Flies whose eyes are homozygous for sec15² (due to somatic clones induced using Scer\FRT and Scer\FLP1^ey.PN) exhibit reduce phototaxis in response to red and blue light. Electroretinograms of these animals show normal depolarisation in response to light but an absence of on and off transients.

Most wild-type lamina cartridges have 6 photoreceptor terminals per cartridge, with a few having 5 or, very occasionally, 7. Flies whose eyes are homozygous for sec15¹ (due to somatic clones induced using Scer\FRT and Scer\FLP1^ey.PN), numbers of photoreceptor terminals per cartridge range from 2-8 and are relatively evenly distributed throughout this range (4-6 is most common, 2 and 8 less). However, these terminals form morphologically normal synapses in normal numbers per terminal. Experiments with chimeric eyes in which about 50% of photoreceptors are in sec15¹ homozygous clones indicate that these neuroanatomical defects are cell autonomous.

Sec15² is a suppressor | partially of lethal - all die before end of pupal stage phenotype of Scer\GAL4^dpp.blk1, dpp^UAS.E.EGFP