The field of epigenetics is young and quickly expanding. During the last year alone, thousands of research articles considered epigenetic mechanisms and their phenotypic consequences in different animal and plant species. Various definitions have been given, though, as to what precisely is epigenetics. Recent ones take into consideration that chromatin at genes and chromosomal regions can be structurally organised by covalent modifications and nuclear proteins, and via RNA molecules, in order to achieve defined expression states that can be perpetuated. Such somatically and meiotically heritable effects on gene function have diverse biological and medical implications. In particular, they are known to be important in development. A recent discussion meeting in Paris at the French Academy of Sciences reviewed our current understanding of ‘Epigenetics and Cellular Memory’ and where this novel discipline in life sciences is heading. To cite this article: R. Feil, C. R. Biologies 331 (2008).