Phenotype variation is due to the additive effects of geneti…

Phenotype variation is due to the additive effects of genetic variance and environmental variance.  In an inbred of mice, the variance for the body fat was 325.  Under the same environmental condition, the variance for body fat of genetically heterogeneous mice was 1000.  The genetic variance for the heterogeneous mice is

To estimate the heritability of maze-learning ability in rat…

To estimate the heritability of maze-learning ability in rats, a selection experiment was carried out. From a population in which the average number of trials necessary to learn the maze was 10.8.  Animals were selected that managed to learn the maze in an average of 5.8 trials.  Their offspring required an average of 8.8 trails to learn the maze.  Calculate the narrow-sense heritability of maze-learning ability in this population.