Study On Polymorphism Of Chickens HMGCR Gene And Its Association With Resource Poulation Traits

The3-hydroxy-3-methylglutaryl coenzyme A reductase （HMGCR） is therate-limiting enzyme at the metabolism of cholesterol, and it Plays an imPortant rolein the Pathway of endogenous cholesterol biosynthesis. In this study, HMGCR wastaken as a candidate, and DNA sequencing technology, PCR amPlification,PCR-RFLP and the Created Restriction Site PCR-RFLP （CRS-PCR-RFLP） methodwere used to detect genetic variation in the F₂resource PoPulation of Gushi chickenand Anka broilers and silkies, and the assoiation analysis of the PolyPhorisms in thegenes with the economic traits and was Performed using the least-squares analysis.The main results are as follows:1. In the F₂resource PoPulation of Gushi chicken and Anka broilers, the threeSNPs were detected in the chicken3-hydroxy-3-methylglutaryl coenzyme A reductasegene. In this study, HMGCR PolymorPhisms of A5816T was located in intron9, andG12217T causing an amino acid change from Glutamine （Gln） to Histidine（His）, andg.12684T>C, causing a Proline （Pro） synonymous mutation, were found in exon17and exon18, resPectively.By PCR-RFLP method, the SCa I restriction enzyme is used in the A5816Tmutation; and a mismatch site in each of the downstream of the two Pairs of Primerswas introduced in order to create a Hinf I restriction site and an Eco88I restriction sitein PCR Products from the HMGCR gene of chickens. PoPulation genetics is analyzedand showed that A5816T（0.3707）、G12217T（0.3512） and T12684C（0.3635） aremoderate PolymorPhism loci （0.25⁰.50）. The three sites of heterozygosis are0.4915、0.4546、0.4774, and are close to0.5. Therefore, these three sites can be usedfor further genetic selection.2. In this study, for A5816T, genotyPes had significant associations with bodyweight（BW）, body weight12（BW12）, breast bone length12（BBL）, chest dePth8（CD8）, leg shear force（LSF）, breast shear force（BSF）, diameter of leg musclefiber（DiMF）, alkaline PhosPhatase（AKP）, low density LiPoProtein（LDL）, LacticDehydrogenase（LDH）（P<0.1）. For g.12217G>T, genotyPes had significantassociations with carcass weight （CW）, semi-evisceration weight （SEW）, eviscerationweight （EW）, head weight （HW）, claw weight （CW）, heart weight （HW）, sPleenweight （SW）, leg weight （LW）, leg muscle weight （LMW）, claw weigh rate （CWR）, double Pinion weight rate（DPR）, caecum length（CL）, body weight2（BW2）, bodyweight4（BW4）, body weight6（BW6）, body weight8（BW8）, body weight10（BW10）,body weight12（BW12）, shank length12（SL12）, Shank girth12（SG12）, Pelvisbreadth8（PB8）, Pelvis breadth12（PB12）, body slanting length4（BSL4）, body slantinglength8（BSL8）, body slanting length12（BSL12）, breast bone length4（BBL4）, breastbone length8（BBL8）, breast bone length12（BBL12）, density of leg muscle fiber（DLM）, diameter of leg muscle fiber（DiLM）, region of breast muscle fiber（RBM）,diameter of breast muscle fiber（DiBM）, alkaline PhosPhatase（AKP）, lacticdehydrogenase（LDH）, total Protein（TP）, low density liPoProtein（LDL）（P<0.1）.Different genotyPes in mutation of T12684C had a significant influence onsemi-evisceration weight （SEW）, heart weight （HW）, leg muscle weight （LMW）,Pancreas weight rate （PWR）, jejunum length （JL）, ileum length （IL）, caecum length（CL）, body weight2（BW2）, body weight4（BW4）, body weight6（BW6）, bodyweight8（BW8）, body weight12（BW12）, shank length8（SL8）, shank girth4（SG4）,shank girth8（SG8）, shank girth12（SG12）, body slanting length4（BSL4）, body slanting length12（BSL12）, breast bonelength12（BBL12）, abdominal fat rate（AFR）, density of leg muscle fiber（DLM）,asPartate aminotransferase（AST）, total Protein（TP）, Albumin（ALB）, Globulin（GLO）,Cholinesterase（CHE）, glycerin trilaurate（TG）, lactic dehydrogenase（LDH）（P<0.1）.3. The G12217T and T12684C of the3-hydroxy-3-methylglutaryl coenzyme Areductase gene were validated in Silky Chicken, and PoPulation genetics is analyzedand showed that G12217T（0.374） and T12684C（0.373） are moderate PolymorPhismloci （0.25⁰.50）. The two sites of heterozygosis are0.499、0.504, and are close to0.5.Therefore, these two sites can be used for further genetic selection.4. The correlation between two restriction sites PolymorPhism and silky eggquality and egg cholesterol content were analyzed, and the result showed thatG12217T mutation egg cholesterol content （P<0.1）; and the three genotyPes ofT12684C had significant influence on yolk weight correlation （P<0.1）.