Table 3. Analysis of survival at two weeks of age in Creb1 ^MesKO; Crem ^+/− mice.

Cross	Litters	Pups	Average litter size	Creb1fl/fl; Dermo1+/+; Crem+/+	Creb1fl/fl; Dermo1+/+; Crem+/−	Creb1fl/fl; Dermo1Cre/+; Crem+/+	Creb1fl/fl; Dermo1Cre/+; Crem+/−	Loss of Creb1MesKO; Crem+/− pups
Creb1fl/fl; Dermo1Cre/+; Crem+/− × Creb1fl/fl; Dermo1+/+; Crem+/+	23	129	5.6	45 (28.5)	38 (28.5)	33 (28.5)	13 (28.5)	Significant loss p = 0.0005

The genotype of the progeny was determined as described in Materials and Methods at two weeks of age. The expected number of each genotype is indicated in brackets, and was calculated according to a predicted Mendelian allele inheritance ratio. Statistically significant deviations from the expected frequency was determined using a goodness-of-fit test with significance set a p < 0.05.