"Before you read this paper"

DNA methylation is involved in regulation of a diverse range of biological processes in vertebrates, plants, and fungi. DNA methylation patterns dynamically change in a highly orchestrated way during development, suggesting the existence of the enzymes catalyzing DNA methylation.
Although the enzyme that maintains DNA methylation was found in the 1980's, de novo methyltransferases had not been discovered for a long time.
This breakthrough paper describes identification and characterization of the de novo DNA methyltransferases in mice. In this lecture, I will introduce the paper and the mechanisms, and then we will discuss the roles of epigenetic regulation in animal development.