Fig. 2. (A) Flow cytometric analysis of E11.5 AGM region demonstrating endothelial (VE-cadherin⁺CD45^-; R1), haematopoietic (VE-cadherin^-CD45⁺; R3) and double-positive (DP) (VE-cadherin⁺CD45⁺; R2) cell populations. The contour plot shown is a representative example compiled from approximately 10e.e. of E11.5 AGM (1.5x10⁶ cells). (B) The endothelial affiliation of the double-positive population extends beyond the expression of VE-cadherin, demonstrated by endothelial-like levels of TIE2, FLK1, PECAM1, Ac-LDL, CD34 and SCA1 expression. The DP and the endothelial populations largely share endothelial and stem cell markers. Isotype control (white) and specific antibody staining (grey) are presented. The analysis of DP, endothelial and haematopoietic populations was made using data from 200-700, 15,000-20,000 and 9000-30,000 live cells, respectively. All data are representative of two to four experiments for each marker analysed.