Genome-wide association study of economic traits and functional characterization of MAN2A2 in the Jilin White Goose

Egg-laying and growth traits play a critical role in determining the economic value of geese. This study integrates a genome-wide association study with functional analyses to elucidate the genetic basis of these traits in the Jilin White Goose. We systematically phenotyped 200 geese for key egg-laying traits, such as total egg number and average egg-laying interval, as well as growth traits, including body weight and tibia length. The GWAS, utilizing whole-genome resequencing, identified 766 significant single nucleotide polymorphisms. Notably, a non-synonymous mutation (chr19:361983:C:A) within the MAN2A2 gene was strongly associated with average egg-laying interval. Other significant loci included UBE2R2, which is associated with body weight, and NTN1/SLC2A9, linked to tibia length. Functional validation in goose follicular granulosa cells demonstrated that the knockdown of MAN2A2 activated the mitochondrial apoptosis pathway, as indicated by increased levels of Caspase-3 and an elevated BAX/Bcl-2 ratio, while suppressing CDK4, thereby promoting apoptosis and cell cycle arrest. In contrast, overexpression of MAN2A2 enhanced cell proliferation and exhibited anti-apoptotic effects. Additionally, silencing of MAN2A2 induced upregulation of MYC, suggesting its involvement in a complex stress-response network. These findings identify MAN2A2 as a key regulator of granulosa cell homeostasis, influencing both follicular development and the egg-laying interval. This study provides valuable genetic markers and insights for breeding improvements in Jilin White Goose.