Initiation of definitive hematopoiesis is defective in etsrp morphants. (A-F) runx1, c-myb, and rag1 expression in control (A,C,E) and etsrp morphants (MO; B,D,F). (A-B) runx1 expression in the ventral wall of the DA (arrowhead) at 30 hpf. (C-D) c-myb expression in the ventral wall of the DA (arrowhead) at 40 hpf. (E-F) rag1 expression in the thymus at 4 days after fertilization (arrowheads).