Detection Of TGF-beta Access Key Genes InDel And Analysis Of Its Relationship With Growth Character In Four Sheep Breeds

With the continuous development and advancement of animal molecular breeding,modern molecular genetics,DNA analysis theories and technologies have greatly increased the possibility of direct genotyping and early selection and breeding at the level of DNA with much selection accuracy.InDel（insert/deletion）markers have a simple typing system,high stability,good polymorphism,and are widely used in animal and plant molecular breeding and population genetic analysis.TGF-β signaling pathway plays a very important role in the regulation of cell proliferation and differentiation,embryonic development,and skeletal formation.LTBP1,THBS1,SMAD4 are important members of the transforming growth factor-β signaling pathway.In this study,we studied Tong sheep（166）,Hu sheep（201）,Small Tail Han sheep（195）,and Lanzhou Fat Tail sheep（69）of 4 varieties of Chinese native sheep（631）.The effects of insertional deletion mutations of four genes（LTBP1,THBS1,SMAD4,PITX2）in TGF-beita signaling pathway and adjacent signaling pathways LHX3 on growth traits such as body length and body weight of sheep;aims to compare differences in growth traits of four sheep populations and to describe the correlation of genes such as LTBP1,THBS1,SMAD4 and growth traits in sheep TGF-β signaling pathway provides some data support for sheep molecular breeding.Research result indicates:1.For the three InDel loci of LTBP1 gene,9 haplotypes were found and the polymorphisms were abundant.For InDel-1（rs1089171651）,the DD genotype of was significantly higher in body length and cross height of the Lanzhou Fat Tail female sheep than those of the ID genotype（P<0.05）;For InDel-2（rs1085487085）,the ID genotype was significantly higher in chest circumference and cross height of the Lanzhou Fat Tail female sheep than those of the DD genotype（P<0.01）,while chest circumference of the Small Tail Han male sheep of the genotype II was significantly higher than those of the ID genotype and the DD genotype（P<0.01）;For InDel-3（rs1086780404）,body length of Small Tail Han sheep of ID genotype was significantly higher than that of the DD genotype（P <0.05）,while chest circumference and cross height of Lanzhou Fat Tail female sheep of the ID genotype was significantly higher than that of the II genotype（P <0.05）.2.For the two sites of the THBS1 gene,four haplotypes were found and the polymorphism was abundant.At the InDel-1 locus（rs1092852024）of the THBS1 gene,Hu sheep’s chest circumference of the genotype II was significantly higher than that of the DD genotype（P<0.01）,while body length of Small Tail Han sheep of the ID genotype was significantly higher than that of the II genotype（P<0.01）;At the InDel-2 locus（rs1094397979）of the THBS1 gene,chest circumference of Lanzhou Fat Tail male sheep of the ID genotype was significantly higher than that of the II genotype and the DD genotype（P<0.01）.3.Three genotypes were identified for the insertion/deletion sites（rs595529487）of the SMAD4 gene,and polymorphisms were abundant in the four sheep breeds.The body weight and cross height of the Lanzhou Fat Tail male sheep of the DD genotype was significantly higher than those of the ID genotype（P <0.05）,while chest width of Lanzhou Fat Tail female sheep and circumference of cannon bone of Hu sheep were significantly higher than those of the DD genotype（P <0.05）.4.No polymorphism was found in the LHX4 gene.A 29 bp InDel（NC₀19460: g.3107494-3107522）was found in the LHX3 gene.Polymorphism was abundant in the four sheep breeds.The chest width and the body length of Tong sheep of the DD genotype was significantly higher than those of ID genotype（P <0.05）,the body length of Small Tail Han female sheep of the II genotype was significantly higher in than that of ID genotype（P <0.05）,and the chest width of Small Tail Han sheep of the ID genotype was significantly higher than that of the II genotype and the DD genotype（P <0.05）.5.Two InDel sites（NC₀19463: g.14890658-1489066 & NC₀19463: g.14885723-14885734）were found in PITX2 gene.No DD type was found in all individuals.Four haplotypes were found in Hu sheep,Tong sheep and Small Tail Han sheep.There were only two single species in Lanzhou Fat Tail sheep.For PITX2 gene InDel-1 locus,ID genotype’s chest width of Tong female sheep and chest depth of Small Tail Han female sheep was significantly higher than those of the II genotype（P<0.01）;For PITX2 gene InDel-2 locus,ID genotype’s breast circumference of Hu sheep and body length of Tong female sheep was significantly higher than those of the II genotype（P<0.05）.The study of five key genes InDel in the TGF-β pathway showed that the 9 loci of LTBP1,THBS1,SMAD4,LHX3,and PITX2 were rich in InDel diversity,which can be used as DNA marker of chest circumference and cross height of the Lanzhou Fat Tail sheep,chest circumference and body slant length of the Small Tail Han sheep,body weight and breast circumference of Hu sheep,chest width and the body length of Tong sheep and other growth traits in sheep breeding selection.