Additive and Dominance Effects of Genes in Egg Production and 10-Week Body Weight of Crossbred Chickens

Abstract

THE hereditary variation of a quantitative character can be divided into additive and non-additive portions. The additive portion of variation is contributed by the additive effects of gene actions, while the non-additive portion is from the interactions of genes. There are two types of gene interactions—dominance and epistasis. The dominance effect is from the interaction between the allelic genes (loci), while the epistatic effect, from the interaction of non-allelic genes (loci). The heritability estimate (in a narrow sense) of a character for a certain population represents the additive effects of genes, while heterosis in the crossbred progenies indicates the dominance and epistatic effects of genes. Heritability of egg production and body weight of chickens has been estimated by a number of investigators (see Shoffner and Sloan, 1948), while the heterotic effects of genes for these two characters have also been studied (Dickerson et al., 1950; Hutt and Cole, 1952; …