Table 1.
Pet-1 mutant mice are born in normal Mendelian ratios but a significant subset die prematurely during the first postnatal week. (A) Genotype frequencies of wild type (+/+), heterozygous (+/−) and homozygous (−/−) Pet-1 mice at birth. The frequencies of +/+, +/− and −/− Pet-1 mice observed on the day of birth were not significantly different from expected Mendelian ratios in either the pathogen-exposed (PE) or pathogen-free (PF) colonies (χ2; PE, P=0.66, 2 df; PF, P=0.79, 2 df). (B) In both colonies, postnatal mortality rates of −/− mice were significantly greater than either +/+ or +/− animals, while the mortality rates of +/+ and +/− mice were not significantly different from one another. In addition, there was no significant difference in mutant mortality rates between the two colonies (χ2, P=0.83, 2 df).
| A Genotype Frequency | |||
|---|---|---|---|
| Genotype | Number born (n) | Frequency (%) | |
| PE | |||
| (+/+) | 96 | 23 | |
| (+/−) | 224 | 52 | |
| (−/−) | 107 | 25 | |
| PF | |||
| (+/+) | 71 | 25 | |
| (+/−) | 150 | 52 | |
| (−/−) | 65 | 23 | |
| B Mortality Rate | |||
| Genotype | Number born (n) |
Number of deaths |
Mortality (%) |
| PE | |||
| (+/+) | 81 | 4 | 5 |
| (+/−) | 174 | 12 | 7 |
| (−/−) | 80 | 25 | 31 |
| PF | |||
| (+/+) | 60 | 2 | 3 |
| (+/−) | 107 | 7 | 7 |
| (−/−) | 47 | 11 | 23 |