Fertilization of an egg by sperm is the beginning of new life. The maternal and paternal genetic information, that collectively store the body plan of the living being, are combined after fertilization. However, the DNA is still in an inactive state in the cell nucleus at this early stage of life. While the first division of the fertilized egg cell functions with the help of maternal factors stored in the egg, for further development of an embryo the synthesis of new embryonic products is necessary, which requires access to the DNA of the embryo. As shown in Science, Kikuë Tachibana and her team at the MPI of Biochemistry have now shown that pioneer factor Nr5a2 awakens the embryonic DNA.