Table I. Measurements of proliferation and apoptosis in mutant and control nerves.

	BrdU incorporating nuclei		TUNEL-positive cells
Age	mt	wt	mt	wt
	%	%	%	%
E15.5	24.6 ± 3.4(10)	23.7 ± 3.0 (11)	1.95 ± 0.67 (32)	1.96 ± 0.75 (12)
E17.5	35.5 ± 2.5(6)	28.3 ± 3.6 (7)	0.21 ± 0.17 (24)	0.18 ± 0.10 (23)
P5			0.74 ± 0.18 (14)	0.54 ± 0.12 (11)

Percentages (mean ± SEM) of nuclei incorporating BrdU and of TUNEL-positive cells in nerves of mutant (mt) and control (wt) mice. Number of experiments is in parentheses. By a paired, two-tailed t test, the percentages in mutant and control animals were not significantly different.