Epigenetics
The best example of epigenetic changes in eukaryotes is the process of cell differentiation, where a less specialized cell becomes more specialized. During morphogenesis, generalised stem cells become the cell lines of the embryo which in turn become fully differentiated cells. In other words, a single fertilized egg cell – the zygote – divides and changes into all the many cell types: neurons, muscle cells, epithelium, blood vessels etc.