Figure 3.

Apc^Min/+ ↔ Apc^Min/+ ROSA26⁺ aggregation chimeras develop polyclonal intestinal tumors. Embryos from Apc^+/+ females in matings with Apc^Min/+ males were fused to embryos from Apc^+/+ females in matings with Apc^Min/+ ROSA26⁺ males. One out of eight aggregation chimeras will be composed of Apc^Min/+ and Apc^Min/+ ROSA26⁺ components. The intestines of these mice were patchworks because cells carrying the ROSA26⁺ transgene express LacZ and are blue following staining with 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-Gal). Tumors from these Apc^Min/+ ↔ Apc^Min/+ ROSA26⁺ aggregation chimeras are often heterotypic being composed of ROSA26^- (white) and ROSA26⁺ (blue) neoplastic cells (arrows).