Virtual creatures, with muscles, senses and primitive nervous systems, have been “grown” from artificial embryos in a computer simulation. The multi-celled organisms could be the first step towards using artificial evolution to create intelligent life from scratch.
Each creature begins life as a single “embryo” cell, containing a string of random numbers that represent its genome. Some genes tell the cell to split in two, forming a joint between the two new cells. Others tell it to develop different kinds of ability to make the organism move within or sense its virtual environment.
Given a particular genome, each embryo cell will develop in a predetermined way. More here.