Quantitation of functional HSCs and HPCs in G2V embryonic hematopoietic tissues. HSCs in sorted Venus⁺ and Venus⁻ cell fractions of E11 AGM were analyzed by transplantation into irradiated adult recipients. (A) Percentage donor cell chimerism was determined by Venus PCR of peripheral blood DNA at 4 months after transplantation. Each dot represents 1 recipient receiving 1.7 to 6.5 embryo equivalent (ee) of AGM cells. n = 7. **P = .0089. (B-F) Hematopoietic progenitor number per tissue in sorted Venus⁺ and Venus⁻ cell fractions of (B) E9 and E10 AGM, (C) E9 and E10 VA+UA, (D) E9 and E10 YS, (E) E9 and E10 PL, and (F) E10 FL. CFU-C per 1 ee of tissue is shown. Colony types designated by colored bars are CFU-granulocyte, erythroid, monocyte, megakaryocyte (GEMM); CFU-granulocyte, macrophage (GM); CFU-macrophage (M); CFU-granulocyte (G), and burst forming unit-erythroid (BFU-E). SEM of total CFU-C is shown; 2 ee of somite pair–matched tissues were pooled for sorting and yielded 1 ee for colony analysis.