Sex Influenced Traits in Poultry

Sex-Influenced Traits in Poultry: Hen Feathering, Genetics, and Examples

Sex-influenced traits in poultry are controlled by autosomal genes, but their phenotypic expression varies according to the sex of the bird. Hen feathering is a classic example, illustrating how the same genotype can produce different phenotypes in males and females.

Unlike sex-linked traits, these traits are carried on the autosomes. Here, the phenotypic expression of the genotype depends on the sex of the bird. A typical example is hen feathering. In Andalusian, Polish, and Hamburg breeds, both males and females have the same type of feathering, known as hen feathering. No sexual dimorphism is observed in these breeds with respect to the feathering pattern.

The hen-feathering gene (H) is dominant over the cock-feathering gene (h). It can also be considered sex-influenced in its phenotypic expression; all females are hen-feathered irrespective of their genotype, whereas males with the “HH” and “Hh” genotypes are hen-feathered, and those with the “hh” genotype are cock-feathered.

Hence, the phenotypic expression of the genotype depends on the sex of the bird.