Table 1. Rod outer segment morphology.

Parameter	WT	GCAP1−/−
ROS length, µm	24.2±0.3 (n = 120)	25.1±0.2 (n = 116, P = 0.011)
ROS diameter, µm	1.35±0.02 (n = 35)	1.30±0.01 (n = 74)
Disk repeat distance, Å	277±5 (n = 25)	337±2 (n = 36, P = 1e−18)

Measurements were made on rods from the central retina of 2 or 3 mice of each type, aged 2–3 months (representative sections are shown in Fig. 2F, G ). Data are given as mean ± SEM, (number of rods measured, P-value from a t-test for values less than 0.05).