Table 3.

Genotype of E15.5–18.5 embryos obtained from Brg1-Brm double heterozygous intercrosses

Genotype		Expected^	Observed#	Exencephalic	Observed/Expected
Brg1	Brm
+/+	+/+	1/12 (.083)	23 (.144)	0/23	1.7**
+/+	+/−	2/12 (.167)	22 (.138)	0/22	0.8
+/+	−/−	1/12 (.083)	15 (.094)	0/15	1.1
+/−	+/+	2/12 (.167)	36 (.225)	3/36	1.3
+/−	+/−	4/12 (.333)	47 (.294)	3/47	0.88
+/−	−/−	2/12 (.167)	17 (.106)	1/17	0.63*

^#A total of 160 embryos were genotyped.

^{^}Because Brg1^−/− is lethal, no embryos were observed for this genotype regardless of Brm genotype (+/+, +/−, or −/−), and the absence of these mice were taken into account when determining the expected genotypic frequencies.

^*p < 0.05 and

^**p < 0.005 based on chi-squared goodness-of-fit statistical tests