Seminars

 Recent studies in our group have described a unique form of imprinting in diploid sporophytes of Marchantia polymorpha where the whole paternal genome is silenced by the histone post-translational modification H3K27me3, in a process termed Paternal Chromosome Repression. This imprinting is lost amidst chromatin reprogramming triggered at meiosis and continued during sporogenesis, leading to the reset to the vegetative landscape of the gametophyte in the mature spore. Epigenetic reprogramming is a key process to erase the previous generation’s epigenome and to establish totipotency for the establishment of a whole new organism. The specific contributions of meiosis in epigenetic reprogramming have been difficult to study in other model organisms for the majority of which meiosis happens in close temporal proximity with gametogenesis and fertilization. In contrast, Marchantia, in which these processes happen at distinct times of the life cycle, is a very powerful model to address this question. Following on from our previous work, we are working on determining the precise correlation between reprogramming and meiosis, by dissecting the molecular pathways responsible for the triggering of the reprogramming at this time and characterizing the chromatin machinery involved in this phenomenon.