| GH-IGFs growth axis is an important endocrine metabolism axis in the animal body,which plays a key regulatory role in the growth and development of animals.It is composed of a variety of regulatory hormones,receptors,binding proteins and proteases.The level of hormone secretion on the GH-IGFs axis is related to the percentage of body fat and visceral fat,muscle mass,immune function,and the concentration of estrogen and androgen.Mutations in genes often lead to changes in gene expression levels,and transposon is a DNA sequence that can move in the genome by itself.In mammalian genomes,transposons account for 30%-50%of the genome,and are mainly retrotransposons,and retrotransposons usually contain enhancers,promoters and other regulatory elements,which play a role in gene expression Important regulatory role,and new molecular markers based on transposon insertion polymorphisms have become an important tool for studying biological genome evolution,biodiversity,and molecular breeding.In this study,we used bioinformatics methods to excavate the structural variation caused by retrotransposons in some key genes on the growth axis of pig GH-IGFs,and then verified by PCR,obtain retrotransposon insertion polymorphic sites in some key genes on the growth axis of GH-IGFs;Detect its distribution in small groups of different pigs and carry out population genetic analysis on them,then two RIPs,GHR-RIP10 and GHR-RIP8,were selected for genotyping in a large population of large white pigs and then analyzed for their correlation with related production performance.Also,functional exploration of the SINE inserts at the GHR-RIP10 site,First.detect the difference in GHR gene expression of individuals with different genotypes at this locus.Furthermore,the insertion and deletion of two fragments of SINE at the cloning site were performed,and the effect of SINE at this site on the GHR gene promoter was detected at the cell level.The results obtained in this paper are as follows:1.A total of 59 predicted RIPs were identified through sequence alignment and transposon annotation in 8 genes(GH,GHR,IGF1,IGF1R,IGF2R,IGF2BP1,IGF2BP2,IGF2BP3)in the growth axis of GH-IGFs.It was further confirmed by PCR to obtain 10 definite RIPs,which are located on five genes(GHR,IGF1,IGF2R,IGF2BP2,IGF2BP3)and they are all distributed in the intron regions with weak gene conservation,and half of the RIPs are transposons from SINE cause.2.After PCR detection of 6 RIPs in GHR and IGF1 genes in 7 varieties,4 out of 6 RIPs loci were polymorphic in all 7 varieties,and half of the 6 RIPs in the tested population are in line with Hardy-Weinberg equilibrium.The correlation analysis of GHR-RIP8 and GHR-RIP10 in the large white pig population(n=711)shows that,The correlation analysis of GHR-RIP8 and GHR-RIP10 in the large white pig population(n=711)showed that there was a very significant difference between GHR-RIP8 homozygous insertion compared to GHR-RIP8 heterozygous insertion,GHR-RIPS homozygous non-insertion age at 100 kg body weight were significantly different(P<0.05);GHR-RIP10 homozygous with insertion and GHR-RIP10 homozygous without insertion had a significant difference in corrected backfat thickness(P<0.05).3.It was confirmed by the RT-PCR experiment that the GHR gene expression level in the liver,kidney,and fat of the 1-month-old Sujiang pigs with different genotypes(SINE+/+and SINE+/-)produced at the GHR-RIP10 locus was much higher than the Expression level in muscle.SINE+/+ individuals have significantly lower expression levels in muscle tissue than SINE+/-individuals(P<0.05),and SINE+/+individuals have lower expression levels in liver tissue and kidney than SINE+/-individuals,and expression in adipose tissue has the opposite result. |
