Table 1.

Distribution of genotypes

Genotype		Embryos at 14 days		Pups at birth		Pups at 3 weeks
c-Abl	p53	Observed	Expected	Observed	Expected	Observed	Expected
+/+	+/+	2	3.68	10	3.63	6	6.01
+/+	+/−	4	7.38	3	7.25	13	15.50
+/+	−/−	2	3.68	4	3.63	15	9.51
+/−	+/+	16	7.38	13	7.75	19	14.38
+/−	+/−	13	14.75	14	15.50	44	35.75
+/−	−/−	6	7.38	6	7.75	19	21.38
−/−	+/+	6	3.68	5	4.13	7	8.39
−/−	+/−	6	7.38	6	8.25	20	20.25
−/−	−/−	4	3.68	1  (NV)	4.13	0	11.89
Total		59*	59	62†	62	143‡	143

Embryos and pups were genotyped with PCR-based methods at the indicated time points. The expected distribution of genotypes was calculated, assuming independent, Mendelian inheritance of each allele. Because some of the crosses involved homozygous mice (c-Abl−/− p53+/− or c-Abl+/− p53−/−) to increase the probability of producing c-Abl−/− p53−/− mice, the expected number of c-Abl−/− p53−/− mice is greater than 6.25% expected from crosses with c-Abl+/− p53+/− mice alone. P values are derived from χ² analysis and show that the difference between observed and expected is statistically significant for pups at birth and 3 weeks but not for embryos at 14 days. *Not significant (P > 0.05); †, P < 0.01; ‡, P = 0.0131; NV, nonviable.