A Strategy for Studying Epigenetic Diversity in Natural Populations: Proof of Concept in Poplar and Oak.

These last 20 years, several techniques have been developed for quantifying DNA methylation, the most studied epigenetic marks in eukaryotes, including the gold standard method, whole-genome bisulphite sequencing (WGBS). WGBS quantifies genome-wide DNA methylation but has several inconveniences rendering it less suitable for population-scale epigenetic studies. The high cost of deep sequencing and the large amounts of data generated prompted us to seek an alternative approach. Restricting studies to parts of the genome would be a satisfactory alternative had there not been a major limitation: the need to select upstream targets corresponding to differentially methylated regions (DMRs) as targets. Given the need to study large numbers of samples, we propose a strategy for investigating DNA methylation variation in natural populations, considering the structural complexity of the genomes with their size and their content in unique as coding regions versus repeated regions as transposable elements. We first identified regions of highly variable DNA methylation in a representative subset of genotypes representative of the biological diversity in the population by WGBS. We then analysed the variations of DNA methylation in these targeted regions at the population level by Sequencing Capture Bisulphite (SeqCapBis). The entire strategy was then validated by applying it to another species. Our strategy was developed as a proof of concept on natural populations of two forest species: Populus nigra and Quercus petraea.

Chimiotherapie des cancers du col de l'uterus au stade IV a vesical a l'Institut Curie de Dakar

Les cancers du col de l'uterus au stade IV ne relevent plus de la combinaison standard radio-chirurgicale. Aussi dans notre contexte marque par les difficultes de tous ordres pour correctement appliquer la chimiotherapie; nous avons pense opportun de retracer notre experience dans l'utilisation de moyen therapeutique dans les cancers du col uterin classes IVa vesical a Dakar. Sur 91 dossiers retenus; 80 ont concerne la mise en oeuvre de la combinaison chimiotherapie et radio-therapie selon diverses modalites. Les resultats enregistres dans la pratique de cette modalite nous poussent a proposer la procedure chimiotherapie neoadjuvante suivie de radiochimiotherapie dans notre contexte en l'absence de curietherapie pour ameliorer la survie