Study On The Correlation Between The Single-stranded Nucleotide Polymorphisms Of Follicle-stimulating Hormone β And Laying Performance In Wenchang Chicken

To study the mechanism of egg production from the perspective of molecular genetics, isnot only useful to accelerate the cultivation of the varieties and strains of the high layers, to bethe significance of the protection, development and utilization of local chicken breeds inChina and, but also the study has important the guiding significance in chicken genetics andendocrinology. Wenchang chickens is the precious wealth of resources in the gene pool ofspecies of poultry in China, which has the local varieties typical characteristics through themasses of long-term breeding in Hainan’s tropical and subtropical specific naturalenvironment(Geng Zhaoyu et al,2003). Long light stimulates chicken gonadal development,and promote sexual maturation in the chicken through the optic nerve. Long natural sunshinein Hainan leads to earlier precocious puberty of Wenchang chickens, and egg production rateof hen is5%at127d.Follicle-stimulating hormone(Follicle-stimulating hormone, FSH) is secreted by theanterior pituitary glycoprotein gonadotropins, and plays an important role in thehypothalamus-pituitary-gonadal reproductive axis, which is composed of two subunits, thecommon α-subunit of hCG, LH, TSH, and other glycoprotein hormones and the specific β-subunit, which determines the binding to specific receptors and induction of biologicalresponse, and it plays a key role in hypothalamic-pituitary-gonad axis.The purpose of this study was to detect single nucleotide polymorphisms (SNPs) ofexons2and3and1,2intron within FSHβ gene, to analyze the genetic structure, and toinvestigate the effects of the gene on egg laying performance of Wenchang chickens. Basedon the chichen DNA sequences of exons2and3and1,2intron within FSHβ gene inGenBank, three primer pairs for FSHβ gene, respectively, were designed to screen onenucleotide variation of intron1by means of PCR-SSCP protocol and analyze the associationof polymorphisms with early egg reproduction. The main results are as shown as following:The amplified fragment within one pairs of three primers showed polymorphism, and thepoint mutations of amplified sequence in intron1of FSHβ gene.Based on the sequence of Wenchang Chickens FSHβ gene introns1，specific amplification sequence were designed and PCR-SSCP analysis was conducted under differentelectrophoretic conditions. The results were that the primer sequence was polymorphism, andget the two genotypes AA and AB. SNP polymorphisms (SNPs) was got by sequencing, andA→C mutation occurred in914of intron1.The statistical analysis of egg production traits and SNP polymorphism of FSHβ geneintrons1in Wenchang Chickens showed that SNPs in FSHβ gene introns1did not influenceegg production traits including GDP egg volume, egg production of18-21weeks of age(NE-(18-21)W) and35-39weeks of age (NE-(35-39)W), the number of abnormal eggs, andage at first egg(p>0.05). However, egg production of the AA genotype was significantly (P<0.05) more than that of the AB genotype in the latter, that is,22-34weeks of age.Thevarious genotype did not influence body weight of18-39weeksTwo alleles were got in the P1primer of Wenchang Chickens by amplified, and thefrequency of genotype AA and AB were0.49and0.51, respectively. The frequency of thetwo alleles A and B were0.74and0.26. Chi-square fit test shows that the intron1region ofWenchang Chickens remained at the Hardy-Weinberg equilibrium (P>0.05).