Analysis Of Candidate Functional Mutations Of IGF1R?RasGRP1 And InsR Genes In Pigs

As the biggest country raising pigs,pork products accounted for about 65% of China's meat consumption.Pig industry is the emphasis of the development of animal husbandry in China,but Chinese economic benefits of pigs have yet to be improved.There has a large gap between Chinese native pigs and Western pigs in the economic traits.The economic performance of Western pigs has been constantly improved due to long-term artificial selection.Because of the different objectives and the weak selection,Chinese native pigs have a large gap with Western pigs in some important economic traits,such as growth rate and lean meat percentage.The great difference between Chinese native pigs and Western pigs in the economic traits is caused by different artificial selection.In this study,we firstly used high-throughput sequencing data to analyze the differences of the selection signals between Chinese and Western pigs,and screened out the genes that were strongly selected in Chinese and Western pigs.It was found that IGF1 R,Ras GRP1 and Ins R genes were strongly selected in Chinese and Western pigs.We then carried out the alleles differential expression study and analyzed the conservation of the sites in order to predict the key functional control sites and carry out the follow-up research in molecular level and population level.The purpose of this study is to find the key molecular markers for the improvement of pigs.The main results of this study are as follows:(1)It was found that IGF1 R,Ras GRP1 and Ins R genes were strongly selected in Chinese and Western pigs through selection signal analysis,and there were three candidate functional sites probably affecting gene expression through alleles differential expression study and species conservation analysis.(2)Electrophoretic mobility shift assay showed that transcription factor YY1 could bind to IGF1 R gene-61 K A/G polymorphism and had stronger binding ability to allele G.Dual-luciferase reporter assay system showed that this site could promote the downstream gene expression,and G allele play a stronger role.We also found that the decreased expression of transcription factor YY1 could inhibit the expression of IGF1 R by RNA interference assay.(3)Electrophoretic mobility shift assay showed that the transcription factor Myo D could bind to the IGF1 R gene Intron20 G/A polymorphism and had stronger binding ability to allele G.Then we found that the expression of IGF1 R and Myo D were both significantly increased in mouse skeletal muscle satellite cells by quantitative PCR.(4)Association analysis of IGF1R gene-61 K A/G polymorphism with the immune and growth traits of Duroc×Er Hualian F2 pigs showed that the site was significantly correlated with eosinophil percentage in 33-day-old pigs(P<0.01),and was correlated with the weight of 80-day-old pigs(P<0.05),indicating that the site could be used as a candidate molecular marker for the improvement of pig growth and immune traits.(5)Association analysis of IGF1R gene Intron20 G/A polymorphism with the immune and growth traits of Duroc×Er Hualian F2 pigs showed that the site was correlated with eosinophil percentage in 33-day-old pigs and the weight of 80-day-old pigs(P<0.05),indicating that the site could be used as a candidate molecular marker for the improvement of pig growth and immune traits.(6)Association analysis of RasGRP1 gene +1K A/G polymorphism with the immune and growth traits of Duroc×Er Hualian F2 pigs showed that the site was correlated with the weight of 80-day-old pigs(P<0.05),indicating that the site could be used as a candidate molecular marker for the improvement of pig growth traits.