digraph finite_state_machine {
	rankdir=LR;
        {
		node [style = invis]; I;
	}
	node [shape = doublecircle]; 3;
	node [shape = circle];
        I -> 0
	0 -> 1 [ label = "A" ];
	0 -> 1 [ label = "C" ];
	0 -> 1 [ label = "G" ];
	0 -> 1 [ label = "T" ];
	1 -> 2 [ label = "T" ];
	2 -> 3 [ label = "G" ];

}