Analysis Of The Exon10of Growth Hormone Receptor Gene In Several Domestic Chicken

In this study, the exon10of Growth Hormone Receptor (GHR) gene in2improved breeds containing Roman layer and AA broiler chicken, and4indigenous chicken in Sichuan provience(Tibetan chicken, Jiuyuan black chicken, Junlian white feathers black bone chicken and mountain black bone chicken) were obtained by sequencing PCR products directly, screening for Single Nucleotide Polymorphism(SNP) and genetic diversity analysis were conducted to discuss the effect of GHR gene mutation on the growth and development traits from chicken in different breeding degrees, and then provide a effective molecular evaluation and molecular marker on breeding value for the directional cultivating direction of this four native chicken and a scientific basis of preservation and utilization for local chicken.We obtained1160bp of the GHR coding region spanning the complete exon10which encoding320amino acid165individuals of six breeds. Through bioinformatics analysis, we found the content of A+T in the obtained sequence was57.41%, the content G+C was42.58%, the content of A+T is much higher than that of G+C.After compared with the published SNPs form Gene Bank, five innovational single nucleotide polymorphisms (SNPs) was screened in all individuals, that is g.12987435G>A、g.12987707G>A、g.12987721G>T、g.12987990A>T、g.12988071G>A,(the location of this five SNPs in genome are g.12987435,g.12987707,g.12987721,g.12987990�'�g.12988071) three SNPs (g.12987435G>A,g.12987990A>T, g.12988071G>A) of them were synonymous mutation, the rest two mutant (g.12987707G>A、g.12987721G>T) were missense mutations. Only the mutant g.12987990A>T was found in Roman layer and AA broiler, but this mutant also exist in the other four breeds. meanwhile the mutational sites are variety in four indigenous chickens, the all five mutations exist in Jiuyuan black chicken and Junlian white feathers black bone chicken, the mountain black bone chicken contained all this mutations except the SNP g.12987721G>T, and Tibetan chicken have three SNPs g.12987435G>A, g.12987990A>T�'�g.12988071G>A. Besides, the PIC value of A A broiler. Roman layer and4local chicken are GG/GG/0.386, GG/GG/0.340, GG/GG/0.056,0.490/0.374/0.577, GG/GG/0.493respectively. After analysis by Phase software, six haplotype was found, and the haplotype H1(G-G-G-A-G) and H2(G-G-G-T-G) are both advantage, the haplotype combination H1H1,H1H2and H2H2are preponderant. The chi-square test results showed that the five mutations in different haplotypes and local chicken have reached highly significant level, indicating that the variety of GHR gene can reflect the breeding digree and could be treated as a reference genetic maker for assessment of breeding value in indigenous chickens.