The investigation of partial leptin gene intron two polymorphism in Iranian Holstein bulls using PCR-RFLP

Leptin is a protein which is synthesized by adipose tissue. It has 16 kilo Dalton weight and its effect was proven on regulation of feed intake, energy balance, pregnancy and the function of immune system. There are some evidence about association of Leptin gene polymorphism and important economic traits. Uses of genetic markers in optimum selection index increase the accuracy and efficiency of selection in breeding programs. The objective of this study was to investigate the polymorphism of the Intron 2 of Leptin gene in Iranian Holstein proven bulls. Genomic DNA was extracted from frozen semen of 141 Iranian proven bulls and PCR-RFLP was used to detect the genotype of a part of Intron 2 of Leptin gene related to each animals. The AluI and Hinf I restriction enzymes didn’t show any polymorphic pattern in 422 base pair of the above locus but three genotypes AA, AB and BB with frequency equal to 0.823, 0.135 and 0.042 were distinguished respectively for this locus when it was digested by Sau3AI restriction enzyme. Also the C to T transition was detected in one of the Sau3AI restriction sites according to the PBR results. This locus deviated from Hardy-Weinberg equilibrium (p<0.01) and the frequency of allele B was low in Iranian Holstein proven bulls. Results showed that the expected heterozigosity of this locus was low. However, the association of Leptin gene and milk production related traits in Iranian Holstein cows will be one of the important subjects of the feature researches.