Wild type and Notch2 mutant, Pax2-expressing early renal epithelia are proliferating to a similar degree while Jagged1-expressing, Notch2-deficient clusters have few cycling cells. (A, B) Representative images of BrdU-incorporation (red) within the Jagged1-expressing clusters (green). Bar, 0.05mm. (C, D) Histogram of results from several embryos indicates the percentage of BrdU-labeled cells within the Pax2- or Jagged1 expressing domains. Data are presented as means +/- SEM (Standard error of the mean).