Investigation of Polymorphism of Dgat1 Gene and Its Association With Body Size and Tail Dimensions Traits in Sanjabi Sheep

Background and aim: dgat1 is a microsomal enzyme that accelerates the final step of synthesis of triglycerides, namely conversion of diacylglycerol to triacylglycerol. the aim of this study was to identify mutations in dgat1 gene and their relationship with body size traits and dimensions tail in sanjabi rams.methods: blood samples from 96 rams were taken and tail length, tail width, tail circumference, body length, body width and height were simultaneously recorded. dna was extracted from blood and a pair of specific primers was used to amplify a 824 bp fragment including of exons 13 to 17 of the dgat1 gene. by sequencing for some samples, it was found that three mutations c8539t, c8522t and t8357g have occurred in exon 17 and intron 16 regions of the gene. therefore, pcr products were digested with alui, bsh12361 and adel restriction enzymes in order to genotype all animals in these regions. the collected data was analysed using sas software and proc glm with significant level of 0.05 to show significant differences.results: the results of alui digestion for exon 17 of c8539t showed two cc and ct genotypes with frequencies of 0.76 and 0.24, respectively. digestion of pcr products by bsh 12361 restriction enzyme for exon 17 of c8522t position showed two cc and ct genotypes with frequency of 0.91 and 0.09, respectively. adel restriction enzyme for intron 16 t8357g also revealed three tt, tg and gg genotypes with frequencies of 0.70, 0.29, 0.01, respectively. the results of assosiation analyse showed that there was no significant relationship between different genotypes of dgat1 and body size traits (p <0.05). however, there was a significant relationship between genotypes of c8522t mutation and tail length (p <0.05). the animals with cc genotype had the highest tail length scale compared to ct genotype (p <0.05). the results also showed that the polymorphism in tg357g locus of dgat1 gene was significantly correlated with tail length and tail length as animals with gg genotype had the highest tail length compared to other genotypes (p> 0.05), and the animals with tt genotype had the highest tail width compared to other genotypes (p> 0.05).conclusion: in this research, investigation of genetic polymorphisms at the dgat1 gene showed that this candidate gene can used as one useful tool in sheep breeding and selection programs but it seems that more studies with more samples on other sheep breeds are necessary to confirm results of this research.