Polymorphisms Of Chicken Estrogen Receptor Beta Gene And Its Association With Egg Production Traits

A large number of studies have shown that the estrogen is confirmed to be critical for the onset and maintenance of egg production in poultry. Through specific binding to its receptor it was also involved in the regulation of a series of physical activity during chicken laying process. Candidate genes was studied for the association analysis between the SNPs of estrogen receptor P gene and egg production traits.Eight pairs of primers were used to amplify parts of exons and 3'flanking nucleotide sequences of ESRβgene. Sequencing results revealed four nucletide mutations in ESRβ, SNP1 (C55567121T in exon 3 which is a synonymous mutation),SNP2(G55577770A in 5'flanking region), SNP3 (T55548086C in exon 1 which is a synonymous mutation) and SNP4 (C55577728T in 3'flanking region).The 3 SNPs distribution in five local breeders are great significant differences.The polymorphism information content(PIC) of the 3 loci in different breeds showed moderate and low polymorphism.Association analysis between three SNPs with egg production traits about the fourth generation of Partridge shank chicken show that SNP1 was significantly associated with the age at first egg(AF) (P<0.05).Compared AA genotype and AB genotype with BB genotype,the average AF were 8.09 days and 5.96 days later. SNP2 was significantly associated with the laying number of qualified hatching eggs on 40w(P<0.05)and AF(P<0.05).Compared CC genotype and CD genotype with DD genotype,The average numbers of qualified hatching eggs were 22.08 and 10.64 more than that of DD genotype. The average AF were 7.81 days and 4.97 days earlier than that of DD genotype.SNP3 has no significantly effect on egg production traits.Association analysis between three SNPs with egg production traits about the fifth generation of Partridge shank chicken show that SNP1 was significantly associated with AF(P<0.05).Compared AA genotype and AB genotype with BB genotype,the average AF were 5.35 days and 3.89 days later. SNP2 was great significantly associated with the laying number of qualified hatching eggs on 40w(P<0.01)and AF(P<0.01).Compared CC genotype and CD genotype with DD genotype,The average numbers of qualified hatching eggs were 26.05 and 14.36 more than that of DD genotype.the average AF were 9.54 days and 5.67 days earlier than that of DD genotype.SNP3 has no significantly effect on egg production traits.Compare with the association analysis between three SNPs and egg production traits of the two generations of Partridge shank chicken show that SNP1 was significantly associated with AF(P<0.05).SNP2 has significant or great significant related to the laying number of qualified hatching eggs on 40 weeks and AF. SNP3 has no significantly effect on egg production traits.Association analysis between egg production traits and the haplotype assemble constructed with the 3 SNPs show that the haplotype of H5(B-C-E) is propitious to the laying number of qualified hatching eggs on 40 weeks and the average egg weight at 40 weeks old(EW). The haplotype of H3(A-D-E) is not conducive to the laying number of qualified hatching eggs on 40 weeks while the haplotype of H2(A-D-F)is not conducive to EW.The association analysis between the variants and egg production traits show that the SNPs of ESRβgene have significant or great significant related to AF and the laying number of qualified hatching eggs on 40 weeks.But there is no. relation with EW.