<scp>RNA</scp> sequencing analysis reveals key genes and pathways associated with feather pigmentation in mule ducks

Feather color is an important morphological trait of poultry. At present, the reports on the inheritance of plumage color of mule ducks at the molecular level are few, and the regulatory mechanism in white plumage rates of different mule ducks remains unclear. This study aimed to broaden the understanding of the white plumage rates in mule ducks to improve their production value. We used RNA sequencing to analyze and compare the mRNA expression profiles in hair follicle tissues from 10-week-old mule ducks with black and white plumages, thereby revealing the temporal gene expression patterns and pathways associated with plumage color regulation. In total, 1672 annotated differentially expressed genes (DEGs) were identified in black and white plumages from different databases between mule ducks with the 2 plumage colors. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment in hair follicle tissues indicated that the aforementioned DEGs were mainly involved in the melanin signaling pathway. Concurrently, we use weighted gene co-expression network analysis to detect core modules and hub genes associated with melanin biosynthesis in feathers. The green module exhibited the strongest correlation with the phenotypic traits, encompassing a total of 1049 genes. Subsequent Kyoto Encyclopedia of Genes and Genomes enrichment analysis identified 11 genes as pivotal in the melanin biosynthetic pathway, including EDRNB2, TYR, KIT, EDNRB, and MC1R. The differential expression of eight selected DEGs was verified using quantitative reverse transcription-PCR, and the results were consistent with RNA-seq data. This study provides a basis for understanding the differences in plumage color development in mule ducks.