Coculture of AGM cells with stromal cells. (A) Embryo 10.5 dpc AGM cells were cocultured with the murine stromal cell line, OP9, in the presence of IL-3. Small round cells were generated for 14 days’ culture. (B) Hematopoietic cells generated on OP9 cells (middle). Without OP9 cells, fibroblast-like cells grew slowly to be confluent in 4 weeks (right).