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Fig. 4. Blastopore gene expression scales proportionally with embryo size. Groups of embryos of a wide range of sizes from multiple clutches were fixed during mid-gastrula (st. 11) for wnt8a analysis (A–E) or early gastrula (st. 10.25) for chrd.1 (F–J), gsc (K–O) and admp (P–T) analysis by in situ hybridization with gene-specific probes. For each gene, a group of mix-sized embryos was processed for analysis. Based on calculated circumference, the lower 45th percentile comprised the small embryos, and the upper 45th percentile were the large embryos. The middle 10% were omitted from the analysis. For each embryo, the angle describing the expression domain, the embryo diameter and the diameter of the blastopore were measured. Plots comparing the calculated circumference (B, G, L, Q), the angle describing the expression domain (C, H, M, R), the calculated arc of the expression domain (D, I, N, S), and the percent circumference covered by the expression domain (arc)(E, J, O, T) between small and large embryos are shown. ∗∗, p < 0.01; ∗∗∗, p < 0.001; ∗∗∗∗, p < 0.0001; ns, not significant. |