Figure 1. Individual electroretinogram records obtained under different light stimulation conditions from a wild-type fly -OR/Df(3R)E79, denoted as control and two hclB mutants—hclBT2/Df(3R)E79, a null mutant, and hclBT1/Df(3R)E79, denoted as hclB^T2 and hclB^T1, respectively. In A and B, electroretinogram (ERG) responses to 0.3 s and 2 s stimuli are represented, respectively. The numbers on the left denote test stimulus intensities (in log quanta s⁻¹ μm⁻²). Responses obtained under dark adaptation (left) and light adaptation with a background of 4.66 log quanta s⁻¹ μm⁻² intensity (right) are represented. It is seen that the receptor component of the ERG has similar amplitude in both wild-type and mutant flies, while the ON and OFF transients’ amplitudes are significantly greater in the hclB mutants. It can also be observed that the overall duration of the transients is increased in the mutant flies.