DNA Testing – Chocolate Feather Gene

Chocolate Feathering Test (TYRP1 Gene – Sex-Linked Recessive Mutation)
The chocolate feathering trait in chickens is caused by a sex-linked recessive mutation on the TYRP1 gene, located on the Z chromosome. This mutation dilutes black pigment (eumelanin), resulting in a rich chocolate-brown coloration instead of solid black.

Because it’s sex-linked, the gene behaves differently in males and females:

• Males have two Z chromosomes (ZZ), and must inherit two copies of the chocolate allele (b/b) to display the trait.

• Females have one Z chromosome (ZW), so a single copy of the chocolate allele (b/-) is enough for them to express the phenotype.

This test detects whether the chocolate allele (b) is present or absent in your bird’s DNA.