Well, differential gene expression is actually what allows a cell that has been determined to produce that specialized type of cell. So let's suppose we have the following diagram. So in this diagram we have an unspecialized cell that undergoes cell determination and that process chooses pathway one. Now we have a second type of unspecialized cell and the same type of cell is here. But this cell chooses pathway number two. So pathway number one leads to a neuron while pathway number two leads to a skeletal muscle cell.