Showing results 1741 to 1760 on 1826 in total
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Cumulative culture requires individuals to build upon the knowledge of previous generations such that trait complexity/efficiency evolves across generations. Such cumulative cultural evolution is arguably unique to humans and is widely held to be responsible for our outstanding success in colonising virtually every terrestrial habitat on the planet and solving countless ecological, social and technological challenges. In contrast, social learning (learning from others) underlies the wide-spread occurrence of traditions or culture in all animals. Although social learning is a cheap and efficient form of learning, it is not adaptive to use social information indiscriminately due to its potential unreliability. Thus it is predicted that social learning strategies (heuristics / transmission biases) should evolve enabling individuals to avoid the costs associated with asocial learning and determine when they should use social information and from whom they should acquire it. I shall review several of my recent empirical studies, with young children and non-human primates, highlighting the role of socio-cognition, and in particular the potential role of transmission biases, in humanity's striking capacity for cumulative culture. (page web: https://www.dur.ac.uk/research/directory/staff/?id=5444)
Thèse de Sébastien Lambert le vendredi 29 novembre 2019 à 13 h 30, BU salle de conférence (La Doua)
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Des chercheuses et chercheurs du LBBE ont suivit avec Claire Truche, metteuse en scène, les premiers pas de cette aventure théâtrale qui donnera lieu à trois représentations au théâtre Astrée cette fin de semaine.
Lisa Nicvert and Lucie Thel, doctoral students at the LBBE, participate in the 3rd edition of the "embarked conferences", on the lake of the Parc de la Tête d'Or.
Mitochondrial genomes (mtDNA) are normally maternally inherited and encode for subunits of respiratory chain complexes and ATP synthase among others. The integrity of mtDNA is crucial for cellular energetic and redox homeostasis, and mtDNA mutations are associated with modifications of individual fitness and longevity. Bivalves are the only zoological group in which Doubly Uniparental Inheritance (DUI), characterized by the presence of two divergent mitochondrial genomes within different tissues of male individuals, is frequently observed. The F-genome, maternally inherited, is found in somatic tissue and female gonads whereas the M-mtDNA is found in male gonadic tissue only. The clam Arctica islandica is widely distributed throughout the North Atlantic shelf regions. Due to different environmental regimes (salinity, temperature, oxygen), the maximum lifespan of its populations varies between >500 years around Iceland and 35 years in the Baltic Sea. I will present our recent investigations that describe for the first time the existence of the DUI system in Arctica islandica. Based on 16S and cytochrome b markers, we highlight the presence of an M-genome in male gonads in individuals belonging to Baltic and North Sea populations. The two genomes show a low level of sequence divergence compared to other DUI species, around 6-8% at the nucleotide level. Whilst the analysis of mitochondrial markers generally indicated genetically homogeneity of all North Atlantic populations, they further reveal few clam individuals that carry a "divergent" mtDNA haplotype, resembling the M-genome. These individuals occurred however exclusively in the Icelandic population. Unlike the M-genome, which is confined to male gonadic tissue in DUI species, this "divergent" mtDNA occurs in somatic tissues from 20% of individuals of both sexes. In association with transcriptomic and biochemical data, we will discuss the possible impacts of this uncommon mitochondrial genome on Arctica islandica biology and cellular physiology. This study will enhance the understanding of the role of DUI and mtDNA in general for fitness, aging and adaptation of bivalves.
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Le jeudi 13 Janvier à 20h30, Sylvain Charlat, chercheur au LBBE, participera à un débat à l'issue de la projection du film "Les Fils de l'homme", à l'aquarium ciné-café.
Biological networks of large dimensions, with their diagram of interactions, are often well represented by a Boolean model with a family of logical rules. An advantage of Boolean and discrete modelling is the possibility of fully characterizing all qualitative dynamical trajectories of a particular network, based simply on the structure of links and interactions between nodes. A biological network may have different qualitative behaviours in response to different conditions. For instance, in response to different inputs, the system may have a single steady state, or multiple steady states, or exhibit oscillatory behaviour. In this context, using the asynchronous transition graph of the Boolean network, we have developed a method for identifying the groups of active or operational interactions that are responsible for a given dynamic behaviour.As an example, a model of an apoptosis network will be analysed. Two core groups of elements and interactions are identified: they correspond to two different mechanisms that may be used by the cell for the decision between apoptosis or cell survival.