Research Note: Combined analysis of BSA-seq based mapping and RNA-seq reveals candidate genes associated with sub-Columbian plumage in H line chickens.

Columbian coloration patterns in plumage are widespread phenomena in several standard breeds of poultry, such as the Columbian Plymouth Rock chicken. H line chicken plumage is generally a pure white except in the hackle, wing, and tail plumage, which coloration is very similar to the Columbian plumage pattern, but with the barring substituting for the black vertical striping. Thus, we refer to this plumage coloration as "sub-Columbian" pattern. However, the genetic basis of this phenotype remains unknown. Here, a F3 cross population between yellow plumage roosters and sub-Columbian plumage hens was constructed, for verifying sub-Columbian plumage was sex-linked dominant inheritance. To identify the candidate regions, F2 generation sub-Columbian plumage hens and yellow plumage hens with their parental lines were used for BSA-seq, and sub-Columbian plumage genes were mapped to a 10.46 Mb interval on chromosome Z. Remarkably, by transcriptome analysis of the neck and wing tip follicle tissues of the 2 plumage colors, we demonstrated that within the interval, only 1 gene, SLC45A2 expressed significant differently (P < 0.05). Through KASP, we identified L347M and A10331272T in solute carrier family 45 member 2 (SLC45A2), and B2 haplotype of cyclin-dependent kinase inhibitor 2A (CDKN2A), showed near complete association with the phenotype. Eventually, we designed a hybridization experiment for verifying the locus of sub-Columbian plumage, which is inherited through Z-linked dominant inheritance and is controlled by SLC45A2 and CDKN2A.