Inferring the mobility of a middle Upper Paleolithic female skeleton from Caviglione (Liguria, Italy): Impact of trauma and mountainous terrain.

Mobility and territory occupation, the participation of injured individuals in group activities, and the role of women in early human groups are crucial issues in human evolution. Previously, a biomechanical study showed evidence of several traumas to the upper limb of the well-preserved middle Upper Paleolithic (UP) female skeleton from Caviglione (Caviglione 1, Liguria, Italy) but did not characterize their impact on locomotor behavior. Furthermore, mobility in the European UP context is thoroughly documented in males but not in females. Therefore, we examined whether this trauma-affected female skeleton shows bone adaptation to high mobility, as expected in UP groups, and to frequent foot eversion and inversion, as expected, given the mountainous area in which it was discovered. This study investigated the structural properties of the femur, tibia, fibula, and first metatarsal to infer the mobility level and pattern of Caviglione 1. We analyzed the diaphyseal 'shape', robusticity, fibular cortical distribution, and relative robusticity (fibula versus tibia). No substantial findings were derived from the first metatarsal. The fibular cortical distribution can discriminate 'active' (nomadic or settled) and recent sedentary human groups; these findings indicated Caviglione 1 belonged to the former. Interestingly, compared with ancient and recent sedentary humans and some UP individuals, Caviglione 1 had femurs with strong relative anteroposterior rigidity and robust tibias and fibulas reflecting an adaptation to extremely high levels of mobility. The very high relative fibular robusticity of Caviglione 1, higher than that of Middle UP males, is consistent with bone adaptation to frequent travel through mountainous terrain. Such fibular robusticity may also be a consequence of imbalance, due to upper limb traumas, when traveling downhill. These findings indicate that injured individuals may have participated in subsistence activities in past populations and describe an UP female with bone adaptations to habitual high mobility, notably in mountainous terrain.

Early ontogeny of humeral trabecular bone in Neandertals and recent modern humans.

Trabecular bone ontogeny is well known in modern humans and unknown in Neandertals. Yet the bone developmental pattern is useful for interpreting fossils from evolutionary and functional perspectives. Interestingly, microstructure in early ontogeny is supposedly not influenced by high and specific mechanical loading related to the lifestyle of a human group and consequently does not directly depend on the activities of hunter-gatherers. Here, we specifically explored the early growth trajectories of the trabecular bone structure of the humerus and emphasized in particular how bone fraction (bone volume/total volume [BV/TV]) was built up in Neandertals, given the specific modern human bone loss after birth and the use of BV/TV in functional studies. Six Neandertals and 26 recent modern humans ranging from perinates to adolescents were included in this study. Six trabecular parameters were measured within a cubic region of interest extracted from the proximal metaphysis of the humerus. We found that the microstructural changes in Neandertals during early ontogeny (<1 year) fit with modern human growth trajectories for each parameter. The specific bone loss occurring immediately after birth in modern humans also occurred in Neandertals (but not in chimpanzees). However, the early childhood fossil Ferrassie 6 presented unexpectedly high BV/TV, whereas the high BV/TV in the Crouzade I adolescent was predictable. These results suggest that Neandertals and modern humans shared predetermined early growth trajectories and developmental mechanisms. We assume that the close relationship between skeletal characteristics in early ontogeny and adults in modern humans also existed in Neandertals. However, it was difficult to ensure that the high BV/TV in Neandertal early childhood, represented by only one individual, was at the origin of the high BV/TV observed in adults. Consequently, our study does not challenge the mechanical hypothesis that explains the trabecular gracilization of the humerus during the Holocene.

Age-related site-specific modifications in diaphyseal structural properties of the human fibula: Furrows and cross-sectional geometry.

OBJECTIVES: Fibular structure is related to locomotor behavior, which allows an exploration of mobility in past human populations with diaphyseal cross-sectional geometry (CSG). However, bone structure depends on age-related changes. Nonmechanical alterations can affect biomechanical investigations. In this study, we examined how the cortical area and the variables used as functional markers in the fibular diaphysis (i.e., CSG and furrows) change with aging. We predict classic and specific modifications, and we discuss functional interpretations based on bone structure. MATERIALS AND METHODS: The sample consisted of 124 individuals of known age in whom the fibular furrow depths were measured with calipers. Microcomputed tomography (micro-CT) scanning of 38 individuals provided CSG (e.g., cortical area, shape index, and robusticity) and fibular furrow indices. CSG was studied at five cross sections taken along the diaphysis. Linear regression analyses and age group comparisons were conducted. RESULTS: The cross-sectional shape summary by fibular furrows and shape index and the total area did not change with aging; in contrast, the cortical area and the robusticity (Zp-std) decreased with age. DISCUSSION: The decrease in robusticity (Zp-std) with aging is due to the maintenance of total area, which is related to the specific mechanical environment of the fibula, and to the loss of cortical bone and not to the decrease in mechanical stress. This finding is consistent with the lower bone modeling capacity in aged individuals, which also explains the lack of significant changes in the diaphyseal shape. Thus, fibular structure in older individuals is due to a combination of early bone adaptations to stress and aging effects.

Trauma in the upper limb of an Upper Paleolithic female from Caviglione cave (Liguria, Italy): Etiology and after-effects in bone biomechanical properties.

The impact of injury on the health and activities of human foragers is of great interest for understanding the adaptability of past populations to their environments. For the Gravettian female of Caviglione 1, a violent blow has been suggested as the origin of the left radial fracture, and abnormal body asymmetry has been observed. Access to high resolution CT-scans of the upper limb allows us to address new etiologic considerations and assess the after-effects of trauma on bone biomechanical properties by focusing on cortical and trabecular bones and conducting a comparative analysis of cross-sectional geometric properties in an Upper Paleolithic context. This originally right-dominant female, who became left-handed, was mainly affected by severe bone modifications on the proximal right humerus due to secondary changes following a traumatic event. The left radial fracture is very well consolidated with thick and homogeneous cortical bone. Etiological considerations point to a Galeazzi fracture for the left forearm occurring during a fall. The bone structure and robusticity of the left arm probably prove the lack of strong and enduring dependency of this female on her group for the usual cultural tasks despite the strongly limited function of the right arm.

Neandertal features of the deciduous and permanent teeth from Portel-Ouest Cave (Ariège, France).

OBJECTIVES: We describe 14 unpublished and nine published teeth from the Mousterian level of Portel-Ouest (Ariège, France), dated to 44 ka. In a comparative context, we explore the taxonomical affinities of those teeth with Neandertals and modern humans which are both known to exist at that time. We further make some paleobiological inferences about this human group. METHODS: The comparative analysis of Neandertals and modern humans is based on nonmetric traits at the outer enamel surface and the enamel-dentine junction, crown diameters and three-dimensional (3D) enamel thickness measurements of lower permanent teeth. The crown and roots are explored in detail based on the µCT-scan data to identify the multiple criteria involved in the paleobiological approach. RESULTS: Nonmetric traits and 3D enamel thickness tend to be more similar to Neandertals than modern humans, notably for C1 , P4 , and M2 (included in all analyses) as well as volume of the pulp cavity in roots of the anterior permanent teeth. The Portel-Ouest sample corresponds to a minimum of seven juveniles, one or two adolescents and one adult, which exhibit recurrent linear enamel hypoplasia (up to five events for one individual), the torsiversion of one anterior tooth and irregular oblique wear in some anterior deciduous teeth. DISCUSSION: This morphological study confirms that the remains from Portel-Ouest are Neandertals, associated with a Mousterian complex. Furthermore, we found the expected pattern of mortality and stress for a Neandertal group, that is, various age categories and developmental defects (nonexclusive to Neandertals), while adults are underrepresented and juveniles are overrepresented. Further excavations would contribute finding new remains and maybe complete this demographic profile.

Body mass prediction from femoral volume and sixteen other femoral variables in the elderly: BMI and adipose tissue effects.

OBJECTIVES: The frequently used prediction equations of body mass do not seem appropriate for elderly individuals. Here, we establish the relationship between femoral dimensions and known body mass in elderly individuals in order to develop prediction formulas and identify the factors affecting their accuracy. MATERIALS AND METHODS: The body mass linear least-squares regression is based on 17 femoral dimensions, including femoral volume, and 66 individuals. Body proportion and composition effects on accuracy are analyzed by means of the body mass index (BMI) and on a subset sample (n = 25), by means of the masses of adipose, bone and muscle tissues. RESULTS: Most variables significantly reflect body mass. Among them, six dimensions (e.g., biepicondylar breadth, femoral volume, and head femoral diameter) present percent standard errors of estimate ranging from 9.5 to 11% (r = 0.72-0.81) in normal BMI samples. Correlations are clearly lower in samples with normal and abnormal BMI [r = 0.38-0.58; % of standard error of estimate (SEE) = 17.3-19.6%] and not significantly correlated in females (femoral volume) who present high proportions of abnormal BMI and adipose tissue. In the subset, femoral volume is well correlated with bone mass (r = 0.88; %SEE = 7.9%) and lean body mass (r = 0.67; %SEE = 17.2%). DISCUSSION: Our body mass estimation equations for elderly individuals are relevant since relatively low correlations are recurrent in studies using younger individuals of known body mass. However, age, sex, lifestyle, and skeleton considerations of studied populations can provide information about the relevance of the body mass estimation, which is dependent on the BMI classification and the proportion of adipose tissue. Our general considerations can be used for studies of younger individuals.

The accuracy of body mass prediction for elderly specimens: Implications for paleoanthropology and legal medicine.

Different practices in paleoanthropology and legal medicine raise questions concerning the robustness of body mass (BM) prediction. Integrating personal identification from body mass estimation with skeleton is not a classic approach in legal medicine. The originality of our study is the use of an elderly sample in order to push prediction methods to their limits and to discuss about implications in paleoanthropology and legal medicine. The aim is to observe the accuracy of BM prediction in relation to the body mass index (BMI, index of classification) using five femoral head (FH) methods and one shaft (FSH) method. The sample is composed of 41 dry femurs obtained from dissection where age (c. 82 years) and gender are known, and weight (c. 59.5 kg) and height are measured upon admission to the body leg service. We show that the estimation of the mean BM of the elderly sample is not significantly different to the real mean BM when the appropriate formula is used for the femoral head diameter. In fact, the best prediction is obtained with the McHenry formula (1992), which was based on a sample with an equivalent average mass to that of our sample. In comparison, external shaft diameters, which are known to be more influenced by mechanical stimuli than femoral head diameters, yield less satisfactory results with the McHenry formula (1992) for shaft diameters. Based on all the methods used and the distinctive selected sample, overestimation (always observed with the different femoral head methods) can be restricted to 1.1%. The observed overestimation with the shaft method can be restricted to 7%. However, the estimation of individual BM is much less reliable. The BMI has a strong impact on the accuracy of individual BM prediction, and is unquestionably more reliable for individuals with normal BMI (9.6% vs 16.7% for the best prediction error). In this case, the FH method is also the better predictive method but not if we integrate the total sample (i.e., the FSH method is better with more varied BMI). Finally, the estimation of the mean BM of a sample can be used with more confidence compared to the estimation of individual BM. The former is very useful in an evolutionary perspective whereas the latter should be used in keeping with the information gathered on the studied specimen in order to reduce prediction errors. Finally, the BM estimation can be a parameter to consider for personal identification.

The endostructural pattern of a middle pleistocene human femoral diaphysis from the Karain E site (Southern Anatolia, Turkey).

OBJECTIVE: The human femur from Karain E Cave (Turkey) exhumed from a Mousterian level provided the opportunity to make an incursion into the structural morphology of a late adolescent, or a young adult, femoral shaft from the late Middle Pleistocene of Anatolia. METHODS: Considering the chrono-ecogeographical context, this study focuses particularly on the endostructural morphological similarities between Karain and Neanderthal fossils. RESULTS: Comparative analysis shows that some femoral features of the Karain specimen are frequently observed in Neanderthals, in comparison to some Middle Pleistocene Homo and Middle/Upper Paleolithic modern humans. In particular, we note a high degree of circularity and a strong midshaft posteromedial reinforcement of cortical thickness on the medial side. According to the mapping of cortical thickness, this latter feature can be related to the medial spiral distribution pattern of cortical thickness in the mid-proximal shaft, which is present at Karain and in all Neanderthals available for this study. This spiral distribution was not identified in recent modern humans and may be absent from ancient Homo with femoral pilaster. CONCLUSIONS: The endostructural signature of Karain could indicate a similar biomechanical strain system to that of Neanderthals that could be linked to body shape. However, the presence of posteromedial reinforcement in Berg Aukas may point to an ancestral feature and may be independent of latitude. A larger comparative sample should further clarify the taxonomical, biomechanical, and chrono-ecogeographical origins of the structural femoral features observed in an evolutionary Neanderthal context from MIS 7-9 in Karain.

Characterization of the GATC regulatory network in E. coli.

BACKGROUND: The tetranucleotide GATC is methylated in Escherichia. coli by the DNA methyltransferase (Dam) and is known to be implicated in numerous cellular processes. Mutants lacking Dam are characterized by a pleiotropic phenotype. The existence of a GATC regulated network, thought to be involved in cold and oxygen shift, had been proposed and its existence has recently been confirmed. The aim of this article is to describe the components of the GATC regulated network of E. coli in detail and propose a role of this network in the light of an evolutionary advantage for the organism. RESULTS: We have classified the genes of the GATC network according to the EcoCyc functional classes. Comparisons with all of E. coli's genes and the genes involved in the SOS and stress response show that the GATC network forms a group apart. The functional classes that characterize the network are the Energy metabolism (in particular respiration), Fatty acid/ Phospholipid metabolism and Nucleotide metabolism. CONCLUSIONS: The network is thought to come into play when the cell undergoes coldshock and is likely to enter stationary phase.The respiration is almost completely under GATC control and according to our hypothesis it will be blocked at the moment of coldshock; this might give the cell a selective advantage as it increases its chances for survival when entering stationary phase under coldshock. We predict the accumulation of formate and possibly succinate, which might increase the cell's resistance, in this case to antimicrobial agents, when entering stationary phase.

The difficult interpretation of transcriptome data: the case of the GATC regulatory network.

Genomic analyses on part of Escherichia coli's chromosome had suggested the existence of a GATC regulated network. This has recently been confirmed through a transcriptome analysis. Two hypotheses about the molecular control mechanism have been proposed-(i) the GATC network regulation is caused by the presence of GATC clusters within the coding sequences; the regulation is the direct consequence of the clusters' hemi-methylation and therefore their elevated melting temperature, (ii) the regulation is caused by the presence of GATCs in the non-coding 500 bp upstream regions of the affected genes; it is the consequence of an interaction with a regulatory protein like Fnr or CAP. An analysis of the transcriptome data has not allowed us to decide between the two hypotheses. We have therefore taken a classic genomic approach, analyzing the statistical distribution of GATC along the chromosome, using a realistic model of the chromosome as theoretical reference. We observe no particular distribution of GATC in the non-coding upstream regions; however, we confirm the presence of GATC clusters within the genes. In order to verify that the particular distribution observed in E. coli is not a statistical artefact, but has a physiological role, we have carried out the same analysis on Salmonella, making the hypothesis that the genes containing a GATC clusters should be largely the same in the two bacteria. This has been indeed observed, showing that the genes containing a GATC cluster are part of a regulation network. The present is a case study, which demonstrates that the analysis of transcriptome data does not always permit to identify the primary cause of a phenomenon observed; on the other hand, a classic genomic approach linked with a comparative study of related genomes may allow this identification.