Ueli studies the role of epigenetics in plant sex. In mammals and plants, mum and dad’s genomes have conflicting interests regarding the amount of nutrients mum provides to her children. Such parental conflict is thought to have led to the evolution of imprinting, whereby genes are active depending on their parental origin. Ueli has discovered an imprinted plant gene called Medea, which is only active when maternally inherited. Similarly to many mammalian imprinted genes, Medea restricts embryonic growth. If a mutated Medea gene is inherited from mum, embryos grow too large and die. Thus, as in ancient Greek mythology, Medea kills her own children.