Loss of Hhex expression affects hemangioblast development. (A) Representative flow cytometric profile of the frequency of Flk-1⁺ hemangioblast on days 0 and 5 of coculture from wt and Hhex^−/− Jet ES cells. (B) Overall frequency of Flk-1⁺ cells on days 4 through 6 of coculture from wt Jet (gray) and Hhex^−/− (black) Jet ES cells (n = 5). Error bars represent SD. *P ≤ .005. (C) Total number of Flk-1⁺ cells on days 4 through 6 of coculture. *P ≤ .005. Error bars represent SD. SSC indicates side scatter.