The 5-methylcytosine DNA glycosylase ROS1 prevents paternal genome hypermethylation in Arabidopsis endosperm

ROS1 promotes epigenetic symmetry between parental genomes in the endosperm by preventing CG methylation gain on the paternal genome. We conclude that ROS1 and DME act in a parent-of-origin-specific manner at shared endosperm targets, and consider possible implications for the evolution of imprinting mechanisms.