Un estimateur de distributions ajusté pour une aide à la décision de la neutralité génétique des populations

The estimate of the neutrality of a population is often made from a single measurement based on simulations of random patterns. Disputed cases pose a problem regarding the decision-making about the neutrality of the study population. We propose in this paper to provide assistance to the decision of this problem by coupling a genetically neutral populations simulator to a fast adjusted non-parametric estimator of simulated distributions. The choice of the Epanechnikov kernel for the non-parametric method of estimating the kernel allows an analytical approach of the optimal bandwidth, which leads to an improvement in the complexity and therefore a gain in computing time. The fast and reliable estimation of simulated distributions allows to assess the credibility of the decisions about the neutrality of these populations. These results are illustrated by two Tunisian populations whose neutrality is not genetically determined.     

De la géographie sociale en archéologie paléolithique : concepts et apports du Magdalénien des Pyrénées

Landscape archaeologies that pay attention to cultural importance of place have become increasingly common in recent years in many parts of the world. However, these approaches have largely failed to make inroads into Pleistocene European hunter-gatherer archaeology. This is partly due to a focus on economics, survival, and neo-liberal assumptions of “efficiency” in early modern human behavior. With evidence of lithic use drawn from cave sites, survey, and open-air excavation, I argue that Upper Paleolithic hunter-gatherers left clues to the importance of certain places in the landscape. Lithic tools in particular have been undervalued for their symbolic meaning, which goes well beyond style and ethnicity models. Raw material has been seen as evidence of mobility and trade, but possible cultural motives behind material choices have been downplayed or ignored.     

Mise en évidence d'un mécanisme génétique contrôlant la synthèse de certaines sous-classes des γG dans des hypogammaglobulinemies dites acquises

Résumé L'étude de différents allotypes du système Gm a été pratiquée sur les sérums provenant de onze familles dont au moins un des membres présentait un déficit mineur ou grave portant sur une ou plusieurs classes d'immunoglobulines.Dans six de ces familles, deux ordres de faits sont observés, simultanément ou non, chez des sujets ne présentant, par les méthodes classiques, aucun désordre immunologique:une diminution de l'expression phénotypique d'un ou plusieurs facteurs qui permet de conclure à un déficit sélectif de certaines sous-classes de G; ces déficits sont, parfois, transmis directement à la génération suivante;des anomalies d'ordre qualitatif se caractérisant par la présence de phénotypes, en règle générale, rarement rencontrés parmi des Caucasiens.L'hypothèse faisant appel à l'existence de gènes de structure rares ou anormaux pour expliquer ces faits ne peut être retenue car elle aboutit à la constatation de trop nombreuses exclusions de paternité ou de maternité.Dans une seconde hypothèse, nous supposons qu'existent des gènes de régulation responsables de la synthèse des chaines ₁, ₂ et ₃ et que les anomalies phénotypiques observées sont l'expression de la modification de ces gènes.La transmission de ces gènes de régulation se ferait indépendamment de celle des gènes de structure.

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Demonstration of a genetic mechanism controlling the synthesis of certain G subclasses in socalled acquired hypogammaglobulinemias

Summary Different allotypes of the Gm system were studied on sera from eleven families where at least one of the members had a minor or important deficiency in one or several classes of immunoglobulins.In six of these families two facts were observed, simultaneously or not, in subjects showing no immunologic disorder, as revealed by conventional methods:a reduction in the phenotypic expression of one or several factors which allowed to conclude that there is a selective deficiency in certain G subclasses; these deficiencies are sometimes directly transmitted to the following generation;qualitative anomalies characterized by the presence of phenotypes, as a general rule, rarely encountered among Caucasians.The hypothesis based on the existence of rare or abnormal structural genes could not be applied to explain these facts because it would have led to the statement that there are too many exclusions of paternity or maternity.In a second hypothesis, we supposed that there exist regulator genes, responsible for the synthesis of the 1, 2, and 3 chains, and that the observed phenotypic anomalies are an expression of the mutation of these genes.The transmission of these regulator genes could be independent of that of the structural genes.

     

Provenance d’artefacts en rhyolite corse : évaluation des méthodes d’analyse géochimique

Through the analysis of flint and obsidian artefacts, numerous studies have shown the links that existed between Corsica and Sardinia during Neolithic and Chalcolithic. However, we have almost no information about the movements and exchanges that took place in Corsica itself. Rhyolite, a siliceous volcanic rock, has been exploited in Corsica and disseminated throughout the territory from the early Neolithic. Up to now, only one major study has been conducted in the North of the island, in order to identify, by petrographic analysis, the raw material deposits of these rhyolite artefacts. Petrography is a destructive method; it is thus difficult to apply it to large series of archaeological objects. Our aim was therefore to investigate less invasive analytical methods, based on the geochemistry of rocks, in order to conduct future studies based on these rhyolite remains. We analysed 34 geological samples from four different sources, as well as 31 archaeological samples unearthed at three different archaeological areas. We show that EDXRF is an effective method to discriminate sources but also to characterise artefacts using nondestructive protocol. LA-ICP-MS encounters issues due to heterogeneity of the studied rocks. However, we show that by adjusting our testing protocol this method can complement the EDXRF analysis, which is ineffective on objects that are too thin.