Map of the opossum TRA/TRD locus. TRAV (red), TRDV (yellow), TRDJ (light green), TRAJ (dark green) and TRDD (orange) gene segments are shown numbered by their location in order across the locus. TRV segments are designated with the subgroup number followed by a period and a designated number according to their location. TRA segments that were also found expressed with TRDC, and therefore TRA/DV, have diagonal yellow stripes. TRDC (light blue) and TRAC (dark blue) are also indicated. Transcriptional orientation is indicated by the direction of the arrow on each segment. Presumptive pseudogenes are indicated with a ψ. Syntenic genes discussed in the text are indicated in gray.