Apoptosis and cell proliferation are not statistically different in the rhombic lip of normal and mutant animals.

Normal-mutant pairs (8–10) of littermates from 8 litters were analyzed for apoptosis by TUNEL assay and for cell proliferation by phospho-Histone3 immunohistochemistry as described in the Methods section. Between 76 and 104 sections were examined and the number of positive cells that labeled in the relevant assay in each section were scored. The average number of positive cells per section are shown with the standard deviation (SD). The statistical significance for each grouping (Assay and Genotype) were assessed by Student t-test.