Muscle cells But if in the same organIsm, should have the same DNA per Nerve cells( cell Different cells have different clusters of genes active Development and differentiation of embryos is controlled by signaling molecules that alter gene expression in cells 2005-11-11 Chaoqun Wu, Fudan University2005-11-11 Chaoqun Wu, Fudan University Chaoqun Wu, Fudan University 3 Muscle cells Nerve cells But if in the same organism, should have the same DNA per cell Different cells have different clusters of genes active Development and differentiation of embryos is controlled by signaling molecules that alter gene expression in cells