Epigenetic Reprogramming in Early Mammalian Embryogenesis: Comparative Insights from Human and Model Systems

Abstract

Erasure and reinstatement of the epigenetic effects of totipotency and lineage specifications is the main event in early mammalian embryonic differentiation and entails epigenetic reprogramming. Two large-scale DNA demethylation waves of the world, global chromatin remodelling, histone dynamics of change, genomic imprint reinstatement, and X-chromosome reactivation, are also characteristic of it. Although our knowledge of the mechanics is largely based on the murine models, the growing availability of the single cell and multi omics technology has shown that there are species and conservation regulatory properties in human embryos. It may also be added that timing, maintenance of the imprint, access to the chromatin and control of transposable elements is also varied and this aspect explains why direct extrapolation cannot be carried out on human beings using the mouse models. In addition, the imprinting disorders have been linked to the epigenetic reprogramming perturbations and assisted reproductive technologies can have an effect on it. The provided review is a comparative examination in specifics of the epigenetic reprogramming in the first mammalian growth that attempts to discover the common mechanisms, species peculiarities, technological progress, and more recent clinical applications. Other questions/ directions that have not been addressed include translational reproductive medicine and epigenome editing.