Heritability of Threshold Characters.

Abstract

The amount of selection pressure applied on the phenotypic level to metric characters can be expressed in terms of the selection differential, defined as the extent of superiority of the individuals which are the parents of the next generation (weighted for the relative number of offspring they produce) over the average of their own generation. For characters showing a discontinuous distribution, the measurement of selection pressure can be expressed in terms of selection coefficients, that is, the relative number of offspring produced by each of the phenotypically classified categories of individuals in the population.