Restriction enzyme map of the AZU1-PRTN3-ELA2-ADN (APEA) locus. Cosmids used to identify the relative position of the ADN gene to the known genes in the locus are shown as thin horizontal lines above the restriction map. Restriction sites mapped are indicated. (B, BamHI; N, Not I; R, EcoRI; S, Sal I). Relative positions of the identified exons are shown for ADN (thick lines), and also for AZU1, PRTN3, and ELA2.