Genetic effect of the follicle-stimulating hormone receptor gene on reproductive traits in Beijing You chickens.

We analyzed the effects of the polymorphisms of the follicle-stimulating hormone receptor (FSHR) gene on egg production in a Beijing You chicken population divergently selected for egg number, egg weight, and BW across 3 generations. The FSHR gene encodes the receptor of follicle-stimulating hormone, which controls follicular development and recruitment in the ovary. Seven SNP of the FSHR gene were investigated in 768 pedigreed hens from the G2 generation. Association analysis revealed that g.-310A > G, g.-181A > T, and g.159C > T were associated with egg number at different weeks of age (P < 0.05) and that g.75470A > G and g.75860G > A were associated with egg weight at first egg (P < 0.05). The favorable allele of g.-181A > T and g.159C > T had increased frequencies not only in the high line but also over the 2 generations (G2 vs. G1) within the high line. To confirm the association study, we tested for FHSR mRNA expression level in the chicken ovaries. The results showed that the homozygous favorable genotypes of g.-181A > T and g.-310A > C increased the FSHR mRNA expression level compared with the other genotypes (P = 0.001 and P = 0.026, respectively). Hence, our findings implied that the SNP g.-181A > T could be a potential genetic marker for egg performance in the Beijing You chicken, but further replications of our study in other chicken populations are needed to verify such effects detected here.