The marked reduction in the number of definitive erythrocytes in the peripheral blood ofjmj^trap/trap embryos. Representative photographs of erythroid cells from the peripheral blood of control (jmj^+/+) embryos (A) andjmj^trap/trap embryos (B) at 14.5 dpc are shown. D and P indicate a definitive erythrocyte and a primitive erythrocyte, respectively. Scale bar, 50 μm. (C) The numbers of erythrocytes in the peripheral blood of 14.5 dpc and 15.5 dpc embryos (genotypes shown below). eryD and eryP indicate definitive erythrocytes and primitive erythrocytes, respectively.