Structure of daf-16 isoforms. Coding regions are orange-filled boxes, and introns are lines. The SL1 trans-spliced region is indicated with a green line. The SL1 trans-spliced reads for the different isoforms are: daf-16d/f, 8 reads; daf-16d, 9 reads; daf-16a, 208 reads; daf-16b, 14 reads. See Additional file 1: Table S1 for ESTs associated with the different isoforms.