Epigenetic Tracking, a Method to Generate Arbitrary Shapes By Using   Evolutionary-Developmental Techniques
  This paper describes an Artificial Embryology method (called ``Epigenetic Tracking'') to generate predefined arbitrarily shaped 2-dimensional arrays of cells by means of evolutionary techniques. It is based on a model of development, whose key features are: i) the distinction bewteen ``normal'' and ``driver'' cells, being the latter able to receive guidance from the genome, ii) the implementation of the proliferation/apoptosis events in such a way that many cells are created/deleted at once, in order to speed-up the morphogenetic process. iii) the presence in driver cells of an epigenetic memory, that holds the position of the cell in the cell lineage tree and represents the source of differentiation during development. The experiments performed with a number of 100x100 black and white and colour target shapes (the horse, the couple, the hand, the dolphin, the map of Britain, the foot, the frog, the baby, the stomach, the french flag, the head) bring to the conclusion that the method described is able to generate any target shape, outperforming any other known method in terms of size and variety of the generated shapes. The interpretation of the proposed method as a model of embryogenesis and its biological implications are discussed. 
Alessandro Fontana