Relationships Between Genetic Parameters in the Component Traits of a Ratio Trait and the Distribution and Heritability of Such Ratio Trait.

The relationships between the distribution and heritability of a ratio trait and the genetic parameters of its component traits were clarified using a Monte Carlo computer simulation. The component traits of a ratio trait were assumed to be normally distributed. The genetic parameters of the ratio trait were estimated using parent-offspring regression. As the genetic and environmental correlations ( and ) of the component traits increased, the variance, skewness, and kurtosis of the ratio trait decreased. The amount of decrease had a greater effect on than on . The estimated heritability of the ratio trait decreased as increased and as decreased. The estimated heritability of a ratio trait can be higher than the heritability of any of its component traits.