RAI14 in the blood feather regulates chicken pigmentation

A genome-wide association study (GWAS) was performed on a resource family consisting of white and colored chickens for identification of genes related to plumage coloration using the Fixed and random model Circulating Probability Unification (FarmCPU) package. GWAS identified three chromosomal single-nucleotide polymorphisms (SNPs), demonstrating the polygenic basis of plumage phenotypes. Herein, retinoic acid-induced protein 14 (RAI14), a developmentally regulated gene that encodes a protein containing many ankyrin repeats, was identified as a candidate gene involved in plumage color. In this study, mRNA expression profiles of chicken RAI14 were determined, indel (insertion-deletion) variants were identified, and their association was analyzed in white and colored chickens. RA114 mRNA was expressed in all tissues tested (brain, spleen, liver, heart, oviduct, kidney, lung, pituitary gland, ovary, muscle, feather bulb, and skin). A relatively high RAI14 expression in white feather bulb compared to colored feather bulb ( $$ ) indicated a potential association with plumage color. Additionally, statistical analysis revealed that a 4 bp indel genetic variation in RAI14 was associated with plumage phenotypes ( $$ ). Together, our analysis of the identification of the RAI14 gene will enable us to understand the genetic mechanisms behind chicken pigmentation.