Study of the polemorpyism in the exon 20 leptin receptor in native cow breeds of Sistani, Golpayegani, Najdi and Sarabi

The objective of the present investigation was to study genetic variations in the exon of leptin receptor gene of Iranian cattle breeds. Blood samples were randomly collected from 53 Sistani، 129 Sarabi، 42 Najdi and 72 Golpaygani cattle breeds. Genomic DNA was extracted from blood using guanidium thiocyanate-silica gel method. A 197 bp fragment from exon 20 of the bovine leptin receptor gene was amplified using the polymerase chain reaction. Digestion of PCR products with FokI restriction endonucleases enzyme differentiates two C and T alleles. The T allelic frequency was 0. 094، 0. 225، 0. 095 and 0. 083 in Sisatni، Sarabi، Najdi and Golpaygani cattle breeds، respectively. The CC and CT genotypes were observed in all breeds but TT genotype was not found in any breed. Genotypic frequencies for CC and CT were (0. 811، 0. 189)، (0. 550، 0. 450)، (0. 810، 0. 190) and (0. 833، 0. 167) in Sistani، Sarabi، Najdi and Golpaygani cattle breeds، respectively. The Average Heterozygosity was 0. 1709، 0. 3485، 0. 1723 and 0. 1528، in Sistani، Sarabi، Najdi and Golpaygani cattle breeds، respectively. Among all populations just Sarabi was not in Hardy-Weinberg equilibrium with respect to Leptin receptor gene.