Fig. 3. Frequency of tetraploid cells in the neocortex. The frequency was determined for BrdU-incorporating (R1) and non-incorporating (R2) populations by 7-AAD staining. The averages of R1 and R2 in three independent analyses were 7.3 and 6.6% in wild type (A), 8.2 and 7.3% in Emx2 single mutants (B) and 7.9 and 5.8% in Emx1/2 double mutants (C), respectively.