Recherche avancée
Affichage des résultats 201 à 220 sur 1266 au total
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Some contributions to the estimation of genetic distances between populations
We consider the problem where one wants to evaluate the level of divergence between K populations. Each population is characterized by its allelic frequency prole, where allelic fre- quencies are assumed to be estimated from a sample at several (typically thousands/millions of) markers. In this context the FST is a widely used criterion for the quantication of the divergence between two populations, that can also be adapted to the question of detecting ge- nomic regions that exhibit a divergence level substantially higher than the rest of the genome. Still, the concept of FST remains ambiguous - with dierent available denitions assumed to be "connected" in some sense - and the strategy to estimate the FST when there are more than 2 populations is still an open question, the most popular strategy being to consider all possible pairs of population successively. In this presentation we will rst propose a hierarchical model for the history of population divergence and show that the two classical denitions of the FST (as provided by Hudson and Weir & Cockerham) actually measure independent quantities. We will then provide an estimation procedure based on the moment estimators suggested by Bhatia (in the case of 2 populations) and show how both the FST components and the history of population divergence may be jointly estimated. Lastly, we will consider the problem of detecting genomic regions under selection and provide a segmentation procedure for the identication of such regions. Both the estimation and the segmentation procedures will be illustrated on the 1KG human genome dataset that gathers several human populations sampled over the world.
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Behavioral response games between predator and prey
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The evolution of interdependency between symbiotic organisms by neutral evolution
Symbiosis evolution is often viewed as a progress, with emergence of new adaptive properties. However, symbiosis also enhances the interdependence between partners. I describe several such interdependences, and emphasize that they arise without emergence of new property. Generally, when two partners permanently interact, a mutation in one partner can be complemented by the other. Independency is then lost without any positive selection, in a neutral evolution. The accumulation of such steps makes the reversion to independency unlikely, and drives interdependency in symbiosis.
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Plant Phylogenomics: Elucidating the Evolution of Plant Genes, Gene Families and Genomes
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Prebiotic dynamics of compartmentalized replicators
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Quelle autonomie pour la recherche? Analyses épistémologiques des conditions de la gouvernance des sciences
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From metagenomes to population genomes and back: high-resolution surveys of microorganisms in the surface ocean
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Zebrafish telomerase mutants as a new model for vertebrate ageing
Age is the highest important risk factor for the most prevalent human diseases, including cancer. Telomere shortening is thought to play a central role in the aging process in humans. The link between telomeres and aging is highlighted by the fact that genetic diseases causing telomerase deficiency are associated with premature aging and increased risk of cancer. For the last two decades, this link has been investigated using long telomere mouse models. However, zebrafish has recently emerged as a powerful and complementary model system to study telomere biology. Zebrafish possess human-like telomeres that progressively decline with age. The extensive characterisation of its well-conserved molecular and cellular physiology makes this vertebrate an excellent model to unravel the underlying relationship between telomere shortening, tissue regeneration, aging and disease. In our work, we explore how telomere attrition contributes to cellular senescence, organ dysfunction, aging and disease.
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Evolutionary dynamics of transposable elements in vertebrate genomes
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An evolutionary perspective on meiotic recombination in vertebrates
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Approximations auto-emboîtées des arbres non-ordonnés
Les arbres permettent de modéliser des situations variées en biologie : l'architecture des plantes ou de leur système racinaire, les lignées cellulaires, ou encore la structure secondaire de l'ARN. Savoir traiter des données arborescentes peut donc permettre de résoudre des questions biologiques. Afin de comparer ces données, on peut munir l'espace des arbres d'une métrique, dite distance d'édition. A l'ère des données massives, le problème est alors de calculer en un temps raisonnable la matrice des distances 2 à 2 de la base de données dont on dispose. Je présenterai une stratégie de compression avec perte des arbres qui permet de résoudre au moins partiellement ce problème de complexité temporelle. Nous verrons que cela a des implications sur l'analyse et la modélisation des architectures de certaines plantes.
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May covariation and autocorrelation in demographic rates affect population dynamics in a raptor species
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Science sans conscience n'est que ruine de la nature
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Falling down the Penrose stairs: Natural selection for fewer hotspots sustains their existence
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Genomic research on the Bemisia tabaci species complex: opportunities for collaboration?
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Metabolic responses and generalism in phloem feeders - insights from transcriptomics and metabolomics of Bemisia tabaci
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Adaptation of human populations to changes in diet: human and microbial perspective
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La variation intra et inter-individuelle de la masse et ses conséquences sur la fitness et la dynamique de population
Tous ne sont pas égaux. Les différences phénotypiques entre individus sont à la source de leurs différences de fitness. Chez les ongulés, la masse est un trait déterminant pour la survie et en reproduction. Mon doctorat et mon post-doctorat visaient à approfondir notre compréhension des causes des variations inter et intra-individuelles de la masse et de leurs conséquences sur la fitness et la dynamique de population. Pour ce faire, j'ai été chanceux de pouvoir travailler sur 2 projets à long terme (le mouflon d'Amérique au Canada et le renne au Svalbard) où les individus sont capturés, marqués et suivis tout au long de leur vie. Ceci m'a permis de quantifier l'importance relative de la variation génétique et plastique de la masse sur la dynamique de population. J'explore maintenant d'un point de vue plus mécanistique la variation plastique de la masse. Plus précisément, j'étudie les mécanismes menant aux grandes fluctuations intra-individuelles et interannuelles de la masse causées par l'interaction entre climat et reproduction.
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Est-il légitime de laisser la propriété des données des essais cliniques aux seuls industriels ? les leçons de l'étude 329
Le Pr Healy donnera une conférence sur le travail effectué par son équipe sur les données brutes de l'essai GSK 329 (Paroxétine dans la dépression majeure de l'adolescent) qui ont conduit à une seconde publication (dans le BMJ en 2015) d'un essai paru une première fois dans le JACAP en 2001, avec des conclusions opposées aux conclusions initiales. C'est un exemple rare et instructif d'accès aux données brutes d'un essai clinique et leur analyse par une équipe de chercheurs indépendants. https://www.jaacap.org/article/S0890-8567(09)60309-9/abstract https://www.bmj.com/content/351/bmj.h4320 https://study329.org/ http://www.alison-bass.com/side-effects-3/ « Sexe, antidépresseurs et néolibéralisme » Une seconde intervention, à 14h30 et destinée à un public plus large, traitera de la difficulté de faire reconnaître l'existence d'effets indésirables, en prenant pour exemple les troubles sexuels induits par les ISRS, dont certains semblent être irréversibles. "Le « néomédicalisme » est né à la même époque et est taillé dans la même étoffe que le « néolibéralisme ». Le passage d'un « système de soins » à la « promotion de la santé » a plus contribué à la croissance de l'industrie pharmaceutique qu'il n'a amélioré la santé humaine. De nos jours, la découverte de nombreux cas de problèmes médicaux induits par les médicaments révèle un biais généralisé et un manque patent d'intégrité, tant du côté des industriels que de celui des universitaires. En prenant pour exemple les effets indésirables sexuels médicamenteux, cette conférence illustrera: - ce qui se produit quand un traitement médicamenteux tourne mal - la difficulté à voir ce problème reconnu et l'impossibilité d'obtenir une réparation dans le cadre judiciaire - les étapes que vous et nous pourrions adopter pour changer cette situation - ce qu'il faudrait pour rétablir un véritable soin pour notre santé, et pour notre société plus largement. » As part of the LBBE - UMR5558 seminar (which usually takes place on Thursday), on Tuesday, October 15th, the EMET team will receive Professor David Healy (UK), Amphitheater 4 of the Lyon Est faculty - LAENNEC site, at 1pm. "Is it legitimate to leave the ownership of clinical trial data to industry alone? The lessons of the 329 study" Dr. Healy will give a lecture on the work done by his team on the raw data from the GSK 329 trial (Paroxetine in Adolescent Major Depression) that led to a second publication (in the 2015 BMJ) of an trial first published in the JACAP in 2001, with conclusions opposed to the initial conclusions. This is a rare and informative example of access to raw data from a clinical trial and its analysis by a team of independent researchers. https://www.jaacap.org/article/S0890-8567(09)60309-9/abstract https://www.bmj.com/content/351/bmj.h4320 https://study329.org/ http://www.alison-bass.com/side-effects-3/ "Sex, antidepressants and neoliberalism" A second intervention, at 2:30 pm and intended for a wider audience, will address the difficulty of recognizing the existence of adverse effects, taking as an example the sexual disorders induced by SSRIs antidepressant drugs, some of which appear to be irreversible. "Neomedicalism" was born at the same time and is carved out of the same fabric as "neoliberalism." The shift from a "health care system" to "health promotion" has contributed more to the growth of pharmaceutical industry that it has improved human health. Today, the discovery of many cases of drug-induced medical problems reveals a widespread bias and a patent lack of integrity, both on the part of industry and of academics. As an example of medicated sexual side effects, this lecture will illustrate: - what happens when a drug treatment goes wrong - the difficulty of seeing this problem recognized and the impossibility of obtaining a remedy in the judicial framework - the steps you and we could take to change this situation - what it would take to restore genuine care for our health, and for our society more broadly. " Biography - David Healy David Healy is a Professor of Psychiatry at Bangor University. He studied medicine in University College Dublin, Ireland, and at Cambridge University. He is a former Secretary of the British Association for Psychopharmacology, and author of over 200 peer reviewed articles, 250 other pieces and 24 books, including The Antidepressant Era, and The Creation of Psychopharmacology from Harvard University Press, The Psychopharmacologists Volumes 1-3, Let Them Eat Prozac from New York University Press, Mania from Johns Hopkins University Press and Pharmageddon from California University Press. His areas of research are adverse effects of treatment, clinical trials in psychopharmacology, the history of psychopharmacology, and the impact of both trials and psychotropic drugs on our culture. He has been involved as an expert witness in homicide, suicide and birth defect legal actions involving psychotropic drugs, and in bringing problems with these drugs to the attention of American and British regulators, as well raising awareness of how pharmaceutical companies sell drugs by marketing diseases and co-opting academic opinion-leaders and ghost-writing their articles.
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Prédiction en médecine : exemples d'application des réseaux Bayésiens
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