dSK⁻, dSlo⁻, and dSK⁻;; dSlo⁻ photoreceptors have normal morphology, LICs, but 8%–40% reduced light-insensitive I_A currents. A, The mutant retinae appear structurally intact, with R1–R7s having WT-like rhabdomeres and pigmentation. Scale bars (EM), 1 μm. B, Whole-cell recordings were performed from dissociated ommatidia. C, Mutant and WT R1–R6 QB waveforms and their amplitude distributions to dim flashes are similar. D, WT and dSK⁻;; dSlo⁻ R1–R6 LIC responses to 1 s light pulses of different brightness. E, Macroscopic LIC peak and plateau responses were similar, with the normal experimental variation, indicating that dSK and dSlo deletions do not affect phototransduction. The smaller dSlo⁻ maximum LIC probably resulted from these ommatidia being smaller, reflecting dSlo⁻ mutants reduced yield/health. F, WT and mutant R1–R6s' voltage-sensitive outward K⁺ currents to increased voltage steps contain both the transient Shaker (I_A) and sustained delayed rectifier, Shab (I_KS) components. G, dSK⁻ R1–R6 K⁺ currents have a reduced I_A but near normal-sized I_KS. H, On average, the maximum I_A and I_KS currents in dSK⁻ and dSlo⁻ R1–R6s are a bit smaller than the WT (dSK⁻ I_A: 36.4% < WT; I_Ks: 24.9% < WT; dSlo⁻ I_A: 30.6% < WT; I_Ks: 19.0% < WT) but WT-like in dSK⁻;; dSlo⁻ R1–R6s. n.s., non-significant.