Soon after fertilisation, a critical portion of the embryonic genome is switched on through the actions of maternally inherited Stella, in part through controlling the activation of transposable elements.
To protect the germ line genome, chickens acquire new small RNA-based immune defense in response to recently endogenized retroviruses by turning a truncated provirus into a weapon.
The maternally provided histone demethylase LSD1/KDM1A has an instrumental role at the beginning of life, shaping the histone methylation landscape and the transcriptional repertoire of the early mouse embryo.