Stronger down-regulation in clo at 14 somites than at 36 hpf reveals early hematopoietic and vascular genes. (A) Genes in this cluster are marked by a predominant decrease in expression in clo^m39 at 14 somites (som). Fold changes are shown as log2 (mutant/WT, or morphant/uninjected). Blue and yellow boxes indicate decreased and increased gene expression, respectively, in mutant compared with WT (morphant compared with uninjected) embryos. The expression of genes highlighted in red is illustrated by in situ hybridization in panels B, C, and D. (B) At 14 somites, transcripts of Dr.194 96.1.A1 are present in the ICM of WT (arrowhead), but not in clo^m39. (C) At 36 hpf, expression of Dr.194 96.1.A1 is weakly detected in vasculature and in circulating erythrocytes (arrowheads) of WT embryos, but almost completely absent in clo^m39. Additional expression of Dr.194 96.1.A1 in epidermal cells, in the brain, and in the eye is present in both WT and clo^m39. (D) Higher magnification of panel C. Transcripts of Dr.194 96.1.A1 are detected in circulating erythrocytes (arrowhead) on the yolk sac of WT, but not of clo^m39 embryos at 36 hpf.