Table 2. Table 2. Heterozygote advantage for fecundity in sheep under two different environment conditions.
Environment | Birth category | Total | |||
Single | Twins | Triplets | |||
Proportions for wildtype (+/+) | 0.26 | 0.67 | 0.07 | 1 | |
Proportions for heterozygote (+/−) | 0.19 | 0.55 | 0.26 | 1 | |
Mean survival rate to weaning | Intensive Farming | 0.9 | 0.85 | 0.65 | 0.8 |
Mean survival rate to weaning | Harsh Hill Country | 0.75 | 0.65 | 0.35 | 0.58 |
Surviving lambs for wildtype (+/+) | Intensive Farming | 0.23 | 1.14 | 0.14 | 1.51 |
Surviving lambs for heterozygote (+/−) | Intensive Farming | 0.17 | 0.94 | 0.51 | 1.62 |
Surviving lambs for wildtype (+/+) | Harsh Hill Country | 0.20 | 0.87 | 0.07 | 1.14 |
Surviving lambs heterozygote (+/−) | Harsh Hill Country | 0.14 | 0.72 | 0.27 | 1.13 |
a) Predicted proportions and survival to weaning by birth category for carriers of the Inverdale mutation (FecXI) and for wildtype Romney sheep for the two environmental extremes, intensive farming and harsh hill country. |