Early hematopoietic markers are expressed in smad1 morphants and piggytail mutants at the 5-somite stage. Shown are representative embryos following in situ hybridization for various hematopoietic markers at 5 somites using control (uninjected) embryos (A,D,G,J), smad1 morphants (B,E,H,K), and piggytail (pgy/pgy) mutants (C,F,I,L). Transcripts were analyzed for gata1 (A-C), gata2 (D-F), lmo2 (G-I), and scl (J-L). Pgy/pgy embryos were identified by genotyping after hybridization. Smad1 morphants have a modest increase in gata1, lmo2, and scl expression, while pgy/pgy embryos have more caudal expression (◀) of these as well as gata2. In panels A and B, note the increase in gata1 expression in smad1 morphants; the length of the gata1 stripe is longer (B), indicated by the bars that denote the extent of expression in wt. In contrast, pgy/pgy embryos have a shorter region of gata1 expression (C). The anterior lateral plate mesoderm expression of these markers is not effected. In situ hybridization was also performed at the 15-somite stage to detect pu.1 transcripts. (M-O) Levels are equivalent in control embryos (M) and smad1 morphants (N), while pgy/pgy (O) do not express pu.1 (noted by ). Each panel is a representative of 50 to 75 embryos analyzed per sample. Embryos are oriented: panels A-L are anterior to the left; panels A-F are whole mount; panels G-L are flat mount; and panels M-O are anterior to the top, whole mount.