Table 1.

Percentage of mice of each genotype determined prenatally, immediately postnatally, and at weaning

Age	n	Percent of animals
		+/+	+/−	−/−
Prenatal E12.5–E19.5	111	23	56	21
Postnatal 0–8 hr	34	32	50	18
Weaning, 3 weeks	72	35	65	0