contrast agent-carrying entities for MRI or as the material of a new prosthesis generation, we assessed the toxicity of BP carbon nanotubes. BP has structural resemblance to asbestos, whose toxicity has been linked to cancer. RESULTS: BP decreased proliferation of human colorectal, breast and leukemic cancer cell lines in vitro. However, BP had no effect on the proliferation and viability of normal human arterial smooth muscle cells and human dermal fibroblasts in vitro. in vivo, BP induced a moderate inflammatory reaction but had no mutagenic effects. After BP implantation the animals showed an inflammatory reaction followed 2 weeks later by a cicatrization reaction with the organization and fibrosis of the scar. CONCLUSION: These results show a low toxicity of BP both in vitro and in vivo.

Linear enamel hypoplasia at Xcambó, Yucatán, during the Maya Classic period: An evaluation of coastal marshland impact on ancient human populations.

Non-specific stress markers such as linear enamel hypoplasia (LEH) have been associated in the literature with a large number of possible conditions disrupting the individual's homeostasis, though metabolic strain originating synergistically by disease and malnutrition has been held to be the main cause behind enamel disruption. The analysis of LEH in the Maya Classic period site of Xcambó, located along the northern coast of the Yucatán peninsula, reveals high exposure to stressful conditions during infancy regardless of age and sex. Yet, the inhabitants of the site were of a medium to high social and economic status, with access to balanced and protein-rich nutritional resources, which should have functioned as a cultural buffer to the impact of stress. In the light of this apparent contradiction, this paper discusses the impact of environmental conditions on the record of metabolic stress. Our conclusions pose a cautionary caveat for inferring nutrition and status in ancient pre-antibiotic populations solely from the occurrence of linear enamel hypoplasia.

Beyond the oncogene paradigm: understanding complexity in cancerogenesis.

In the past decades, an enormous amount of precious information has been collected about molecular and genetic characteristics of cancer. This knowledge is mainly based on a reductionistic approach, meanwhile cancer is widely recognized to be a 'system biology disease'. The behavior of complex physiological processes cannot be understood simply by knowing how the parts work in isolation. There is not solely a matter how to integrate all available knowledge in such a way that we can still deal with complexity, but we must be aware that a deeply transformation of the currently accepted oncologic paradigm is urgently needed. We have to think in terms of biological networks: understanding of complex functions may in fact be impossible without taking into consideration influences (rules and constraints) outside of the genome. Systems Biology involves connecting experimental unsupervised multivariate data to mathematical and computational approach than can simulate biologic systems for hypothesis testing or that can account for what it is not known from high-throughput data sets. Metabolomics could establish the requested link between genotype and phenotype, providing informations that ensure an integrated understanding of pathogenic mechanisms and metabolic phenotypes and provide a screening tool for new targeted drug.

Locoregional IL-2 therapy in the treatment of colon cancer. Cell-induced lesions of a murine model.

BACKGROUND: Local therapy with IL-2 may be very effective in the treatment of different forms of cancer. The aim of this study was to determine the effectiveness of IL-2 locoregional application in the treatment of colon cancer. MATERIALS AND METHODS: Twenty eight syngenic BDIX rats were utilized in this study. The rats were divided into two groups of fourteen animals: group T (treatment) and group C (control). All rats of both groups were injected, under the splenic capsule, with T 10(7) DHD/K2/ TRb neoplastic cells. Then, within and around the site of the previous inoculation, the T group was injected with 1 ml of glucosate solutions + 0.1% albumin (BSA) containing 2.5 x 10(6) IU of IL-2 ( Proleukin-Chiron), whereas the C group was injected with 1 ml of BSA alone. After three weeks, rats were sacrificed and the liver and spleen were removed. The following parameters were considered: volume and weight, neoplastic-non neoplastic tissue index of the spleen, mitotic index and vascular density of splenic and hepatic lesions. RESULTS: All the studied parameters showed statistically significant differences in treated and untreated animals. CONCLUSION: This study of a murine model demonstrated that IL-2 locoregional therapy may be effective in the treatment of colon cancer.

Origins and spread of agriculture in Italy: a nonmetric dental analysis.

Dental morphological traits were employed in this study as direct indicators of biological affinities among the populations that inhabited the Italian peninsula from the Upper Paleolithic-Mesolithic to Medieval times. Our analysis aims at contributing to the ongoing debate regarding the origin and spread of agriculture in the peninsula by contrasting the dental evidence of archaeological and modern molecular samples. It is not possible to generalize given the complex and dynamic nature of these populations. However, the results from the principal component analysis, maximum likelihood, mean measure of divergence, and multidimensional scaling do indicate a net separation of the Paleo-Mesolithic sample from the other groups that is not related to dental reduction. This suggests that the shift in dental morphology was the product of Neolithic populations migrating into the peninsula from other areas. Nonetheless, the Paleo-Mesolithic populations share several discriminative traits with the Neolithic group. The biological relevance of such evidence suggests that, to some minor extent, the spread of agriculture did not occur by total population replacement. Because of regional small sample sizes, this hypothesis cannot be tested on a micro-regional scale. It is, however, feasible to depict a scenario where processes of genetic mixture or replacement probably took place at different rates on a macro-regional level.

Palaeontology: early Neolithic tradition of dentistry.

Prehistoric evidence for the drilling of human teeth in vivo has so far been limited to isolated cases from less than six millennia ago. Here we describe eleven drilled molar crowns from nine adults discovered in a Neolithic graveyard in Pakistan that dates from 7,500-9,000 years ago. These findings provide evidence for a long tradition of a type of proto-dentistry in an early farming culture.