| Ghrelin is a novel endogenous ligand for growth hormone secretagogues receptor (GHS-R) and it is expressed primarily in the stomach and hypothalamus both in mammals and poultry, and is likely to accelerate the secretion of growth hormone and uptake of food. This study were to research the polymorphism of Ghrelin gene, and associations between Ghrelin polymorphic loci and body weight, five body measurement traits(body length, fossil bone length, breast width, shank length, and shank circumference ) and eight carcass traits (carcass weight, semi-eviscerated weight, eviscerated weight, breast muscle weight, thigh weight, heart weight, liver weight, spleen weight) in Jinghai Yellow chicken. The results were as follows:(1) Three pairs of primers P1, P3 and P5 from seven primers designed were polymorphous based on the sequence of chicken's Ghrelin gene (GenBank No. AY303688). Six genotypes (AA,BB,CC,AB,BC,AC) were detected by polyacrylamide gel electrophoresis in PCR products of primer P1, three genotypes DD, DE and EE of primer P3, and two genotypes (FF,FG) of primer P5, genotype GG was not checked.(2) Sequencing results indicated that there are a 2bp deletions (TC) at the site of 73 bp (BB genotype) and has a 8 bp deletion (CTAACCTG) at the site of 79 bp (CC genotype) for primer P1. Single nucleotide loci mutations were C→T at 546 bp site for P3. For P5, mutations were T→C at 1274 bp site. (3) The gene frequency of allele A, B and C was 0.362, 0.482 and 0.156 in P1 respectively, and that of allele D and E was 0.808 and 0.192 in P3 respectively. The two SNP loci were in Hardy-Weinberg Equilibrium. The gene frequency of allele F and G was 0.965and 0.035 in P5 respectively.(4) Through least square analysis, the results showed that the genotypes of primer P1 had highly significant effect or significant effect on body weight at 1st day, 1nd week ,breast width ,shank length and heart weight(P<0.05 or P<0.01), and that the 8bp and 2bp deletions were significantly associated with several traits after all which indicated that this site might be used to MAS as molecular markers.(5) The genotypes of primer P3 had highly significant effect or significant effect on liver weight and leg muscle weight (P<0.05 or P<0.01). Through Multiple comparison, results showed that the liver weight of genotype DD was higher than that of DE, and leg muscle weight of genotype DE as higher than that of DD in Jinghai yellow chicken population, So the mutation site had important significance to the selection of visceral and leg muscle in Jinghai yellow chicken population.(6) The genotypes of primer P5 had closer correlation with production performance. Body weight from the he 1st day to16th weeks of genotype FG was higher than that of FF in Jinghai yellow chicken population, and at some weeks the difference was significant between genotype FG and FF (P<0.05). Carcass traits of genotype FG were better than that of FF in the mass. For the body measurement traits, cocks'shank length of genotype FG was bigger than that of FF (P<0.05). Correlated traits of heterozygote was better than that of homozygote in a word.
|
PDF Full Text Request