Polymorphism And Bioinformatics Analysis Of MC4R、MRF4、PROP1Gene In Sheep

This experiment used the PCR-SSCP technology to find mutation of the MC4R gene, MRF4gene and PROP1of Yongchang meat sheep new breeding population, small tail Han sheep andHu sheep，and used NCBI and ExPaSy，which are the online tools about the biologicalinformation analysis, to find the amino acid sequence of each gene and the Physicochemicalproperties, structure and function of each sequence, to labeled sheep growth traits as assistantselection and lay the theoretical foundation for molecular breeding. The results are as follows:1. This experiment detected4polymorphic loci in3segments of MC4R gene, respectivelyis: C495T, G511A, C732G, G896C, the C495T and G896C are nonsense mutations, encoding Serand Ala respectively; The G896C locus，there2genotypes in the3breeds of sheep，CC and CD。The3sheep breeds were in low polymorphism and Hardy-Weinberg equilibrium in the site, therewas no significant difference between them;C732G belongs to a kind of inter mutation, small tailHan sheep is G bp, encoding Met, the other two varieties are C nucleotides, encoding Ile. Theprotein second structure prediction shows that, the different amino acid sites, lead to the secondstructure of the genes encode proteins are slightly different, the original composed of51.5%alpha helix,16.27%beta sheet and32.23%random coil, but changed to51.2%alpha helix,15.36%beta sheet and33.43%random coil. The G511A site in the amino acid changes from Gluto Lys, leading to the second level structure of the genes encode proteins are slightly different,varying to51.5%alpha helix,14.46%beta sheet and34.04%random coil. At the G511A site,G511A together with C495T in the three sheep breeds are reflected, showed3genotypes: AA, ABand BB, and no significant difference between the3varieties, the dominant gene is B, BB is thedominant genotype. In these3genotypes, small tail Han sheep in moderate polymorphism, theother two varieties were low polymorphism, except for Hu sheep, the rest of the two species arein the Hardy-Weinberg equilibrium;The amino acid sequence of MC4R has hydrophobic regionsignificantly,7transmembrane helical regions and signal peptide. The main elements in thesecond structure of the MC4R encoded protein are the alpha helix and random coil. By homologyanalysis, this experiment found that the similarity of MC4R gene in sheep and goats, cattle, pig,human and gorilla is respectively97%,94%,81%,83%and83%. 2. This experiment did not detect the fragment has polymorphism in the exon1ofPROP1.The overall performance of the PROP1amino acid sequence is hydrophilic. This proteinthe protein belongs to the membrane protein and contains12phosphorylation sites. The maincomponents of its second level structure are the alpha helix and random coil. This experimentfound that the similarity of PROP1gene in sheep and boars, dogs, genes in human and gorilla isrespectively95%,78%,80%,75%and77%.3. The overall performance of the MRF4amino acid sequence is hydrophilic. Blasting theresults of sequencing with sequence alignment in NCBI, appeared the different between T and Cin162, codon ATC and ACC, encoding amino acids were Thr and Ile, lead to the second structureof the genes encode proteins are slightly different. This protein the protein belongs to themembrane protein and contains22phosphorylation sites. The main components of its secondlevel structure are the alpha helix and random coil. This experiment found that the similarity ofMRF4gene in sheep and goats, cattle, pig, human and rat is respectively99%,99%,94%,97%and89%. Thus, the coding region of MRF4gene is very conservative.