Ets1^−/−;Ets2^A72/A72 embryos have defects in vessel branching and reduced vascular complexity. E10.5 mouse embryos were analyzed by immunohistochemistry with anti–PECAM antibody in whole mount. Controls are in top row (WT), and Ets1^−/−;Ets2^A72/A72 embryos are in lower row (DM). Arrowheads highlight examples of vessel branching in control embryos that are absent in the double-mutant embryos. Bars, 0.25 mm.