Transcriptome Analysis of Sexual Dimorphism in Dorsal Down Coloration in Goslings

Abstract

Background Distinctive sexual dimorphism in dorsal down coloration is apparent in day-old Hungarian white goose goslings, characterized by darker dorsal plumage in females and lighter plumage in males. The ability to autosex day-old goslings based on their dorsal down coloration is crucial for efficient management and nutrition strategies in the poultry industry. The objective of this research was to gain a deeper understanding of the potential biological and genetic mechanisms governing sexually dimorphic down coloration in geese, utilizing tissue slice analysis, biochemical assays, transcriptomic profiling, and q-PCR analysis. Results The tissue slice and biochemical results revealed that female geese exhibited a higher density of melanin-containing feather follicles and a greater concentration of melanin within these follicles compared to male geese during embryonic development at 17 days and in day-old goslings. Both female and male individuals, in comparison to 17-day goose embryos, showed a significant decrease in melanin concentrations in the dorsal skin of day-old goslings. Through transcriptome analysis, we identified a set of differentially expressed genes (DEGs) (MC1R, TYR, TYRP1, DCT and MITF) associated with Melanogenesis pathways that exhibit substantial down-regulation or complete silencing specifically within the dorsal skin of day-old goslings when compared to 17-day embryos. This resulting in impaired melanin synthesis in the feather follicle. Additionally, sexual dimorphism in feather coloration is associated with two key DEGs (MC1R and MITF). Female geese exhibited higher expression levels of MC1R and MITF, positively correlated with increased melanin synthesis and deposition, resulting in a more pronounced plumage phenotype characterized by darker coloration. Conclusions Melanin synthesis in goose feather follicles was determined by the expression of multiple melanogenesis genes. Sexual dimorphism in dorsal down coloration of day-old Hungarian white goose goslings was contingent upon two essential MC1R and MITF genes. Our research lays the essential foundation for advancing the breeding in autosexing geese, promising substantial benefits to breeders and producers.