Genetic sexing to determine the optimal discriminant functions for the analysis of archaeological remains from El Hierro (Canary Islands)

A correct sex assignment of a given bone or bone fragment is of paramount importance for the archaeologist, anthropologist and in forensic medicine. Discriminant functions, combining several anthropometric measurements obtained from individuals with known sex are useful tools for this purpose, but it is essential to know exactly the sex from which the measures are obtained. This is an easy task in modern populations, but it is problematic in ancient ones, since even when the entire skeleton is available, diagnosis of sex is not 100% accurate. Sexing by genetic methods by amplifying the first intron of the amelogenin gene constitutes a much more accurate method for sexing bones and may be the gold standard for further elaboration of discriminant functions which may serve for sexing new bones dug up in future excavations. With this aim we have genetically sexed 52 (out of 59) tibiae belonging to the prehispanic population of El Hierro, in the Canary Islands, identifying 18 women and 34 men, and then, performed discriminant functions combining several anthropometric variables. These functions show a high accuracy in sex diagnosis (94.2%; area under ROC curve = 0.954 with the best of the functions), so that they allow correct sexing of tibiae or tibiae fragments (only proximal third, distal third or midshaft). Thus, genetic sexing obviates the problem of finding an accurate gold standard for the elaboration of discriminant functions for ancient bones. This method could be applied to other populations of different antiquity and different ethnicity.     

The Meul Index: A non‐destructive method for estimating the cortical index in skeletal samples

The study of osteoporosis in past populations provides insight into the history and evolution of this condition. The Cortical Index is a relative measure of cortical bone often used for identifying individuals with age‐related bone loss associated with osteoporosis. Current methods of measuring the Cortical Index involve radiography or cutting actual sections of long bones at the mid‐shaft. We propose a new index, the Meul Index as means for estimating the Cortical Index without the use of radiography. Based on a preliminary study of 13 individuals consisting of 9 males, 3 females and one unknown sex, ranging in age from young to older adult, the Meul Index is highly correlated with the Cortical Index (r = 0.903). The proposed Meul Index provides a non‐destructive and inexpensive means for studying age‐related bone loss in prehistoric and historic populations represented by skeletal samples. Our research builds on the recent publication of Silva, A.M., Crubezy, E. and Cunha, E. 2008. Bone weight: new reference values based on a modern Portuguese identified skeletal collection. Int. J. Osteoarchaeol. DOI: 10.1002/oa.998. Copyright © 2009 John Wiley & Sons, Ltd.     

An exploration of character traits and linear measurements for sexing mountain gazelle (Gazella gazella) skeletons

The skeletal elements of mountain gazelle (Gazella gazella) have proven difficult to sex with statistical confidence due to wide overlap in the body size of the two sexes. We studied a sample of 53 modern mountain gazelle skeletons to determine which character traits and metric measurements best predict sex. The success of the character traits was determined using blind tests while the metrics were examined using discriminant function analysis. The most useful elements include the previously identified horn core, pubis and atlas, but also some new bone portions that preserve well in the archaeological record (e.g., distal tibia, distal metacarpal and metatarsal, and second phalanx). Surprisingly, two elements commonly used in sexing analyses (distal humerus and astragalus) were not among the most effective elements. Although cutting points and discriminant functions for sexing gazelle bone portions are presented here, they do not account for potential body size change and thus are not suited for direct application to archaeological assemblages. Instead, we provide guidelines for application to archaeological gazelle assemblages, most importantly a regression analysis that considers the sex ratios obtained from multiple measurements to predict the sex ratio of archaeological gazelle populations.     

Thalassemia: macroscopic and radiological study of a case

Differentiation of the genetic and the acquired anaemias, particularly in areas of the world where they may co‐exist, has been a challenge for palaeopathologists for over 100 years. In this paper we present macroscopic and radiographic skeletal lesions that are associated with the thalassemias in a 14‐year‐old girl from a modern reference collection of the University of Athens. This individual is of known sex, age, cause of death, place and dates of birth and death. The case is examined in terms of epidemiology, growth, distribution and severity of lesions and differential diagnosis. The entire skeleton is affected by marrow hyperplasia: lesions of the axial skeleton are extreme, and the appendicular skeleton is severely affected as well. The odontofacial manifestations that are diagnostic of thalassemia and differentiate it from other anaemias are present and include: maxillary and mandibular hyperplasia, reduced sinuses, displacement of maxillary dental structures, overbite, and generalised osteopenia. The development of extreme bone lesions and the ‘advanced’ age‐at‐death of this individual is explained as either the result of thalassemia major under a low transfusion regimen that was the norm during her lifetime, or to a form of thalassemia intermedia that allows survival to later life at the expense of gross skeletal alterations. The present status of skeletal studies in Greece does not support the identification of a genetic anaemia in past populations. The potential contribution of the current analysis in differentiating the anaemias in antiquity is evaluated. Copyright © 2006 John Wiley & Sons, Ltd.     

The demographic,socio‐economic and temporal contextualisation of the Universitat Autònoma de Barcelona collection of identified human skeletons (UAB collection)

Identified human skeletal collections are those in which basic demographic data (sex, age and biological origin) are known and are crucial for developing and testing osteological methodologies. It is important that the identified collection be contextualised, and in this way the collection will be considered a reference collection. To contextualise a collection requires documentation of the basic demographic data of the individuals (sex, age, year of birth, geographical area) as well as information concerning the socio‐economic and temporal context in which the individuals lived. The contextualisation of an identified collection is very important so the researchers can understand the ‘point of reference’ when applying a method to it or developing a new method. The purpose of this study is to contextualise the identified skeletal collection of the Universitat Autónoma de Barcelona (UAB) which currently contains 35 adult skeletons of both sexes. To carry out the objectives of the present study, the information about the individuals was collected from cemetery registers and compared with the information of the demographic and statistic public institutions of Spain. The results indicate that the UAB collection is formed only by Spanish nationals who mainly lived during the 20th century in Granollers (Barcelona, Spain). Both sexes are equally represented and all of the individuals are adults. They reflect the most current adult population structure of Catalonia and be treated as a Catalan reference sample of adults living in the 20th century. This collection offers special opportunities for demographic analysis, including validation studies of skeletal ageing and sexing methods that target adult individuals. The collection can also be used in conjunction with other reference samples to investigate secular and populational change in cranial form, sexual dimorphism and stature. Copyright © 2010 John Wiley & Sons, Ltd.     

Sexual dimorphism in limb bones of ibex (Capra ibex L.): mixture analysis applied to modern and fossil data

Estimating sex ratios of fossil bone assemblages is an important step in the determination of demographic profiles, which are essential for understanding the palaeobiology and palaeoethology of any particular species, as well as its exploitation patterns by humans. This is especially true for ibex (Capra ibex), which was a main source of food for hominids during Pleistocene times. Classical methods for determining sexual dimorphism and sex ratio, such as analyses using uni‐ and bivariate plots, are based on an arbitrary fixing of limits between sexes. Here we use a more robust statistical method termed mixture analysis (MA) to determine the sex of postcranial remains (long bones, metapodials and tarsals) from ibex. For the first time, we apply MA to both a modern and a fossil sample of one species, by using metric data taken from (i) a collection of present‐day ibex skeletons and (ii) a Palaeolithic sample of the same species. Our results clearly show that the forelimb (humerus and radius) is more dimorphic than the hindlimb (femur and tibia) and is therefore better suited for sexing ibex. It also appears that metapodials should be used carefully for estimating sex ratios. On the basis of these results, we propose a classification of bone measurements that are more or less reliable for sexing ibex. The results of MA applied to the ibex fossil bones from the Upper Palaeolithic site of the Observatoire (Monaco) lead us to the conclusion that this assemblage consists of a majority of males. The quantitative estimations calculated by the MA make it possible to compare the size of Pleistocene and modern ibex for the whole set of variables used in this study. Copyright © 2006 John Wiley & Sons, Ltd.     

Scars of Parturition? Influences Beyond Parity

In the 40 years since the phrase ‘scars of parturition’ was coined, studies have attempted to show the relationship between scars on the bony pelvis and parity history. Despite numerous studies, the relationship of parity and scarring remains unclear. The challenge facing these studies is the rarity of skeletal collections of known parity. The alternative study approach is examining relationships between scars and factors other than pregnancy‐related strains that may affect their manifestation. Skeletal remains of 312 individuals were examined for scarring at the dorsal pubic surface, pubic tubercle, preauricular sulcus, interosseous groove and iliac tuberosity. Pelvic and femoral measurements were also taken. Features were compared according to sex and age. Principal components analysis was performed to assess the influence of body and pelvic size on scar manifestation. Scars occurred in both sexes, although they were more common and more severe in females. Scar severity remained unchanged or increased with age in both sexes. Females had smaller bodies but larger pelves than males. The interspinous and transverse inlet diameters and the femur measurements increased with age. Principal components analysis showed that body and pelvic sizes represented the majority of the observed variation, with scars occurring more commonly in small‐bodied individuals with large pelves, most of which were females. Both sexes also show a difference in the magnitude of scarring at the pubis and ilium. These results suggest that weight‐bearing and pelvic stability may be a better explanation for scarring than parturition‐related strain. Female pelves are more flexible and require more ligamentous stabilization, causing increased scar formation. The weight‐bearing strain on male pelves may sometimes also be sufficiently large to cause similar scars. Future studies may be able to test this theory on samples of known parity history. Copyright © 2014 John Wiley & Sons, Ltd.     

Age‐Related Cortical Bone Maintenance and Loss in an Imperial Roman Population

This article explores age‐ and sex‐related patterns of cortical bone loss, assessed by radiogrammetry of the second metacarpal, from a skeletal sample excavated from the Imperial Roman port city of Velia (1st and 2nd century ad ), to contribute to our understanding of health and disease during the Imperial period. Patterns of age‐ and sex‐related bone loss and health at Velia are also compared with other historical samples and to modern clinical data. It was hypothesised that patterns of age‐ and sex‐related bone loss in this well‐represented Roman sample (n = 71) would mirror those reported in modern populations. Differences in the quantity of cortical bone between three age groups (18–29, 30–49 and 50+ years) are significant in both men and women; however, the pattern of bone loss differs between the sexes. Women show a gradual decline in bone quantity beginning in middle age, whereas men only lose bone in old age. However, there are no significant sex differences at any age group in the metacarpal cortical index. These findings suggest the hypothesis should be refuted because significant sex differences, particularly in old age, are an expected hallmark of bone loss in Western populations today. The possible biocultural and gender‐related factors that may have contributed to the observed patterns of bone maintenance and loss at Velia are discussed. Copyright © 2011 John Wiley & Sons, Ltd.     

Osteometric and molecular sexing of cattle metapodia

Sex identification of skeletal remains based on morphology is a common practice in Zooarchaeology. Knowledge of the sex distribution of slaughtered or hunted animals may help in the interpretation of e.g. hunting or breeding strategies. Here we investigate and evaluate several osteometric criteria used to assess sex of cattle (Bos taurus) metapodia using molecular sex identification as a control of the metric data. The bone assemblage used to assess these new criteria derives from the Eketorp ringfort in the southern parts of Öland Island in Sweden. One hundred metapodia were selected for molecular analysis of sex and we were able to genetically identify the sex of 76 of these elements. The combined results of the molecular and osteometric analyses confirm a significant size difference between females and males for several measurements for both metacarpals (Mc) and metatarsals (Mt). Our results show that some measurements are applicable for metapodials. These measurements include the slenderness indices such as the Mennerich’s index 1 and 3, as well as the distal breadth (Bd), the breadth between the articular crests (Bcr), and the maximum breadth of the lateral trochlea (BFdl). We show that they can be used for sexing of both metacarpals and metatarsals. The latter measurements offer an opportunity to study fragmented elements and thus a higher number of elements may be utilized for morphological sexing of archaeological bones. Size comparisons of Mc and Mt may also aid in the separation of bulls and oxen.     

Further developments in molecular sex assignment: a blind test of 18th and 19th century human skeletons

The identification of sex in human remains recovered from archaeological locations is important in order to understand the social and biological structure of past societies, and to reconstruct past population demographic events. Sex determination is usually based on morphological traits of the skeletons, with the drawback that most methods do not apply to juveniles and require well preserved remains. In cases where morphological methods cannot be used, or are ambiguous, methods of molecular sexing systems are an alternative. In this methodological study we tested and validated the accuracy and usefulness of a molecular sexing method based on the amelogenin gene using pyrosequencing. We did this in a double blind study of documented 18th and 19th century human remains.     

A Neolithic Case of Mesomelic Dysplasia from Northern Switzerland

Paleopathological cases of skeletal dysplasias (SD) are particularly interesting from a biological as well as biocultural perspective. Evidence of SD is relevant when discussing the antiquity of specific mutations, as well as the social perception of disease in the past. Here we propose a differential diagnosis for a Neolithic case of SD and discuss the possible social correlates of the observed condition. The subject of this study, a child with an age at death of about 12 years from the Late Neolithic site of Schweizersbild (Northern Switzerland), presents a bilateral shortening of the forearm and lower leg, with no further modifications affecting the cranial and postcranial skeleton. Morphological, metric, as well as radiographic analyses point to a diagnosis of Léri Weill dyschondrosteosis (LWD), making the present case the earliest known paleopathological example of this condition. From a biocultural perspective, the skeletal changes affecting the child, together with her/his relatively advanced age, suggest active support from the community, providing new data to inform the debate on the cultural dimensions of disease in prehistory. Copyright © 2013 John Wiley & Sons, Ltd.     

Skeletal and Surgical Evidence for Acute Osteomyelitis in Non‐Adult Individuals

Osteomyelitis is a non‐specific infection of the bone and bone marrow. In the past acute osteomyelitis (AO) led to high mortality especially in non‐adults. Nevertheless, its diagnosis in archaeological populations is rare. Documented individuals with known cause of death offer a unique opportunity to study this condition. This article aims to describe the bone lesions in non‐adults diagnosed with AO at the Coimbra University Hospital (CUH) and now belonging to the Coimbra Identified Skeletal Collection (CISC). Moreover, mortality rates and demographic profiles for individuals aged ≤18 years old and diagnosed with AO in the CUH, between 1923 and 1929, were also determined. The 5 (1%) non‐adults in the CISC with AO listed as cause of death were selected for this study, and their bones were analysed macroscopically and radiologically. The skeletal remains of one individual revealed a small area of new bone formation in the shaft of the left femur. Radiography of this bone showed a radio‐opaque area in the diaphysis. The other four individuals show evidence of surgical treatment, responsible for many cases of disability in the past. In the 7‐year period under analysis, 122 juveniles were diagnosed with osteomyelitis and admitted for surgery at the CUH, 43 (35.2%) of which were diagnosed with AO. Sixty‐five per cent of the cases of AO occurred between the ages of 8 and 15 years, with boys twice as frequently affected as girls, and lower limb bones were involved in 91% of AO cases. AO was responsible for 76.9% of the deaths. This study of pre‐antibiotic non‐adults may help to recognize skeletal signs of AO and their surgical treatment in unidentified skeletal remains. Copyright © 2012 John Wiley & Sons, Ltd.     

DNA FROM HUMAN ANCIENT BACTERIA: A NOVEL SOURCE OF GENETIC EVIDENCE FROM ARCHAEOLOGICAL DENTAL CALCULUS

We report a molecular methodology to obtain and analyse ancient bacterial DNA from archaeological dental calculus. Recent and archaeological DNA samples, as old as 4000 bp , were successfully extracted and amplified with species‐specific PCR primers. We propose this approach in order to: detect the presence of specific bacterial species infecting past human populations; compare the composition of ancient oral microbiomes among human populations; and analyse the genetic variability and covariation of bacteria and human host populations. Genomic analysis of bacteria from dental calculus is a promising source of evidence for palaeopathological and micro‐evolutionary studies, focused either on micro‐organisms or their human hosts.     

Sexing cattle horn‐cores: problems and progress

It has long been recognised that cattle horn‐cores are sexually dimorphic, and many methods have been developed using archaeological material for differentiating between specimens belonging to cows, bulls and oxen. Whilst these techniques have been adopted widely by zooarchaeologists, in particular those studying medieval and post‐medieval tannery and horn‐working assemblages, they are highly subjective and their reliability has never been tested using material from cattle of known sex. This paper seeks to redress the balance. It presents the results of a study of 19th and 20th century cattle horn‐cores, from animals of known age, sex and breed, which were examined and measured in order to test the validity of traditional horn‐core sexing techniques. Previously claimed traits of sexual variation are here refuted, and a new metrical threshold for separating the males and females of ‘medium‐horned’ and ‘long‐horned’ types are presented. Copyright © 2007 John Wiley & Sons, Ltd.     

Diameter of the human internal acoustic meatus and sex determination

We report the results of testing the diameter of the internal opening of the acoustic canal in the petrous part of the temporal bone for sex determination of skeletal remains. The method involves measuring the diameter using a suite of ordinary drills. The method is very simple and has the great advantage of utilising one of the sturdiest bone elements of the human skeleton. The method may be especially useful for the analyses of very fragmented skeletal remains or cremated bones, where the petrous bone may still be readily recognisable. The method was tested using a forensic sample of 113 left petrous bones with known sex. Intra‐ and inter‐observer testing was also performed. We found a statistically significant difference in diameter between males and females (means: males: 3.7 mm; females: 3.4 mm; P < 0.009). However, the low predictive value (70%) for correct sexing using two sectioning points ( < 3.0 mm = female; >3.5 mm = male) was disappointing. No additional accuracy was gained by employing both left and right petrous bones (a bilateral sample of 60 petrous bones was also tested), although left and right side diameter is highly correlated (R = 0.778; P = 0.0001). Copyright © 2005 John Wiley & Sons, Ltd.     

The Occurrence and Possible Aetiology of Spondylolysis in a Pre‐contact California Population

The occurrence of spondylolysis (neural arch separation at the pars interarticularis) is reported in a pre‐contact (720–550 Cal BP) Central California population, CA‐CCo‐647 (n = 46). Spondylolysis was examined within this population to assess differences in sex, age, and possible relationships with biological affinity. Furthermore, prevalence rates of spondylolysis were compared across various populations to discern the aetiology of the defect. Within CA‐CCo‐647, spondylolysis was found in 17.4% (8/46) of the population. All occurrences are complete, bilateral separations of the neural arch in the lower lumbar (L4 and L5). The defect is not seen in individuals below the age of 18, and there is no correlation between adult age and spondylolysis. Male individuals display the defect at a higher rate (30.8% ‐ 4/13) than female individuals (12.1% ‐ 4/33); however, this is not a statistically significant finding. There does seem to be a correlation between an individual's sex and the onset of the defect; male individuals display spondylolysis at a younger age than female individuals. This finding could represent differences in activity patterns among young male and female individuals. In a biological distance analysis using craniometric data, male and female individuals with spondylolysis clustered closely, suggesting a genetic component for the defect. Finally, significant differences were found in spondylolysis prevalence between various populations representing distinct geographic and temporal settings. Significant differences were found among Native pre‐contact samples and even between two comparable pre‐contact California skeletal samples. These populations all engaged in distinct activities and were likely composed of genetically distinct groups of individuals, which may account for the differences in spondylolysis prevalence. All of these findings, both within CA‐CCo‐647 and between the various samples, suggest that the aetiology of spondylolysis is likely an interaction of genes and activity. Copyright © 2012 John Wiley & Sons, Ltd.     

Don't throw out the baby with the bathwater: Estimating fertility from subadult skeletons

Recent research interest has focused on the bioarchaeology of children. Although paleodemography is essential for accurate reconstructions of lifestyle and health in past populations, currently there is no published technique for estimating fertility and life expectancy at birth for skeletal populations in which adults are under‐enumerated. This paper provides a formula to predict Gross Reproductive Rate (GRR) from the proportion of young infants to subadults in a skeletal population. The formula was developed from 98 of Coale and Demeny's Female Model West Life Tables, which represented diverse fertility and mortality rates. The formula's accuracy was examined using independent samples from historical and archaeological cemeteries. Estimates of GRR from the subadult fertility formula were compared with estimates from Bocquet‐Appel and Masset's juvenile:adult ratio. Results indicate that the subadult fertility formula predicts GRR with consistent accuracy (R² = 0.98) and precision (± 1 offspring) in the model life tables, across diverse subadult age structures and demographic characteristics. The formula is useful for subadult populations with a proportion of perinates:subadults between 0.12 and 0.45. The adult component of the sample is not included in the analysis and thus the formula is similarly useful in cases where adults are under‐enumerated, or not. When applied to historical and archaeological populations, estimates for GRR are similar to previous estimates from the juvenile:adult ratio. Because crude birth rate and life expectancy at birth can be calculated from GRR using established fertility centred approaches to demography, the subadult fertility formula allows skeletal populations of diverse composition to be included in demographic research, essential for understanding of how mortality and fertility are affecting the morbidity profiles of subadult samples and for comparative bioarchaeological analyses. Copyright © 2010 John Wiley & Sons, Ltd.     

Degenerative Joint Disease and Social Status in the Terminal Late Archaic Period (1000–500 b.c.) of Ohio

This research presents an analysis of the inferred Late Archaic social structure in Ohio based on degenerative joint disease (DJD, also known as osteoarthritis) and mortuary practices. We tested the hypothesis that mechanical loading involving physical activities is differentially distributed in a population along levels or types of social stratification. This hypothesis was investigated via statistical treatment of DJD as a skeletal stress marker of activity, its occurrence by age and sex, an association with grave goods, and spatial distribution in terminal Late Archaic cemeteries. The skeletal samples used in this study came from three cemeteries, the Boose, Kirian‐Treglia (KT), and Duff sites, dating to the Ohio terminal Late Archaic period. In general, the high overall prevalence of DJD in these people indicates that this population led a rigorous life. This study hypothesized that the burials in the Late Archaic period in Ohio might be socially patterned as evidenced from the unequal distribution of grave goods and skeletal variability in DJD. Nevertheless, the analyses suggest that there is no statistical association between DJD and mortuary practices including grave goods and burial location in a cemetery. As observed in numerous hunter–gatherer populations, the societies in our sample were also characterized by the absence of a marked social stratification. The results suggest that there were only ‘natural inequalities’ in Late Archaic societies due to biological factors, such as age and sex. Copyright © 2011 John Wiley & Sons, Ltd.     

On the accuracy of estimating living stature from skeletal length in the grave and by linear regression

This study evaluates a method for obtaining stature estimates for populations represented by skeletal material, with individuals buried in a supine position. During the excavation of a Danish mediaeval cemetery, in situ skeletal length in the grave was measured from a point above the cranial point farthest from the body to the most distal point of the talus. The measurement was made with a folding rule placed on the sagittal midline of the skeleton, allowed to follow any curvature of the skeleton in situ. In the laboratory, stature was reconstructed anatomically, and this stature was regarded as an accurate estimate of living stature. Stature was also reconstructed from femur length by two linear regression procedures: 1) by sample and sex specific formulae, employing a leave‐one‐out approach, and 2) by sex wise formulae for Euro‐Americans from Trotter & Gleser (1952, American Journal of Physical Anthropology 10 : 463–514). Skeletal length in the grave and the two stature estimates based on linear regression were compared to anatomically reconstructed stature. Skeletal length in the grave estimated anatomically reconstructed stature with practically no bias (95% CI: −1.3–1.5 cm). Sample specific regression formulae estimated anatomically reconstructed stature also with no bias (95% CI: −1.2–1.1 cm). In contrast, statures calculated from Trotter & Gleser's regression formulae estimated anatomically reconstructed stature with a bias of about 4 cm (95% CI: 3.3–5.0 cm). Estimates of stature variance were biased for all three estimation procedures. However, for samples of adults, an adjusted variance estimate can be obtained by subtracting 8.7 cm² from the variance obtained from skeletal lengths in the grave. It is recommended to measure skeletal length in the grave whenever possible, and use this measurement for estimating statures for prehistoric and early historic populations. Copyright © 2005 John Wiley & Sons, Ltd.