L'équipe EPCC a reçu un financement de l'Europe pour son projet dont Frédéric Méry est le coordinateur.
Pour lire le résumé du projet en anglais, cliquer ici.
Memory (i.e. the ability to store and retrieve information) plays a crucial role in the development of an animal’s behaviour within its lifespan and is often important for its survival and reproductive success. Memory is itself a product of evolution and the degree to which information is maintained in the brain varies among species and among different types of behaviour. Findings from vertebrate behavioural pharmacology have challenged the traditional view of memory formation as a direct flow from short-term to long-term storage. Evidence points instead to an intricate, multiphase pathway of memory consolidation. Different components of memory emerge at different times after the event to be memorized has taken place. In addition, their duration and times of onset can vary with different tasks and species.
For most of the 20th century, memory has not figured in "mainstream" evolutionary research. However, for an evolutionary biologist these findings raise the question of the functional and evolutionary relationships among, as well as the genetic basis of, these different components of memory.
The central part of the project is the study of the sources of memory variation. Using Drosophila as a model system, we investigate how genetic variation, environmental and developmental factors may affect specifically some memory phases and how these variations may depend on the type of cognitive task performed by the individual. As an example, we found that flies artificially selected for improvement of a specific consolidated memory phase showed a decrease of other memory phases suggesting a potential evolutionary trade off between the different memory components. Such genetic trade-off may impact on the evolution of cognitive capacities. Environmental factors are also well known to affect phenotypic traits. We investigate the effect of social interaction on individual memory capacities and found that some memory phases were particularly sensitive to the social environment and this environmental effect was dependent on a mutation at the foraging locus. Finally, variation in learning and memory are likely to depend on developmental factors. In human, children born to older parents tend to have lower intelligence and are at higher risk for disorders such as schizophrenia and autism. Such observations of ageing damage being passed on from parents to offspring are not often considered within the evolutionary theory of ageing and explanatory factors are difficult to isolate especially in human. In Drosophila, we observed a 25% decrease of a specific memory phase due solely to the age of the parents. We are at present trying to understand the genetic and neural bases of this parental age effect.
To extend these results and understand how the dynamic of the different memory phases may be sensitive to the type of cognitive task performed, we are currently developing new learning protocols involving other sensory and neuronal pathways. As an example, we developed a social learning protocol in which flies have to use public information to choose a suitable oviposition site. This type of experiment opens new perspectives on the study of the genetic and neural bases of social learning.
Taken altogether these results suggest a strong interplay of factors to mold the development and plasticity of the different memory phases. The study of this interplay is fundamental for a better understanding of the evolution of animal cognition.
Bourse de retour Marie Curie
Une bourse de retour Marie Curie a été attribuée à Arnaud Le Rouzic dans l'équipe ELEGEM.
Pour lire le résumé en anglais cliquer ici.
The genetic architecture of morphological, physiological and behavioral characters conditions and constrains the biodiversity of species and their ability to adapt to environmental changes. Gathering and processing qualitative and quantitative information about the genetic mechanisms that underly a trait of interest is thus of tremendous importance in plant and animal breeding, medicine, and evolutionary genetics. However, the complexity of genetic architectures is overwhelming. Recent advances in molecular biology, evo-devo and quantitative genetics have indeed highlighted how intricated were genetic, metabolic and developmental regulation mechanisms in the expression of the gene-to-phenotype relationship.
Evolutionary quantitative genetics aims at predicting the evolutionary properties of a population or a species without detailing explicitly the complexity of the genotype-phenotype relationship. To do so, the models that are frequently used do not pretend to provide an exhaustive description of the genetic architecture, but rather to summarize it through some simple parameters, expected to catch key properties of the genotype-phenotype map in a population. The sharp contrast between the complexity of real architectures and the simple picture provided by most quantitative genetics models has often lead to some debate on the relevance of qualitative and quantitative predictions derived from the mathematical simplification of the evolutionary theory.
The philosophy of this project is to challenge the capacity for some widely used models to describe and predict the evolutionary potential of populations and species, by contrasting their predictions with empirical data and/or more realistic models. The research objectives thus focus on the validation and the improvement of the part of the theory of evolution dealing with the complexity of genotype-phenotype maps.