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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.

In dairy cattle, 4 important recessive hereditary diseases exist: complex vertebral malformation (CVM), bovine leukocyte adhesion deficiency (BLAD), citrullinemia (CTLN), and deficiency of uridine monophosphate synthase (DUMPS). Holstein Associations in developed countries have established monitoring systems for such disorders in Holstein bulls for decades. Over the past decades, China has continuously imported Holstein semen and embryos, mainly from North America but also from Europe. The dissemination of such genetic defects was undetermined until now, although efforts were taken to develop molecular techniques and detect carriers for CVM and BLAD in small populations of Chinese dairy cattle. Thus, herein we extensively screened 732 proven bulls participating in artificial insemination programs and 136 young bulls entering progeny test from 15 bull stations in China for CVM, BLAD, CTLN, and DUMPS. The proportion of carriers of the defects was found to be 7.72, 1.38, 0.23, and 0.12%, respectively. Given our findings, early diagnostic and monitoring systems on recessive inherited disorders among proven and young bulls entering the national genetic improvement programs for dairy cattle of China should be established immediately, in which a series of measures will be taken to prevent further spreading of such disorders and gradually eliminate them in the dairy cattle population in China.

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