Tissues Expression Analysis, Novel SNPs Of The Bovine Angptl3Gene And Its Effects On Growth Trait

Angiopoietin-like protein3（angptl3） is a secreted protein that regulates lipid, glucose andenergy metabolism. Herein, the gene expression profile was detected in various tissues inJiaxian red cattle by quantitative real-time PCR. While the polymorphism of the Angptl3genewere analyzed by DNA pools sequencing, PCR-RFLP and PCR-SSCP method in Jiaxian redcattle, Nanyang cattle, Luxi cattle, Bohai black cattle, Qinchuan cattle and Gaoyuan yak, atotal number of424, and investigated their associations with growth traits. To assess whetherAngptl3gene could be efficient molecular markers for marker-assisted selection （MAS）, theassociations between these SNPs or their combinations with growth traits were evaluated incattle, which will provide some genetic information for the efficient selection program incattle breeding. The results were as follows:1.Tissue expression profile of Angptl3gene in Jiaxian red cattleThe mRNA expressions profile showed that Angptl3gene was predominantly expressedin liver in Jiaxian red cattle, with minor expression in spleen and lung. Other tissues （liver,kidney, rumen, skeletal muscle, adipose, testis） was not expressed.2. The genetic polymorphism of bovine Angptl3geneAll of the exons of Angptl3gene were detected in six populations, and three SNPs werediscovered: g.104A>T, g.509A> G and g.8661T> C （GenBank:NC₀07301）. Threemutations were located in CDS region, belonging to missense mutations thant introducedamino acid changes. One SNP （g.104A> T） resulted in amino acid substitution that is Iie/Phe, g.509A> G locus changes amino acid, Gln to Arg and g.8661T> C locus resulted toSer/Pro. The g.104A> T and g.509A> G loci were low polymorphism in Qinchuan cattlepopulation and moderate polymorphism in Bohai black cattle and Luxi cattle, while g.8661T> C locus were low polymorphism in for the four populations （Jiaxian red cattle, Luxi cattle,Nanyang cattle and Bohai black cattle）.Through linkage disequilibrium analysis, the results showed that g.104A> T and g.509A> G loci were in strong linkage disequilibrium in five yellow cattle （r2>0.33）, while g.104 A> T and g.8661T> C loci, g.509A> G and g.8661T> C loci were linked weakly （r2<0.33）, respectively.3. The association analysis between the genetic polymorphism of bovine Angptl3gene and thegrowth traitsAssociation between single locus and growth traits revealed that AT genotype hadgreater body height, body length than TT genotype at g.104A> T locus （P <0.05） in Luxicattle. At g.509A> G locus, AG genotype had greater body length than GG genotype inLuxi cattle （P <0.05）, GG genotype had greater chest circumference than AA genotype inJiaxian red cattle. When combined the three SNPs （g.104A> T locus, g.509A> G locusand g.8661T> C locus）, association analysis showed that ATAATT combined genotypehad greater body height, body length, chest circumference, hip width than AAAATTgenotype （P <0.05）.