A comparison of proteomic, genomic, and osteological methods of archaeological sex estimation

Sex estimation in a Chilean population by mandibular analysis in cone beam computed tomography images

BACKGROUND

Sex estimation is the first stage in the identification of an individual in the forensic context, and can be carried out from bone structures like the mandible. The aim of this study was to estimate sex from metric analysis of the mandible in cone beam computed tomography images (CBCT) of adult Chilean individuals.

METHODS

Six mandibular measurements were analysed, five linear and one angular, in CBCT of adult Chilean individuals of both sexes. ROC Curve analysis was performed, with cut-off points, and of the overall model quality. Univariate discriminant function analysis was used to determine the accuracy of each measurement for sex estimation. Multivariate discriminant function analysis, both directly and by steps, was used to obtain the predictive value of the mandible including all the measurements.

RESULTS

The data included were 155 CBCT, 105 of females and 50 of males. The mandible presented great sexual dimorphism, with the mandibular ramus presenting greater predictive power than the mandibular body. When each mandibular measurement was analysed separately, the maximum height of the mandibular ramus presented the greatest predictive power (76.5%), while the mandibular angle was the least accurate parameter for sex estimation (58.1%). Direct method analysis presented 87.1% accuracy for sex identification of adult Chilean individuals, and joint analysis of maximum mandibular ramus height (MRH), corono-condylar distance and bigonial breadth presented 86.5% accuracy. In ROC Curve analysis the MRH was the variable with the greatest discriminating capacity (AUC = 0.833), MA was the only variable which presented no discriminating capacity (AUC = 0.386) and also presented low quality in model quality analysis.

CONCLUSION

Metric analysis of the mandible in CBCT images presents an acceptable accuracy for sex estimation in Chilean individuals, and its use for that purpose in forensic practice is recommended.

Simulating the effects of kinship and postmarital residence patterns on mitochondrial DNA diversity in mortuary contexts

OBJECTIVES

We explore the observable outcome in mtDNA diversity of different kinship systems and associated postmarital residence patterns in the archeological record, using simulations at the intrapopulation level.

MATERIALS AND METHODS

Four kinship systems were simulated from a set of variable fertility and mortality scenarios. Initial conditions consisted of six clusters of variable size and a random number of assigned haplotypes, with individuals migrating between groups and reproducing for 15 generations. Each 15-generation span was simulated 500 times to obtain representative intrasite mtDNA diversity distributions for each kinship system. Additional simulations were devised to consider the effect of migration and different rates of adherence to kinship norms.

RESULTS

Matrilineal kinship generates low male and female haplotype diversities that are statistically indistinguishable from each other, while female diversity in bilateral kinship with matrilocality is significantly lower than that observed in male diversity. Furthermore, mtDNA diversity generated by patrilineal kinship is very high. The effect of noncompliance with kinship rules is low; migration has a considerable impact on diversity, eventually obscuring the effect of kinship practices.

DISCUSSION

The results of the simulations can be applied to ancient mtDNA data from archeological contexts, as exemplified with data from two studies. On a broader scale, the kinship system followed by the sampled population, can lead to either over- or underestimation of mtDNA population diversity. The results of the simulations can be used in the design of inferential frameworks to discern kinship scenarios in the archeological record, based on mtDNA and other types of evidence.

Female sex bias in Iberian megalithic societies through bioarchaeology, aDNA and proteomics

Uncertainties regarding traditional osteological methods in biological sex estimation can often be overcome with genomic and proteomic analyses. The combination of the three methodologies has been used for a better understanding of the gender-related funerary rituals at the Iberian megalithic cemetery of Panoría. As a result, 44 individuals have been sexed including, for the first time, non-adults. Contrary to the male bias found in many Iberian and European megalithic monuments, the Panoría population shows a clear sex ratio imbalance in favour of females, with twice as many females as males. Furthermore, this imbalance is found regardless of the criterion considered: sex ratio by tomb, chronological period, method of sex estimation, or age group. Biological relatedness was considered as possible sociocultural explanations for this female-related bias. However, the current results obtained for Panoría are indicative of a female-centred social structure potentially influencing rites and cultural traditions.

No Bones About It: Sex Is Binary

Anthropologists have led the way in formulating techniques that reveal skeletal differences between males and females. Understanding of physical differences in the pelvis related to childbirth, hormonal impacts on bones, and extensive comparative studies have provided anthropologists with an array of traits and measurements that help them estimate sex using just bones. Forensic anthropologists and bioarcheologists are improving their ability to differentiate males and females by increasing research on a variety of postcranial bones and through the use of molecular data, especially new methods called proteomics, to identify sex in prepubescent juveniles. As remains from more cultures and time periods are studied, sex identification will continue to improve, because skeletal sex differences are in large part biologically determined. Yet, anthropologists have also been at the forefront of arguing that sex lies on a spectrum. Anthropologists who view sex as on a spectrum may deter sex identification progress; from their perspective, an individual of an undetermined sex may just be a nonbinary individual. Anthropologists who consider sex is on a spectrum are coming to this conclusion in part because they are looking for anatomical ideals, mistaking pathology for variation, and confusing independent variables with dependent variables. Nonetheless, anthropologists need to continue to improve sex identification techniques to reconstruct the past accurately, which may reveal less strict sex roles than previously presumed and help with the identification of crime victims. Forensic anthropologists should also increase their efforts to identify whether individuals have undergone medical procedures intended to change one's gender due to the current rise in transitioning individuals.

Accurate Bayesian inference of sex chromosome karyotypes and sex-linked scaffolds from low-depth sequencing data

The identification of sex-linked scaffolds and the genetic sex of individuals, i.e. their sex karyotype, is a fundamental step in population genomic studies. If sex-linked scaffolds are known, single individuals may be sexed based on read counts of next-generation sequencing data. If both sex-linked scaffolds as well as sex karyotypes are unknown, as is often the case for non-model organisms, they have to be jointly inferred. For both cases, current methods rely on arbitrary thresholds, which limits their power for low-depth data. In addition, most current methods are limited to euploid sex karyotypes (XX and XY). Here we develop BeXY, a fully Bayesian method to jointly infer the posterior probabilities for each scaffold to be autosomal, X- or Y-linked and for each individual to be any of the sex karyotypes XX, XY, X0, XXX, XXY, XYY and XXYY. If the sex-linked scaffolds are known, it also identifies autosomal trisomies and estimates the sex karyotype posterior probabilities for single individuals. As we show with downsampling experiments, BeXY has higher power than all existing methods. It accurately infers the sex karyotype of ancient human samples with as few as 20,000 reads and accurately infers sex-linked scaffolds from data sets of just a handful of samples or with highly imbalanced sex ratios, also in the case of low-quality reference assemblies. We illustrate the power of BeXY by applying it to both whole-genome shotgun and target enrichment sequencing data of ancient and modern humans, as well as several non-model organisms.

Sex estimation of the adult Neandertal Regourdou 1 (Montignac, France): Implications for sexing human fossil remains

Sex is a biological trait fundamental to the study of hominin fossils. Among the many questions that can be addressed are those related to taxonomy, biological variability, sexual dimorphism, paleoobstetrics, funerary selection, and paleodemography. While new methodologies such as paleogenomics or paleoproteomics can be used to determine sex, they have not been systematically applied to Pleistocene human remains due to their destructive nature. Therefore, we estimated sex from the coxal bone of the newly discovered pelvic remains of the Regourdou 1 Neandertal (Southwest France, MIS 5) based on morphological and metric data employing two methods that have been recently revised and shown to be reliable in multiple studies. Both methods calculate posterior probabilities of the estimate. The right coxal bone of Regourdou 1 was partially reconstructed providing additional traits for sex estimation. These methods were cross validated on 14 sufficiently preserved coxal bones of specimens from the Neandertal lineage. Our results show that the Regourdou 1 individual, whose postcranial skeleton is not robust, is a male, and that previous sex attributions of comparative Neandertal specimens are largely in agreement with those obtained here. Our results encourage additional morphological research of fossil hominins in order to develop a set of methods that are applicable, reliable, and reproducible.

Windows into the past: recent scientific techniques in dental analysis

Teeth are the hardest and most chemically stable tissues in the body, are well-preserved in archaeological remains and, being resistant to decomposition in the soil, survive long after their supporting structures have deteriorated. It has long been recognised that visual and radiographic examination of teeth can provide considerable information relating to the lifestyle of an individual. This paper examines the latest scientific approaches that have become available to investigate recent and ancient teeth. These techniques include DNA analysis, which can be used to determine the sex of an individual, indicate familial relationships, study population movements, provide phylogenetic information and identify the presence of disease pathogens. A stable isotopic approach can shed light on aspects of diet and mobility and even research climate change. Proteomic analysis of ancient dental calculus can reveal specific information about individual diets. Synchrotron microcomputed tomography is a non-invasive technique which can be used to visualise physiological impactful events, such as parturition, menopause and diseases in cementum microstructure - these being displayed as aberrant growth lines.

Comparing Walker's (2008) skull trait sex estimation standard to proteomic sex estimation for a group of South Asian individuals

This research assesses the potential for misidentification of sex in individuals of South Asian ancestry using the Walker (2008) morphological skull sex estimation standard [1]. Chromosomal sex was assessed using proteomic analysis targeting sex chromosome-specific amylogenic peptides. Results showed that the Walker method produced incorrect classification for 36.7 % of individuals. Overwhelmingly, those incorrectly assigned were chromosomally male. Misidentification was due to males within the group having lower trait scores (i.e., more gracile traits) than the standard would predict. There was also a high level of overlap in trait scores between male and females indicating reduced expression of sexual dimorphism. The use of established multivariate statistical techniques improved accuracy of sex estimation in some cases, but larger osteological data sets from South Asian individuals are required to develop population-specific standards. We suggest that peptide analysis may provide a useful tool for the forensic anthropologist when assessing sex in populations without population specific osteological standards.

Unbalanced sex-ratio in the Neolithic individuals from the Escoural Cave (Montemor-o-Novo, Portugal) revealed by peptide analysis

The sex profile estimation of pre-historic communities is often complicated by the commingled and scattered nature of skeletal assemblages. Demographic profiles are usually lacking and provide very truncated representations of these populations but proteomic analysis of sex-specific amelogenin peptides in tooth enamel brings new promise to these studies. The main objective was to obtain the sex profile of the human assemblage recovered from the Neolithic cave-necropolis of Escoural (Montemor-o-Novo, southern Portugal) through liquid chromatography-mass spectrometry. The secondary objective was to analyse sex-specific linear enamel hypoplasias (LEH), and to test the reliability of canine odontometric sex estimation. Sex estimation through peptide analysis was carried out in 36 left permanent canines which were macroscopically examined for the presence of LEH. The canine buccolingual diameter was used for odontometric sex estimation. The obtained sex ratio (0.5:1, M:F) is biased to female individuals, probably due to cultural factors since the natural sex ratio of the human population falls between 0.95:1 and 1.02:1 (M:F). A high frequency of LEH was observed, but with no significant sexual differences (p = 0.554). The mean LEH age of onset occurred at 3 years of age, with no significant differences between the sexes (p = 0.116), and was possibly related to the weaning process. Odontometric sex estimation revealed a correct classification of 80%, with a high number of males mistakenly attributed to females. This study is one of the largest samples subjected to peptide analysis, and thus demonstrates its usefulness on the research of commingled and scattered skeletal assemblages.

Isotopic and proteomic evidence for communal stability at Pre-Pottery Neolithic Jericho in the Southern Levant

As one of the key, long-term occupied sites in the Southern Levant, Jericho was one of the most important early Neolithic centres to witness social and economic changes associated with the domestication of plants and animals. This study applies strontium (87Sr/86Sr), oxygen (δ18O) and carbon (δ13C) isotope analyses to the enamel of 52 human teeth from Pre-Pottery Neolithic (PPN) layers of Jericho to directly study human diet and mobility and investigate the degree of consolidation and the flexibility of social organization of Jericho society in the PPN period. The results indicate only two non-local individuals out of the 44 sampled inhabitants identified by strontium isotope analysis and are consistent with the presence of a largely sedentary community at PPN Jericho with no evidence for large-scale migration. We also construct strontium spatial baselines (87Sr/86Sr map) with local 87Sr/86Sr signatures for the sites across the Southern Levant based on systematic compilation and analysis of available data. In addition, we apply proteomic analysis of sex-specific amelogenin peptides in tooth enamel for sex estimation of the sampled individuals (n = 44), the results of which showed a sex-biased ratio (more male than female detected in this sample pool) in Jericho society during the PPN period, which may be due to the limited sample size or selective ritual practices like particular burial zones used for specific groups. We also pretreated a batch of human bone samples recovered from PPNB Jericho for stable carbon and nitrogen isotope analyses for dietary investigations. However, the extracted collagen showed poor preservation and no valid δ13C or δ15N data were obtained.

Recognizability of Demographically Altered Computerized Facial Approximations in an Automated Facial Recognition Context for Potential Application in Unidentified Persons Data Repositories

This study examined the recognizability of demographically altered facial approximations for potential utility in unidentified persons tracking systems. Five computer-generated approximations were generated for each of 26 African male participants using the following demographic parameters: (i) African male (true demographics), (ii) African female, (iii) Caucasian male, (iv) Asian male, and (v) Hispanic male. Overall, 62% of the true demographic facial approximations for the 26 African male participants examined were matched to a corresponding life photo within the top 50 images of a candidate list generated from an automated blind search of an optimally standardized gallery of 6159 photographs. When the African male participants were processed as African females, the identification rate was 50%. In contrast, less congruent identification rates were observed when the African male participants were processed as Caucasian (42%), Asian (35%), and Hispanic (27%) males. The observed results suggest that approximations generated using the opposite sex may be operationally informative if sex is unknown. The performance of approximations generated using alternative ancestry assignments, however, was less congruent with the performance of the true demographic approximation (African male) and may not yield as operationally constructive data as sex-altered approximations.

Application of natural sciences methodology in archaeological study of Iron Age burials in Latvia: pilot study

Natural sciences provide several modern methodologies that could be successfully applied in archaeological studies. In this pilot study, archaeological human remains from two Iron Age cemeteries (7th-twelfth centuries AD), Lejasbitēni and Čunkāni-Dreņģeri, which are located in different regions of Latvia, were studied. We applied ancient DNA (aDNA) and tooth enamel peptide analysis to determine the biological sex of the individuals. In addition, aDNA analysis was used to perform mtDNA haplogroup analysis. In most cases, the results of aDNA analysis regarding the biological sex of individuals coincided with the gender assigned based on grave orientation and grave goods. The results of sex determination using peptide analysis in all four individuals for whom data were available matched the possible gender. Of the 17 samples that had sufficient DNA for sequencing, seven samples had enough reads to perform mtDNA haplogroup analysis. The H2a2a, I4a1, H2a2a1, and H16c mtDNA haplogroups were identified in the individuals from the Lejasbitēni cemetery, while the T2b and K1a + 150 mtDNA haplogroups were identified in the individuals from the Čunkāni-Dreņģeri cemetery. Overall, the obtained results demonstrated the feasibility of applying aDNA and tooth enamel peptide analysis for biological sex determination within archaeological studies. The availability of human aDNA data will be highly useful for investigating the demographic history and social structures in Iron Age Latvia.

Cranial and Odontological Methods for Sex Estimation-A Scoping Review

The estimation of sex from osteological and dental records has long been an interdisciplinary field of dentistry, forensic medicine and anthropology alike, as it concerns all the above mentioned specialties. The aim of this article is to review the current literature regarding methods used for sex estimation based on the skull and the teeth, covering articles published between January 2015 and July 2022. New methods and new approaches to old methods are constantly emerging in this field, therefore resulting in the need to summarize the large amount of data available. Morphometric, morphologic and biochemical analysis were reviewed in living populations, autopsy cases and archaeological records. The cranial and odontological sex estimation methods are highly population-specific and there is a great need for these methods to be applied to and verified on more populations. Except for DNA analysis, which has a prediction accuracy of 100%, there is no other single method that can achieve such accuracy in predicting sex from cranial or odontological records.

Paleoproteomics

Paleoproteomics, the study of ancient proteins, is a rapidly growing field at the intersection of molecular biology, paleontology, archaeology, paleoecology, and history. Paleoproteomics research leverages the longevity and diversity of proteins to explore fundamental questions about the past. While its origins predate the characterization of DNA, it was only with the advent of soft ionization mass spectrometry that the study of ancient proteins became truly feasible. Technological gains over the past 20 years have allowed increasing opportunities to better understand preservation, degradation, and recovery of the rich bioarchive of ancient proteins found in the archaeological and paleontological records. Growing from a handful of studies in the 1990s on individual highly abundant ancient proteins, paleoproteomics today is an expanding field with diverse applications ranging from the taxonomic identification of highly fragmented bones and shells and the phylogenetic resolution of extinct species to the exploration of past cuisines from dental calculus and pottery food crusts and the characterization of past diseases. More broadly, these studies have opened new doors in understanding past human-animal interactions, the reconstruction of past environments and environmental changes, the expansion of the hominin fossil record through large scale screening of nondiagnostic bone fragments, and the phylogenetic resolution of the vertebrate fossil record. Even with these advances, much of the ancient proteomic record still remains unexplored. Here we provide an overview of the history of the field, a summary of the major methods and applications currently in use, and a critical evaluation of current challenges. We conclude by looking to the future, for which innovative solutions and emerging technology will play an important role in enabling us to access the still unexplored "dark" proteome, allowing for a fuller understanding of the role ancient proteins can play in the interpretation of the past.

Twenty-first century bioarchaeology: Taking stock and moving forward

This article presents outcomes from a Workshop entitled "Bioarchaeology: Taking Stock and Moving Forward," which was held at Arizona State University (ASU) on March 6-8, 2020. Funded by the National Science Foundation (NSF), the School of Human Evolution and Social Change (ASU), and the Center for Bioarchaeological Research (CBR, ASU), the Workshop's overall goal was to explore reasons why research proposals submitted by bioarchaeologists, both graduate students and established scholars, fared disproportionately poorly within recent NSF Anthropology Program competitions and to offer advice for increasing success. Therefore, this Workshop comprised 43 international scholars and four advanced graduate students with a history of successful grant acquisition, primarily from the United States. Ultimately, we focused on two related aims: (1) best practices for improving research designs and training and (2) evaluating topics of contemporary significance that reverberate through history and beyond as promising trajectories for bioarchaeological research. Among the former were contextual grounding, research question/hypothesis generation, statistical procedures appropriate for small samples and mixed qualitative/quantitative data, the salience of Bayesian methods, and training program content. Topical foci included ethics, social inequality, identity (including intersectionality), climate change, migration, violence, epidemic disease, adaptability/plasticity, the osteological paradox, and the developmental origins of health and disease. Given the profound changes required globally to address decolonization in the 21st century, this concern also entered many formal and informal discussions.

How low can you go? Introducing SeXY: sex identification from low-quantity sequencing data despite lacking assembled sex chromosomes

Accurate sex identification is crucial for elucidating the biology of a species. In the absence of directly observable sexual characteristics, sex identification of wild fauna can be challenging, if not impossible. Molecular sexing offers a powerful alternative to morphological sexing approaches. Here, we present SeXY, a novel sex-identification pipeline, for very low-coverage shotgun sequencing data from a single individual. SeXY was designed to utilize low-effort screening data for sex identification and does not require a conspecific sex-chromosome assembly as reference. We assess the accuracy of our pipeline to data quantity by downsampling sequencing data from 100,000 to 1000 mapped reads and to reference genome selection by mapping to a variety of reference genomes of various qualities and phylogenetic distance. We show that our method is 100% accurate when mapping to a high-quality (highly contiguous N50 > 30 Mb) conspecific genome, even down to 1000 mapped reads. For lower-quality reference assemblies (N50 < 30 Mb), our method is 100% accurate with 50,000 mapped reads, regardless of reference assembly quality or phylogenetic distance. The SeXY pipeline provides several advantages over previously implemented methods; SeXY (i) requires sequencing data from only a single individual, (ii) does not require assembled conspecific sex chromosomes, or even a conspecific reference assembly, (iii) takes into account variation in coverage across the genome, and (iv) is accurate with only 1000 mapped reads in many cases.

Estimation of sex from computed tomography images of skull measurements in an adult Turkish population

BACKGROUND

Nowadays, data on the anthropometric measurements of populations is needed in many areas, especially forensic and legal. Using various methods, researchers obtain various data such as race, sex, and age, and thus provide identification of the material used. Morphological or metric methods are often used for identification.

PURPOSE

To evaluate the usefulness of the results of skull measurements using computed tomography (CT) to determine sex in a Turkish population.

MATERIAL AND METHODS

We analyzed 300 male and 300 female CT images of Turkish individuals with an age range of 21-50 years. Maximum cranial length, maximum cranial breadth, bimastoid diameter, bizygomatic diameter, and bigonial breadth were measured by CT tomography. All data were subjected to discriminant function analyses for estimating sex. Intra-observer and inter-observer variances of the measurements were examined using intraclass correlation coefficient analysis.

RESULTS

Discriminant function analysis indicated that there was a significant difference between male and female with 88% accuracy. Discriminant function for estimation of sex was obtained with satisfactory accuracy rates for the parameters used.

CONCLUSION

This study confirms that skull measurements show sexual dimorphism in the Turkish population, and also suggests that it may be useful to use CT to assess skull anthropometric measurements.

Alternative LC-MS/MS Platforms and Data Acquisition Strategies for Proteomic Genotyping of Human Hair Shafts

Protein is a major component of all biological evidence. Proteomic genotyping is the use of genetically variant peptides (GVPs) that contain single-amino-acid polymorphisms to infer the genotype of matching nonsynonymous single-nucleotide polymorphisms for the individual from whom the protein sample originated. This can be used to statistically associate an individual to evidence found at a crime scene. The utility of the inferred genotype increases as the detection of GVPs increases, which is the direct result of technology transfer to mass spectrometry platforms typically available. Digests of single (2 cm) human hair shafts from three European and two African subjects were analyzed using data-dependent acquisition on a Q-Exactive Plus Hybrid Quadrupole-Orbitrap system, data-independent acquisition and a variant of parallel reaction monitoring (PRM) on an Orbitrap Fusion Lumos Tribrid system, and multiple reaction monitoring (MRM) on an Agilent 6495 triple quadrupole system. In our hands, average GVP detection from a selected panel of 24 GVPs increased from 6.5 ± 1.1 and 3.1 ± 0.8 using data-dependent and -independent acquisition to 9.5 ± 0.7 and 11.7 ± 1.7 using PRM and MRM (p < 0.05), respectively. PRM resulted in a 1.3-fold increase in detection sensitivity, and MRM resulted in a 1.6-fold increase in detection sensitivity. This increase in biomarker detection has a functional impact on the statistical association of a protein sample and an individual. Increased biomarker sensitivity, using Markov Chain Monte Carlo modeling, produced a median-estimated random match probability of over 1 in 10 trillion from a single hair using targeted proteomics. For PRM and MRM, detected GVPs were validated by the inclusion of stable isotope-labeled peptides in each sample, which served also as a detection trigger. This research accomplishes two aims: the demonstration of utility for alternative analytical platforms in proteomic genotyping and the establishment of validation methods for the evaluation of inferred genotypes.

Contributions of anatomy to forensic sex estimation: focus on head and neck bones

This study sought to provide an up-to-date review of the importance of anatomy to human identification, focusing on the usefulness of anatomical knowledge about the head and neck bones and teeth to sex estimation in routine forensic anthropology methods. A detailed search of osteology applications in forensic sex estimation was conducted through the electronic databases for the 10 years prior to July 2020. Relevant articles and classic literature on the subject were gathered and are outlined in this review. Among the available literature, several metric analyses showed accuracy superior to 80% in sexual diagnosis. Angles measured from the inclination of glabellae and analysis of the external frontal bone surface through three-dimensional computer-aided design emerge as reliable cranial indexes for sex estimation. In the mandible, the condylar and coronoid height, bigonial width, and coronion–gonion distance express significant sexual dimorphism. Measurements of the canine are the best option for sex estimation using teeth, as well as the thickness of the dentine or enamel of incisors. The axis vertebra surpasses other neck bones for sex estimation due to its atypical shape and the presence of the odontoid process. Metric analyses based on anatomy can provide reliable accuracy in sexual diagnosis. Adequate training and anatomical knowledge can reduce bias and interobserver differences, and the use of three-dimensional models and computed tomography images can enhance the accuracy of these methods for sex estimation. However, every method should be validated before being applied to a different population.

Key Points

• Anatomy-based metric analyses can provide reliable accuracy in forensic sex estimation.

• Glabellae inclination, external frontal bone surface, mandible, and canine teeth measurements can reach accuracies superior to 80% in sexual diagnosis.

• The use of three-dimensional models and computed tomography images can enhance accuracy in sex estimation.

• Every method should be validated before being applied to a different population.

Female hunters of the early Americas

Sexual division of labor with females as gatherers and males as hunters is a major empirical regularity of hunter-gatherer ethnography, suggesting an ancestral behavioral pattern. We present an archeological discovery and meta-analysis that challenge the man-the-hunter hypothesis. Excavations at the Andean highland site of Wilamaya Patjxa reveal a 9000-year-old human burial (WMP6) associated with a hunting toolkit of stone projectile points and animal processing tools. Osteological, proteomic, and isotopic analyses indicate that this early hunter was a young adult female who subsisted on terrestrial plants and animals. Analysis of Late Pleistocene and Early Holocene burial practices throughout the Americas situate WMP6 as the earliest and most secure hunter burial in a sample that includes 10 other females in statistical parity with early male hunter burials. The findings are consistent with nongendered labor practices in which early hunter-gatherer females were big-game hunters.

Child murder in the Early Bronze Age: proteomic sex identification of a cold case from Schleinbach, Austria

The identification of sex-specific peptides in human tooth enamel by nanoflow liquid chromatography-tandem mass spectrometry (nanoLC-MS/MS) represents a quantum leap for the study of childhood and social relations more generally. Determining sex-related differences in prehistoric child rearing and mortality has been hampered by the insufficient accuracy in determining the biological sex of juveniles. We conducted mass spectrometric analysis to identify sex-specific peptides in the dental enamel of a child from a settlement pit of the Early Bronze Age settlement of Schleinbach, Austria (c. 1950-1850 bc). Four perimortal impression fractures on the skull of a 5-6-year-old child indicate an intentional killing, with a co-buried loom weight as possible murder weapon. Proteomic analysis, conducted for the first time on prehistoric teeth in Austria, determined the child's sex as male. While we cannot conclusively determine whether the child was the victim of conflicts between village groups or was slain by members of his own community, we suggest that contextual evidence points to the latter. A possible trigger of violence was the follow-on effects of an uncontrolled middle ear infection revealed by an osteological analysis. The boy from Schleinbach highlights the potential for further investigation of gender-biased violence, infanticide and child murder based on the recently developed method of proteomic sex identification.