Migration of definitive HSPCs to the PBI. *EGFP positive cells in the anterior part of ventral wall of DA in the 30hpf Tg(fli1:eGFP) embryos were uncaged. Embryos were then fixed at either 2dpf or 3dpf for double staining against flu and c-myb. The ratio indicates the number of embryos containing flu/c-myb double positive cells found in the corresponding region versus the total number of embryos examined. †Cells in the PBI and trunk region between dorsal aorta and posterior cardinal vein were uncaged at 3dpf. Embryos were survived to 5dpf for double staining against flu and ragI. The ratio indicates the number of embryos containing flu/ragI double positive cells in the thymus versus the total number of embryos examined.