218 research outputs found

    Identité biologique des artisans moustériens de Kebara (Mont Carmel, Israël) Réflexions sur le concept de néanderthalien au Levant méditerranéen

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    DĂšs les premiĂšres dĂ©couvertes de fossiles humains provenant du Bassin MĂ©diterranĂ©en oriental et datĂ©s du PlĂ©istocĂšne supĂ©rieur, il est apparu Ă©vident que la documentation anthropologique illustrait une hĂ©tĂ©rogĂ©nĂ©itĂ© biologique, suscitant des interprĂ©tations diffĂ©rentes. Par la suite, l’enrichissement de la documentation avec de nouvelles fouilles est venu alimenter, au sein de la communautĂ© scientifique, les discussions portant aussi bien sur les affinitĂ©s phylogĂ©nĂ©tiques des fossiles que sur leur position chronologique. La prise en compte, sur ces fossiles proche-orientaux, de l’originalitĂ© de l’assemblage de caractĂšres anatomiques prĂ©sents ne doit pas ĂȘtre sous-estimĂ©e pour une meilleure Ă©valuation des composantes rĂ©gionales. C’est ce qui est proposĂ© Ă  propos de Kebara, l’objectif Ă©tant de favoriser une approche cohĂ©rente de la diversitĂ© biologique des hommes du PalĂ©olithique moyen dans la rĂ©gion, qui n’exclut pas les influences extra-europĂ©ennes.The southern Mediterranean Levant has attracted the attention of the scientific community since the early excavations conducted at the beginning of the 20th century on several sites, which provided a significant sample of Upper Pleistocene hominids. Additional skeletal material, circumscribed geographically and chronologically, raises several questions concerning the biological differences and similarities between the hominid samples represented, and their geographical position at the crossroads of Africa and Eurasia. The excellent state of preservation of the hominid remains enables a new insight into the anatomy of Levantine Middle Palaeolithic populations and provides important data for reconstructing the pattern of human evolution in the Near East. With this in view, re-examination of some skeletal remains recovered at Kebara Cave suggests. that biological differences and similarities may have existed between Neanderthals and Levantine Middle Palaeolithic hominids, strengthening the existence of regional variation

    ĐžŃ†Ń–ĐœĐșĐ° яĐșĐŸŃŃ‚Ń– Đ¶ĐžŃ‚Ń‚Ń у ĐČіĐșĐŸĐČох ĐżĐ”Ń€ŃˆĐŸĐČĐ°ĐłŃ–Ń‚ĐœĐžŃ… та ĐČĐ°ĐłŃ–Ń‚ĐœĐžŃ… Đ· ĐČДлОĐșĐžĐŒ Ń–ĐœŃ‚Đ”Ń€ĐłĐ”ĐœĐ”Ń‚ĐžŃ‡ĐœĐžĐŒ Ń–ĐœŃ‚Đ”Ń€ĐČĐ°Đ»ĐŸĐŒ

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    ĐŸŃ€ĐŸĐČĐ”ĐŽĐ”ĐœĐŸ ĐžĐ·ŃƒŃ‡Đ”ĐœĐžĐ” ĐżĐŸĐșазатДлДĐč ĐșачДстĐČĐ° Đ¶ĐžĐ·ĐœĐž у 120 ĐČĐŸĐ·Ń€Đ°ŃŃ‚ĐœŃ‹Ń… пДрĐČĐŸĐ±Đ”Ń€Đ”ĐŒĐ”ĐœĐœŃ‹Ń… Đž 240 Đ±Đ”Ń€Đ”ĐŒĐ”ĐœĐœŃ‹Ń… с Đ±ĐŸĐ»ŃŒŃˆĐžĐŒ ĐžĐœŃ‚Đ”Ń€ĐłĐ”ĐœĐ”Ń‚ĐžŃ‡Đ”ŃĐșĐžĐŒ ĐžĐœŃ‚Đ”Ń€ĐČĐ°Đ»ĐŸĐŒ с ĐžŃĐżĐŸĐ»ŃŒĐ·ĐŸĐČĐ°ĐœĐžĐ”ĐŒ ĐŸĐżŃ€ĐŸŃĐœĐžĐșĐ° SF-36 Health Status Survey, Ń€Đ°Đ·Ń€Đ°Đ±ĐŸŃ‚Đ°ĐœĐœĐŸĐłĐŸ The Health Institute, New England Medical Center, Boston, USA. Đ˜ŃŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐžĐ” ĐżĐŸĐșĐ°Đ·Đ°Đ»ĐŸ, Ń‡Ń‚ĐŸ ĐżĐ°Ń†ĐžĐ”ĐœŃ‚ĐșĐž ĐŸĐ±Đ”ĐžŃ… групп ĐžĐŒĐ”ŃŽŃ‚ ĐœĐžĐ·ĐșОД ĐżĐŸĐșазатДлО ĐșачДстĐČĐ° Đ¶ĐžĐ·ĐœĐž. Про сраĐČĐœĐ”ĐœĐžĐž Đ±ĐŸĐ»ŃŒŃˆĐžĐœŃŃ‚ĐČĐŸ ĐžĐ·ŃƒŃ‡Đ°Đ”ĐŒŃ‹Ń… ĐżĐ°Ń€Đ°ĐŒĐ”Ń‚Ń€ĐŸĐČ ĐŸŃ†Đ”ĐœĐșĐž ĐșачДстĐČĐ° Đ¶ĐžĐ·ĐœĐž ĐČ ĐŸĐ±ŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐœŃ‹Ń… группах ĐœĐ” ĐŸŃ‚Đ»ĐžŃ‡Đ°Đ»ĐžŃŃŒ, ĐŸĐŽĐœĐ°ĐșĐŸ у ĐżĐ°Ń†ĐžĐ”ĐœŃ‚ĐŸĐș с Đ±ĐŸĐ»ŃŒŃˆĐžĐŒ ĐžĐœŃ‚Đ”Ń€ĐłĐ”ĐœĐ”Ń‚ĐžŃ‡Đ”ŃĐșĐžĐŒ ĐžĐœŃ‚Đ”Ń€ĐČĐ°Đ»ĐŸĐŒ – ĐŽĐŸŃŃ‚ĐŸĐČĐ”Ń€ĐœĐŸ ĐČŃ‹ŃˆĐ” ĐŸŃ†Đ”ĐœĐșĐ° ŃĐŸŃ†ĐžĐ°Đ»ŃŒĐœĐŸĐč Ń€ĐŸĐ»Đž Đž ŃĐœĐ”Ń€ĐłĐ”Ń‚ĐžŃ‡ĐœĐŸŃŃ‚Đž. ĐžŃ†Đ”ĐœĐșĐ° ĐșачДстĐČĐ° Đ¶ĐžĐ·ĐœĐž у ĐČĐŸĐ·Ń€Đ°ŃŃ‚ĐœŃ‹Ń… пДрĐČĐŸĐ±Đ”Ń€Đ”ĐŒĐ”ĐœĐœŃ‹Ń… Đž Đ±Đ”Ń€Đ”ĐŒĐ”ĐœĐœŃ‹Ń… с Đ±ĐŸĐ»ŃŒŃˆĐžĐŒ ĐžĐœŃ‚Đ”Ń€ĐłĐ”ĐœĐ”Ń‚ĐžŃ‡Đ”ŃĐșĐžĐŒ ĐžĐœŃ‚Đ”Ń€ĐČĐ°Đ»ĐŸĐŒ яĐČĐ»ŃĐ”Ń‚ŃŃ ĐČĐ°Đ¶ĐœŃ‹ĐŒ ŃĐ”ĐłĐŒĐ”ĐœŃ‚ĐŸĐŒ ĐœĐ°Đ±Đ»ŃŽĐŽĐ”ĐœĐžŃ ĐČĐŸ ĐČŃ€Đ”ĐŒŃ Đ±Đ”Ń€Đ”ĐŒĐ”ĐœĐœĐŸŃŃ‚Đž, ĐșĐŸŃ‚ĐŸŃ€Ń‹Đč ĐŸŃ†Đ”ĐœĐžĐČаДт пДрспДĐșтоĐČы разĐČотоя Đ±Đ”Ń€Đ”ĐŒĐ”ĐœĐœĐŸŃŃ‚Đž ĐČ ĐżŃĐžŃ…ĐŸĐ»ĐŸĐłĐžŃ‡Đ”ŃĐșĐŸĐŒ, фОзОчДсĐșĐŸĐŒ Đž ŃĐŸŃ†ĐžĐ°Đ»ŃŒĐœĐŸĐŒ аспДĐșтах.A study of the life quality of 120 over-age primigravidas and of 240 women with a large intergenetic interval has been carried out using the questionnaire SF-36 Health Status Survey developed by The Health Institute, New England Medical Center, Boston, USA. This research has shown that the patients in the both groups have a low quality of life. The major part of the life quality parameters were the same in the both groups, however, in patients with a large interval between births the values of the social role and the energy level were significantly higher. The life quality of over-age primigravidas and pregnant women with a large interval between successive births is an important sector of observation during pregnancy, which allows assessing the prospects of pregnancy in the psychological, physical, and social aspects

    Molecular Phylogenetic Evaluation of Classification and Scenarios of Character Evolution in Calcareous Sponges (Porifera, Class Calcarea)

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    Calcareous sponges (Phylum Porifera, Class Calcarea) are known to be taxonomically difficult. Previous molecular studies have revealed many discrepancies between classically recognized taxa and the observed relationships at the order, family and genus levels; these inconsistencies question underlying hypotheses regarding the evolution of certain morphological characters. Therefore, we extended the available taxa and character set by sequencing the complete small subunit (SSU) rDNA and the almost complete large subunit (LSU) rDNA of additional key species and complemented this dataset by substantially increasing the length of available LSU sequences. Phylogenetic analyses provided new hypotheses about the relationships of Calcarea and about the evolution of certain morphological characters. We tested our phylogeny against competing phylogenetic hypotheses presented by previous classification systems. Our data reject the current order-level classification by again finding non-monophyletic Leucosolenida, Clathrinida and Murrayonida. In the subclass Calcinea, we recovered a clade that includes all species with a cortex, which is largely consistent with the previously proposed order Leucettida. Other orders that had been rejected in the current system were not found, but could not be rejected in our tests either. We found several additional families and genera polyphyletic: the families Leucascidae and Leucaltidae and the genus Leucetta in Calcinea, and in Calcaronea the family Amphoriscidae and the genus Ute. Our phylogeny also provided support for the vaguely suspected close relationship of several members of Grantiidae with giantortical diactines to members of Heteropiidae. Similarly, our analyses revealed several unexpected affinities, such as a sister group relationship between Leucettusa (Leucaltidae) and Leucettidae and between Leucascandra (Jenkinidae) and Sycon carteri (Sycettidae). According to our results, the taxonomy of Calcarea is in desperate need of a thorough revision, which cannot be achieved by considering morphology alone or relying on a taxon sampling based on the current classification below the subclass level

    New Implications on Genomic Adaptation Derived from the Helicobacter pylori Genome Comparison

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    BACKGROUND: Helicobacter pylori has a reduced genome and lives in a tough environment for long-term persistence. It evolved with its particular characteristics for biological adaptation. Because several H. pylori genome sequences are available, comparative analysis could help to better understand genomic adaptation of this particular bacterium. PRINCIPAL FINDINGS: We analyzed nine H. pylori genomes with emphasis on microevolution from a different perspective. Inversion was an important factor to shape the genome structure. Illegitimate recombination not only led to genomic inversion but also inverted fragment duplication, both of which contributed to the creation of new genes and gene family, and further, homological recombination contributed to events of inversion. Based on the information of genomic rearrangement, the first genome scaffold structure of H. pylori last common ancestor was produced. The core genome consists of 1186 genes, of which 22 genes could particularly adapt to human stomach niche. H. pylori contains high proportion of pseudogenes whose genesis was principally caused by homopolynucleotide (HPN) mutations. Such mutations are reversible and facilitate the control of gene expression through the change of DNA structure. The reversible mutations and a quasi-panmictic feature could allow such genes or gene fragments frequently transferred within or between populations. Hence, pseudogenes could be a reservoir of adaptation materials and the HPN mutations could be favorable to H. pylori adaptation, leading to HPN accumulation on the genomes, which corresponds to a special feature of Helicobacter species: extremely high HPN composition of genome. CONCLUSION: Our research demonstrated that both genome content and structure of H. pylori have been highly adapted to its particular life style

    MSH3 polymorphisms and protein levels affect CAG repeat instability in huntington's disease mice

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    Expansions of trinucleotide CAG/CTG repeats in somatic tissues are thought to contribute to ongoing disease progression through an affected individual's life with Huntington's disease or myotonic dystrophy. Broad ranges of repeat instability arise between individuals with expanded repeats, suggesting the existence of modifiers of repeat instability. Mice with expanded CAG/CTG repeats show variable levels of instability depending upon mouse strain. However, to date the genetic modifiers underlying these differences have not been identified. We show that in liver and striatum the R6/1 Huntington's disease (HD) (CAG)~100 transgene, when present in a congenic C57BL/6J (B6) background, incurred expansion-biased repeat mutations, whereas the repeat was stable in a congenic BALB/cByJ (CBy) background. Reciprocal congenic mice revealed the Msh3 gene as the determinant for the differences in repeat instability. Expansion bias was observed in congenic mice homozygous for the B6 Msh3 gene on a CBy background, while the CAG tract was stabilized in congenics homozygous for the CBy Msh3 gene on a B6 background. The CAG stabilization was as dramatic as genetic deficiency of Msh2. The B6 and CBy Msh3 genes had identical promoters but differed in coding regions and showed strikingly different protein levels. B6 MSH3 variant protein is highly expressed and associated with CAG expansions, while the CBy MSH3 variant protein is expressed at barely detectable levels, associating with CAG stability. The DHFR protein, which is divergently transcribed from a promoter shared by the Msh3 gene, did not show varied levels between mouse strains. Thus, naturally occurring MSH3 protein polymorphisms are modifiers of CAG repeat instability, likely through variable MSH3 protein stability. Since evidence supports that somatic CAG instability is a modifier and predictor of disease, our data are consistent with the hypothesis that variable levels of CAG instability associated with polymorphisms of DNA repair genes may have prognostic implications for various repeat-associated diseases

    Potential pitfalls of modelling ribosomal RNA data in phylogenetic tree reconstruction: Evidence from case studies in the Metazoa

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    <p>Abstract</p> <p>Background</p> <p>Failure to account for covariation patterns in helical regions of ribosomal RNA (rRNA) genes has the potential to misdirect the estimation of the phylogenetic signal of the data. Furthermore, the extremes of length variation among taxa, combined with regional substitution rate variation can mislead the alignment of rRNA sequences and thus distort subsequent tree reconstructions. However, recent developments in phylogenetic methodology now allow a comprehensive integration of secondary structures in alignment and tree reconstruction analyses based on rRNA sequences, which has been shown to correct some of these problems. Here, we explore the potentials of RNA substitution models and the interactions of specific model setups with the inherent pattern of covariation in rRNA stems and substitution rate variation among loop regions.</p> <p>Results</p> <p>We found an explicit impact of RNA substitution models on tree reconstruction analyses. The application of specific RNA models in tree reconstructions is hampered by interaction between the appropriate modelling of covarying sites in stem regions, and excessive homoplasy in some loop regions. RNA models often failed to recover reasonable trees when single-stranded regions are excessively homoplastic, because these regions contribute a greater proportion of the data when covarying sites are essentially downweighted. In this context, the RNA6A model outperformed all other models, including the more parametrized RNA7 and RNA16 models.</p> <p>Conclusions</p> <p>Our results depict a trade-off between increased accuracy in estimation of interdependencies in helical regions with the risk of magnifying positions lacking phylogenetic signal. We can therefore conclude that caution is warranted when applying rRNA covariation models, and suggest that loop regions be independently screened for phylogenetic signal, and eliminated when they are indistinguishable from random noise. In addition to covariation and homoplasy, other factors, like non-stationarity of substitution rates and base compositional heterogeneity, can disrupt the signal of ribosomal RNA data. All these factors dictate sophisticated estimation of evolutionary pattern in rRNA data, just as other molecular data require similarly complicated (but different) corrections.</p
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