Genetic Map of the nif D Element. The positions of known nif D element genes and other open reading frames are indicated with arrows showing the orientation. LB = left border, RB = right border, H = Hin dIII sites. The numbers inside the double lines designate the Hin dIII fragment subclones of the nifD element derived from a 17 kbp Eco RI fragment, An 207. The cyp110 probe was made from the An207.4 Hin dIII fragment. The complete sequence of the nif D element is deposited in Genbank (U38537).