Fig. 2. Groove markers in pair rule mutants. (A) Wild type. Seven additional stripes of Odd (blue) appear before germ band extension. En stripes (green) also appear at that stage. Cadherin, red. (B,B'') In stage 13 odd paired⁸ embryos, Ena (green; B") accumulates at junctions between Odd cells (blue). Cadherin, red. (B') Cross-section at the position of the yellow arrowheads in B. Slight depressions are present at the position of the Odd cells. (C) In runt³ stage 13 embryos, Crb (green; C') accumulates in Odd-expressing cells (blue). Cadherin, red. (D) Stage 13 Odd-lacZ/odd⁵ transheterozygous embryo. Residual Odd (red) correlates with remaining groove cells. Cadherin (green) and En (blue). (D') Cross-section at the position of the yellow arrowheads in D. No groove forms posterior to En-expressing cells where Odd is absent.