In stage 11 embryos, sob is expressed in stripes that are adjacent and posterior to hh-expressing cells in each parasegment. It is also expressed in the presumptive hindgut.

The odd, sob and drm transcripts are detected an identical pattern in the third instar leg disc. There is segmental expression manifested as concentric rings on the distal edges of each presumptive leg segment not including the 4 tarsal segments (i.e. 5 rings of expression). There is an additional area of expression in the center of the disc that may correspond to a track of glial cells. The expression of drm is observed to begin during early larval development as a proximal ring of expression corresponding to the coxa. As larval development proceeds additional rings of expression are observed until the full complement of five rings is observed. Expression of odd, sob and drm occur in cells that are adjacent and distal to cells expressing the N ligands, Dl and Ser.

At the cellular blastoderm stage, sob transcripts accumulate in 7 transverse stripes that are 3-4 cells wide and correspond to the odd-numbered segments. A domain of expression is also observed at 85-100% egg length. At around the time of gastrulation, the stripe pattern changes to a segment polarity pattern of 14 stripes. The sob stripes are relatively weak in the blastoderm stage and gain in intensity when they are expressed in the segment polarity pattern. The sob expression pattern overlaps that of odd at these stages. In later stages, sob continues to be expressed in the epidermis but is also expressed in the proventriculus, proximal Malpighian tubules, brain, and pharyngeal muscles.