The number of HSPCs was reduced in the CHT of bcas2^−/−zebrafish. (A-F) The WISH assay of definitive HSPCs using a cmyb probe from 2 to 4 dpf indicates that the number of HSPCs was decreased in the CHT of bcas2^−/− mutants from 3 dpf compared with siblings. Scale bars, 200 μm. (G-L) Live imaging showed that EGFP-positive HSPCs in bcas2^−/−/Tg (cmyb: EGFP) zebrafish begin to decrease noticeably in the CHT region from 3 to 4 dpf compared with siblings/Tg (cmyb: EGFP). Scale bars, 50 μm.