Goose FMO3 gene cloning, tissue expression profiling, polymorphism detection and association analysis with trimethylamine level in the egg yolk

Flavin-containing monooxygenase 3 (FMO3) plays a critical role in catalyzing the conversion of trimethylamine (TMA) to trimethylamine-N-oxide (TMAO) in vivo. Despite the well-documented association between FMO3 mutations and a 'fishy' off-flavor eggs in chicken and quail, little information is available regarding the molecular characteristic of goose (Anser cygnoides) FMO3 and its relationship with the yolk TMA content. To fill these gaps, we cloned the full-length cDNA sequence of goose FMO3, which comprised 1851bp encoding 531 amino acids. FMO3 mRNA was dramatically expressed in liver than in other tissues in the geese. Eight single nucleotide polymorphisms (SNPs) were detected in the entire coding region. The CC genotype at the T669C site, GG at the A723G site, and AA at the G734A site of FMO3 were highly significantly associated with elevated TMA content in goose egg yolk (P