Polymorphism in the <i>MLANA</i> gene and its association with feather pigmentation in Chinese yellow quail ( <i>Coturnix japonica</i> )

1. Melan-A <i>(MLANA)</i> plays a key role in the development of the melanosome, making it a strong candidate for the pigmentation phenotype observed in animals. The main purpose of this study was to analyse the relationship between <i>MLANA</i> gene polymorphisms and tyrosinase (TYR) enzyme activity in skin tissues and melanin content in dorsal down feathers of Chinese yellow quail.2. The coding sequence region of <i>MLANA</i> mRNA was cloned and sequenced to detect polymorphisms. The melanin content in down feathers of 266 Chinese yellow quails was analysed by spectrophotometry, and TYR enzyme activity was measured in dorsal skin tissues. The expression of <i>MLANA</i> mRNA in skin tissues of individuals with different genotypes was analysed using RT-qPCR.3. One non-synonymous single nucleotide polymorphisms (NSSNP; c.218T/A) was identified, which resulted in a Leu36Val mutation in the transmembrane helix region of the MLANA protein. This NSSNP significantly reduced the expression level of <i>MLANA</i> mRNA and TYR enzyme activity in dorsal skin tissues, leading to a significant reduction in melanin content in down feathers.4. The c.218T/A locus of the <i>MLANA</i> gene is closely related to the pigmentation TYR of the down feathers in Chinese yellow quail and can be used as a molecular marker locus for breeding pure feather colour in quail.