Polymorphism within the intron region of the bovine leptin gene in Iranian Sarabi cattle (Iranian Bos taurus).

The main goal of breeders is breeding superior animals. Most traits of the economic importance in farm animals are determined by polygenic loci with environmental factors. Progress in animal breeding may be improved by combining traditional performance data with molecular genetic information on quantitative loci in selection index. Candidate genes are chosen for study on the basis of known relationships between biochemical and physiological processes. Leptin is 16 KD protein that is synthesized by adipose tissue and it is involved in the regulation of feed intake, energy balance, fertility and immune functions. In cattle, the leptin gene is located on chromosome 4. It consists of 3 exons and 2 introns of which only two exons are translated into protein. Sixty six animals were genotyped for this project. A PCR was carried out between 2 exon (intron 2). A strategy employing polymerase chain reaction was used to amplify a 422 bp from blood, semen, hair root and milk DNA. Digestion of polymerase chain reaction products with Sau3AI revealed two alleles: Allele A was 390, 32 fragments and allele B was 303, 88, 32 (only 303 fragment visible on the gel). Three patterns were observed and frequencies were 0.31, 0.43, and 0.14 for AA, AB and BB respectively. This polymorphism could be further evaluated for marker assisted selection and developed PCR methodology would expedite screening for large numbers of animals required for such studies.