Knockout of bcas2 affects definitive hematopoiesis. (A-B) The bright field images showed developmental defects in bcas2^−/− zebrafish at 5 dpf. (C-L) Whole-mount in situ hybridization showed defective definitive hematopoiesis as shown by the alteration of (D) cmyb, (F) hbae1, (H) mpx, (J) lyz, and (L) rag1 in bcas2^−/− mutants compared with corresponding sibling embryos (C,E,G,I,K). Thymus epithelial cell marker foxn1 is expressed normally in the thymus at 4 dpf (M-N). Numbers at the bottom right indicate the number of embryos with similar staining patterns among all embryos examined. Black arrows indicate HSPCs in the CHT; red arrows indicate HSPCs in the thymus. Scale bar, 200 μm.