ASSOCIATION OF SINGLE NUCLEOTIDE POLYMORPHISMS OF GH, LEP, MSTN GENES WITH GROWTH CHARACTERISTICS IN MEAT-WOOL AND WOOL SHEEP

The main trend in the development of sheep breeding in the last decade all over the world has become a constant increase in the production of mutton. This study was designed to study polymorphisms of genes GH, LEP, MSTN in two breeds of North Caucasian Meat Wool and Soviet Merino sheep in Russia, as well as to identify potential single nucleotide polymorphisms (SNPs) associated with growth traits to improve the genetic potential of sheep. Parts of the GH, LEP, MSTN genes were amplified in North Caucasian Meat-Wool and Soviet Merino sheep to identify SNPs by Sanger sequencing and using a polymerase chain reaction protocol. These genotypes were correlated with meat traits such as birth weight, growth rate, weaning weight. . Genetic and variance analysis of the data obtained was also carried out. Sheep age and parity had a significant effect (p A) and the LEP gene (c.541G> T), as well as a synonymous replacement of the MSTN gene (c. 212C> A), were revealed. According to the results of studies in the North Caucasian Meat-Wool sheep, three GHCC, GHCT , GHTT genotypes for the GH gene and three LEPGG, LEPGT , LEPТТ genotypes for LEP were identified. The studied region of the MSTN gene in sheep of the North Caucasian meat and wool breed turned out to be monomorphic. According to the results of studies in Soviet Merino sheep, three genotypes GHCC, GHCT , GHTT for the GH gene, three genotypes MSTNСС , MSTNСА , MSTNАА for the MSTN gene, two genotypes LEPGG, LEPGT for the LEP gene were established. The analysis of associations showed a significant effect (p<0.05) of the GHСТ and LEPGT genotypes on the signs of sheep growth. Interestingly, the presence of the T-allele in sheep of the North Caucasian Meat-Wool breed tended to increase in weight during weaning (+2.2 kg) both for the GH gene and for the LEP gene (+ 1.6 kg). Interestingly, similar results were observed in sheep of the Soviet Merino breed, where the missense mutation led to an increase in weaning weight (+ 1.2 kg) for the GH gene and for the LEP gene (+1.3 kg). A synonymous MSTN gene substitution does not lead to a substitution of the coding amino acid, but may further lead to gene expression. The GH, LEP, and MSTN genes are proposed markers for improving growth traits in meat-wool and wool sheep, which will increase the ability to understand the genetic architecture of the genes underlying SNPs that influence such traits

Mef2b gene snp markers of meat productivity in Severokavkazskaya sheep breed

One of the new promising candidate genes defining productive qualities of sheep is MEF2B. Protein from the MEF2 group encoded by it affects the production of myostatin and the expression of the genes responsible for the growth of skeletal muscle fibers. Thus, the knowledge of the MEF2B gene structure is important for genomic selection. We have studied the structure of the MEF2B gene at sheep of Severokavkazskaya breed bred in Russia. To detect alleles we use NimbleGen sequencing technology by Roche (USA). As a result, it was revealed 14 single nucleotide polymorphisms (SNP) at the given breed. The discovered SNPare located in not coding areas. From them 7 polymorphisms are in the area of 5' upstream gene in loci: c.-1713, c.-1319, c.-839, c.-321, c.-246, c.-161, c.-3; 6 polymorphisms are in introns, loci: c.55-51, c.258+312, c.258+380, c.259-52, c.452+95, c.452+ 103, 1 SNP is in 3' downstream gene, c.*252. Two of the identified SNPs are significantly connected with high indices of meat productivity: c.55-51 and c.259-52. At the same time it was not possible to find out the impact on productivity of c.-1713 polymorphism. Our investigation is a base of next research of affection of different MEF2B gene alleles on meat quality and can be used to prepare PCR test-system for genomic selection

POLYMORPHISMS OF THE IGF1 GENE IN RUSSIAN SHEEP BREEDS AND THEIR INFLUENCE ON SOME MEAT PRODUCTION PARAMETERS

Insulin-like growth factor 1 (IGF-1) plays an important role in the growth and development of muscle tissue in animals. Research into the structure of IGF1 in sheep may provide important information for genomic marker assisted selection used to increase meat production. We investigated the structure of the IGF1 gene and the effect of polymorphisms on lifetime meat productivity performance in the Russian Soviet Merino sheep breed. Alleles were detected in 15 rams using NimbleGen sequencing technology by Roche (USA). 18 single nucleotide polymorphisms (SNPs) were found in this breed. Only one SNP – c.-81T>C – was found in the coding region. All other SNPs were located in introns 5’UTR and 3’UTR. The c.-5363C>T, c.-5188G>C, c.-5186G>A and c.-4088G>A polymorphisms, presented together in two alleles of the gene, correlate with a high live weight in a heterozygous state. The synonymous substitution of c.81T>C in the exon was not found to have any influence on the analyzed meat production parameters. One of the detected SNPs – c.-91A>C – had a positive correlation with weight, height, croup parameters and other attributes in rams

Myostatin gene (MSTN) polymorphism with a negative effect on meat productivity in Dzhalginsky Merino sheep breed

One of the most important negative regulator of muscle grow in mammalians is myostatin. Some mutations in myostatin gene (MSTN) can decrease the effect of protein and play role in meat quality of sheep. Therefore, in genome selection, knowledge of MSTN gene structure is very important. We investigated the polymorphism of the MSTN gene and its influence on body parameters in Russian sheep breed Dzhalginsky Merino. To detect alleles, we use NimbleGen sequencing technolog). In this breed, we found 20 single nucleotide polymorphism (SNP). That is SNP in promoter: с.-1866, с.-1404, с.-1401, с.-1213, с.-1128, с.-958, с.-783; 5'UTR: с.-40; exon I: с.101; intron 1-2: c.373+18, c.373+241, c.373+243, c.373+259, c.373+563; intron 2-3: с.747+164, с.747+309, с.748-810, с.748-229G>A, с.748-475; 3'UTR: с.*1232. Three of detected SNP (c.-1128, c.-958, c.-40) have a negative effect on the body parameters – decrease weight, height and other. Other three SNP (c.101, c.373+18, с.*1232) have not significant influence on this parameters. Our investigation is a base of next research of affection of different MSTN gene alleles on meat quality and can be used to prepare a PCR test-system for genomic selection