Single Nucleotide Polymorphisms In Chicken FSHβ Gene And Association With Early Egg Production

Follicle-stimulating hormone (FSH) is a pituitary glycoprotein gonadotropin that is composed of two subunits, the commonα-subunit and the specificβ- subunit, which determines the binding to specific receptors and induction of biological response, and it plays a key role in hypothalarnic-pituitary-gonad axis. Considering the association of FSHP with chicken reproductivity, the FSHP gene was selected as a candidate to screen the nucleotide variation by means of PCR-SSCP protocol and analyze the association of polymorphisms with early egg reproduction.The WenChang (WC) chickens (n=150), a Chinese local breed, and Babcock (n=100) were used to detect SNPs in the FSHβsubunit gene by PCR-SSCP. Eleven primers were designed based on the sequence of chicken FSHβgene (GenBank accession no. AF467082) to obtain DNA fragments covering the 5'promotor and all exons of FSHβby PCR. The SSCP detection of PCR products showed that 2 sites, pro2 and exon3c, were polymorphismic in the population. x~2 test suggested that the population were in the state of Hardy-Weinberg equilibrium at the two sites. Two polymorphismic sequences were cloned sequenced to detect the SNPs. Three SNPs, T2414C, A2447G and A2540C, were identified in exon3, which did not led to amino acid variation in the 3'-untranslated region. Six nucleotide variation at G-494 A, T-470A, A-464 G, -450A insertion, A-405G and A-361G, were identified in promotor region. Association analysis of early egg production traits and FSHβgene polymorphisms in WC chicken showed that SNPs in exon3 did not influence egg production traits including age at first egg, weight of first egg, egg weight at 40 weeks, and egg number at 40 weeks(.P>0.05). In pro2 site, the age at first egg of genotype BB were earlier (P<0.05) than that of AA and AB, and the egg number at 40 weeks of genotype BB were higher (P<0.05) than that of AA and AB. The facts indicated that alleles B was the favorable gene for early egg production traits. In Babcock, an egg-type chicken, the frequencies of allele A and B in pro2 site were 0.29 and 0.71, respectively.Which supported, to some degree, the association.The putative binding transcriptional proteins of 5' -flank region were predicted using TFSEARCH ver1.3 on line. The result revealed that T-470A, A-464 G and A-361G lead to-changes of transcription factor. SNP of A-464G led to the absence of regulation factors, oct-1 and CdxA. A-361G caused a new binding site for GATA-1.