To understand whether aberrant OC cell proliferation may be involved in coloboma formation in the Foxg1−/− mutant, we calculated the LI (BrDU-positive cells over total number of cells) in nasal and temporal retinae of E10.5 wild-type and Foxg1−/− mutant OCs (for a detailed description, see Materials and Methods). The gene discussed is FOXG1; the disease is coloboma.