The fundamental organization of the DNA in active and inactive compartments arises immediately after fertilization of the oocyte, even before genes are activated. This was discovered by researchers from the Hubrecht Institute and the Helmholtz Center Munich and will lead to a better understanding of the mechanisms behind the development of a single fertilized oocyte into a complete organism that consists of many different cell types. The results were published in the scientific journal Nature on the 22nd of May.