The anisotropic diffusion is caused by the reduction of exchange between the ER in the anterior and posterior domains of the embryos. The size of the ER compartments is par-3 dependent. (A) The AIs quantified for the embryos photobleached at 32% (position 1) and 22% (position 2) of egg length in the anterior domain and 76% (position 3) of egg length in the posterior domain using the indicated measurement regions. These regions are either located in the opposite compartments (x, θ, and γ) or within the same compartment (λ, µ, and β). Orange circles indicate photobleached areas; blue squares indicate the measurement regions on the A-P axis; red squares indicate the measurement regions on the perpendicular axis. n_position1 ≥ 19; n_position2 > 34; n_position3 = 26. Mann-Whitney test; *, P < 0.05; **, P < 0.01. Unpaired t test; ****, P < 0.0001. (B) The AIs quantified for par-3(RNAi) (n_anterior = 33; n_posterior = 28) and par-2(RNAi) (n_anterior = 17; n_posterior = 16) embryos expressing GFP::SP12 in comparison with their Ctrl(RNAi) (n = 17–31). Unpaired t test; *, P < 0.05; **, P < 0.01. ns, not significant. All AIs shown are on log₂ scale. All graphs show mean ± SD.