Özet:

Abstract In the livestock industry, a large, fat tail becomes advantageous in sheep, and therefore, a reduction in the size of the fat tail is often beneficial. Because the difference between Iranian thin and fat tail breeds in fat-related genes are in the tail. So the aim of this study aimed to find candidate genes related to fat deposition between the Iranian thin and fat tail breeds located on chromosome 5 using bioinformatics and molecular techniques. Firstly, we investigated the region placed on chromosome 5 by Genomic Sequence Databases, including Pre Ensemble and UCSC Genome Browser. The local and global alignment of sequences for other species showed a high similarity with a region of chromosome 7 in cattle (up to 95%) is identified as an orthologous region. Additionally, the PPP2CA gene on bovine chromosome 7 was orthologous. Then, we investigated the relationship between the polymorphism of the PPP2CA gene with carcass, growth, and fat tail traits in Lori-Bakhtiari (165 heads) and Zel (140 heads) breeds using PCR-SSCP technique. These data indicated two different banding patterns (genotypes) and two mutations (synonymous and Indel).  The mutations interchangeable lead to the change of nucleotide T to C, then the codon was the switch from TCT to TCC both encode serine. The second mutation was the deletion of the nucleotide T at position 2 of the second pattern, which changed the open reading frame and created the end codon in this region, changing protein function. Finally, the association between genotypes and traits of weaning weight and fat tail weight in Lori-Bakhtiari and cholesterol in Zel breeds was significant (p <0.05). Also, genotypes of the exon1 position in the PPP2CA gene were associated with carcass traits (fat percentage of carcass and triglyceride traits) in the Zel Slaughter breed (p <0.05). The results showed that one of the most distinctive traits was tail fatness and visceral organs of the body in breeds considered. This area of the PPP2CA gene has a significant association with mentioned traits, and can implemented in breeding programs.

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