Unique feather color characteristics and transcriptome analysis of hair follicles in Liancheng White ducks

Avian feather color is a fascinating trait, and the genetic mechanism of duck plumage formation is still in the preliminary stage. In this study, feather color of Liancheng White ducks was analyzed by determination of melanin content and RNA-seq analysis. In this research, 9 ducks from Mallards (n = 3), Liancheng White (n = 3) and Pekin ducks (n = 3) were used by high performance liquid chromatography (HPLC) and Masson-Fontana staining to reveal the difference of feather melanin content. RNA-seq from 11 hair follicle tissues (1- and 8-wk-old) of Liancheng White ducks (n = 5) and Pekin ducks (n = 7) was used to analyze the candidate genes for the feather melanin synthesis, and Immunofluorescence experiment was used to show the protein expression in 6 black- and white-feathered ducks. Pectorale, skin, liver, fat, brain, heart, kidney, lung, spleen of an 8-wk-old black-feathered Mallard were collected for candidate gene expression. The results showed that the contents of feathers, beak, web melanin in Liancheng White ducks were higher than in Pekin ducks (p < 0.05). Melanin within hair follicles was located in the barb ridge and hair matrix of black feather duck, also we found that TYRP1, TYR, SOX10 genes were differentially expressed between Liancheng White and Pekin ducks (p < 0.05), and these genes were mainly expressed showed in duck skin tissues. This study revealed the unique feather color phenotype of Liancheng White duck shedding light on the transcriptome that underlies it.