An embryo develops from a group of pluripotent cells into a differentiated organism. This transition from pluripotency to differentiation is dependent on the presence of transcription factors such as OCT 4 and NANOG. Also signaling molecules are involved and so are epigenetics. By means of transcriptome, epigenome and proteome analysis in embryos and embryonic stem cells, we aim to unravel the pathways involved this process.