Table 1. Ndr1/2-double null mice are embryonic lethal, but a single Ndr allele is sufficient to sustain normal development.
| Ndr1 GT | Ndr1+/+ | Ndr1+/+ | Ndr1-/- | Ndr1-/- | Ndr1+/+ | Ndr1+/- | Ndr1-/- | Ndr1+/- | Ndr1+/- |
|---|---|---|---|---|---|---|---|---|---|
| Ndr2 GT | Ndr2+/+ | Ndr2-/- | Ndr2-/- | Ndr2+/+ | Ndr2+/- | Ndr2-/- | Ndr2+/- | Ndr2+/+ | Ndr2+/- |
| offspring numbers | 37 | 23 | 0 | 28 | 44 | 54 | 42 | 53 | 134 |
| theoretical (%) | 6.25 | 6.25 | 6.25 | 6.25 | 12.5 | 12.5 | 12.5 | 12.5 | 25 |
| actual (%) | 8.92 | 5.54 | 0.00 | 6.75 | 10.60 | 13.01 | 10.12 | 12.77 | 32.29 |
Genotype (GT) distribution of offspring from Ndr-single allele intercrosses (Ndr1 +/-;Ndr2 -/- x Ndr1 -/-;Ndr2 +/-) at weaning. Actual offspring numbers are indicated, together with the expected and obtained Mendelian ratios. No Ndr1/2-double null mice were recovered. All other genotypes were obtained at approximately the expected Mendelian ratios. A total of 415 offspring were analyzed (n = 415).