The application of dental wear study to murids has always been ruled out because of their omnivorous diet, which does not leave significant wear on the dentition. Nevertheless, in our work we select ...Apodemus sylvaticus (wood mouse) as the object of study for several reasons: its seasonal diet, its ability to resist the gastric juices of predators, the fact that it has not undergone major morphological changes since its appearance 3 million years ago, and its widespread distribution throughout much of Europe and part of Africa. The importance of this work lies in the modifications we make to the dental wear methodology for its application to murids. These enable us to obtain quantitative data on the entire tooth surface. The sample chosen was a total of 75 lower first molars from two different archaeological sites: Teixoneres cave and Xaragalls cave. The chronology of the samples chosen ranges from Marine Isotope Stages 5-3. The data obtained reveal that the part of the tooth that shows most wear is the distal part (entoconid). Furthermore, the results provide us with relevant information on the types of accumulations of remains in the caves (short vs. long term), as well as on the seasonality of Neanderthal occupations during the Upper Pleistocene (MIS5-3) of the northeastern Iberian Peninsula.
Changes in gene regulatory elements play critical roles in human phenotypic divergence. However, identifying the base-pair changes responsible for the distinctive morphology of Homo sapiens remains ...challenging. Here, we report a noncoding single-nucleotide polymorphism (SNP), rs41298798, as a potential causal variant contributing to the morphology of the skull base and vertebral structures found in Homo sapiens. Screening for differentially regulated genes between Homo sapiens and extinct relatives revealed 13 candidate genes associated with basicranial development, with TBX1, implicated in DiGeorge syndrome, playing a pivotal role. Epigenetic markers and in silico analyses prioritized rs41298798 within a TBX1 intron for functional validation. CRISPR editing revealed that the 41-base-pair region surrounding rs41298798 modulates gene expression at 22q11.21. The derived allele of rs41298798 acts as an allele-specific enhancer mediated by E2F1, resulting in increased TBX1 expression levels compared to the ancestral allele. Tbx1-knockout mice exhibited skull base and vertebral abnormalities similar to those seen in DiGeorge syndrome. Phenotypic differences associated with TBX1 deficiency are observed between Homo sapiens and Neanderthals (Homo neanderthalensis). In conclusion, the regulatory divergence of TBX1 contributes to the formation of skull base and vertebral structures found in Homo sapiens.
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Changes in gene regulatory elements are crucial for human phenotypic divergence. However, identifying the changes responsible for the distinct morphology of Homo sapiens remains challenging. Here, we report a noncoding SNP, rs41298798, in TBX1 as a potential causal variant contributing to the basicranial morphology found in Homo sapiens.
The size and shape of the Neandertal thorax has been debated since the first discovery of Neandertal ribs more than 150 years ago, with workers proposing different interpretations ranging from a ...Neandertal thoracic morphology that is indistinguishable from modern humans, to one that was significantly different from them. Here, we provide a virtual 3D reconstruction of the thorax of the adult male Kebara 2 Neandertal. Our analyses reveal that the Kebara 2 thorax is significantly different but not larger from that of modern humans, wider in its lower segment, which parallels his wide bi-iliac breadth, and with a more invaginated vertebral column. Kinematic analyses show that rib cages that are wider in their lower segment produce greater overall size increments (respiratory capacity) during inspiration. We hypothesize that Neandertals may have had a subtle, but somewhat different breathing mechanism compared to modern humans.
We have identified a fixed nonsynonymous sequence difference between humans (Val381; derived variant) and Neandertals (Ala381; ancestral variant) in the ligand-binding domain of the aryl hydrocarbon ...receptor (AHR) gene. In an exome sequence analysis of four Neandertal and Denisovan individuals compared with nine modern humans, there are only 90 total nucleotide sites genome-wide for which archaic hominins are fixed for the ancestral nonsynonymous variant and the modern humans are fixed for the derived variant. Of those sites, only 27, including Val381 in the AHR, also have no reported variability in the human dbSNP database, further suggesting that this highly conserved functional variant is a rare event. Functional analysis of the amino acid variant Ala381 within the AHR carried by Neandertals and nonhuman primates indicate enhanced polycyclic aromatic hydrocarbon (PAH) binding, DNA binding capacity, and AHR mediated transcriptional activity compared with the human AHR. Also relative to human AHR, the Neandertal AHR exhibited 150-1000 times greater sensitivity to induction of Cyp1a1 and Cyp1b1 expression by PAHs (e.g., benzo(a)pyrene). The resulting CYP1A1/CYP1B1 enzymes are responsible for PAH first pass metabolism, which can result in the generation of toxic intermediates and perhaps AHR-associated toxicities. In contrast, the human AHR retains the ancestral sensitivity observed in primates to nontoxic endogenous AHR ligands (e.g., indole, indoxyl sulfate). Our findings reveal that a functionally significant change in the AHR occurred uniquely in humans, relative to other primates, that would attenuate the response to many environmental pollutants, including chemicals present in smoke from fire use during cooking.
Humans coexisted and interbred with other hominins which later became extinct. These archaic hominins are known to us only through fossil records and for two cases, genome sequences. Here, we ...engineer Neanderthal and Denisovan sequences into thousands of artificial genes to reconstruct the pre-mRNA processing patterns of these extinct populations. Of the 5,169 alleles tested in this massively parallel splicing reporter assay (MaPSy), we report 962 exonic splicing mutations that correspond to differences in exon recognition between extant and extinct hominins. Using MaPSy splicing variants, predicted splicing variants, and splicing quantitative trait loci, we show that splice-disrupting variants experienced greater purifying selection in anatomically modern humans than that in Neanderthals. Adaptively introgressed variants were enriched for moderate-effect splicing variants, consistent with positive selection for alternative spliced alleles following introgression. As particularly compelling examples, we characterized a unique tissue-specific alternative splicing variant at the adaptively introgressed innate immunity gene
, as well as a unique Neanderthal introgressed alternative splicing variant in the gene
that encodes perlecan. We further identified potentially pathogenic splicing variants found only in Neanderthals and Denisovans in genes related to sperm maturation and immunity. Finally, we found splicing variants that may contribute to variation among modern humans in total bilirubin, balding, hemoglobin levels, and lung capacity. Our findings provide unique insights into natural selection acting on splicing in human evolution and demonstrate how functional assays can be used to identify candidate causal variants underlying differences in gene regulation and phenotype.
Europe is characterized by an uneven record of Middle Paleolithic occupations. Specifically, large parts of southeastern Europe display markedly lower site densities and less intensive evidence of ...human presence than is found elsewhere; this has often resulted in the exclusion of the Balkans from debates related to Pleistocene human adaptation. The discrepancy stems either from the lower population densities of southeastern Europe or an imbalance in research across Europe. Additionally, our understanding of Balkan Middle Paleolithic stone tool industries suffers from the use of Mousterian labels defined when Bordian typology was the chief method of lithic analysis. Industrial facies then defined and still in use include Balkan Charentian, Levallois Mousterian, Micromousterian, Denticulate Mousterian; their relation with the rest of the Eurasian record was and remains unclear. This paper sets aside the issue of scarcity of Pleistocene occupations and tries to address Neanderthal biogeography, and variations in Neanderthal technological behavior and subsistence, based on the available record. It reviews the current Middle Paleolithic record in the Balkans, presents the apparent temporal and spatial trends, and presents the provisional biogeography of hominins, including scenarios for the demise of Neanderthals at or soon after the arrival of modern humans in Europe. The paper ends with a discussion of perspectives for future research arising from this analysis of the available record and proposes some hypotheses regarding the role of the Balkans in the overall context of the occupational history of western Eurasia in the Middle/Late Pleistocene.
•This study investigates the mobile toolkit of Neanderthals.•The analysis is performed on lithic assemblages of unit III of Teixoneres Cave.•The results reveal that bulk of the toolkit is composed of ...knapping by-products.•At Teixoneres Cave, Neanderthals were equipped with generalized set of tools.
Hunter–gatherers have a nomadic lifestyle and move frequently on the landscape based on the seasonal distribution of resources. During these displacements, carrying capacities are limited, and the composition of the transported gear is generally planned ahead of the activity to perform. During the Pleistocene, prehistoric hunter–gatherers faced similar difficulties in exploiting the territory and employed different strategies for coping with their subsistence needs and the possible shortage of stone tools. The understanding of how these behaviors developed diachronically is pivotal for the reconstruction of the human trajectories of land use in different environments, orographic settings, and climates. Thus far, the identification of the mobile toolkit has been related to blanks produced with allochthonous rocks, whereas the recognition of the transported artefacts knapped in local and semi-local raw materials encounters more difficulties because of the possible association with the lithic production conducted at the site. In this paper, we present the mobile toolkit of sub-unit IIIb and IIIa of Teixoneres Cave, a Middle Paleolithic site where a clear differentiation between in-situ knapping activities in local quartz and the import of stone tools in other raw materials is documented. The analysis of these latter assemblages reveals that the bulk of the toolkit is composed of knapping by-products and that the number of curated artefacts, Levallois flakes, and cores is significantly lower. Results show that the main strategy of transport at Teixoneres Cave was a combination of hunting and cutting tools aiming toward a generalized set of gears instead of narrowing the equipment to few specialized items. These new data highlight the plasticity of Neanderthals’ technological organization in the western Mediterranean.
The transition from the Middle Paleolithic (MP) to Upper Paleolithic (UP) is marked by the replacement of late Neandertals by modern humans in Europe between 50,000 and 40,000 y ago. Châtelperronian ...(CP) artifact assemblages found in central France and northern Spain date to this time period. So far, it is the only such assemblage type that has yielded Neandertal remains directly associated with UP style artifacts. CP assemblages also include body ornaments, otherwise virtually unknown in the Neandertal world. However, it has been argued that instead of the CP being manufactured by Neandertals, site formation processes and layer admixture resulted in the chance association of Neanderthal remains, CP assemblages, and body ornaments. Here, we report a series of accelerator mass spectrometry radiocarbon dates on ultrafiltered bone collagen extracted from 40 well-preserved bone fragments from the late Mousterian, CP, and Protoaurignacian layers at the Grotte du Renne site (at Arcy-sur-Cure, France). Our radiocarbon results are inconsistent with the admixture hypothesis. Further, we report a direct date on the Neandertal CP skeleton from Saint-Césaire (France). This date corroborates the assignment of CP assemblages to the latest Neandertals of western Europe. Importantly, our results establish that the production of body ornaments in the CP postdates the arrival of modern humans in neighboring regions of Europe. This new behavior could therefore have been the result of cultural diffusion from modern to Neandertal groups.
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