Abstract

We used the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique to screen for DNA polymorphisms of the leptin gene in 255 cows of Iranian Holstein. Amplified region is located in exon 3 of leptin gene. The genomic bovine leptin sequences, which consist of three exons, were obtained from GeneBank (Accession number U50365). Genotype frequencies in all herds were 0.588, 0.388 and 0.024 for AA, AB and BB, respectively, and allelic frequencies were 0.782 and 0.218 for A and B, respectively. We investigated effect of A59V polymorphism in the leptin gene on three reproduction traits. Significances of the genotype effects were tested using approximated F-statistic provided by SAS (v.8, GLM procedure). This study showed that genotype had no effect on open days and calving interval (NS) but had significant effect on length of pregnancy (P < 0.01). Animals with the AA genotype had higher length of pregnancy than other genotypes.

Key words: Leptin, Iranina Holstein, polymerase chain reaction-restriction fragment length polymorphism, reproduction trait.

Abbreviation

PCR-RFLP, Polymerase chain reaction-restriction fragment length polymorphism; QTLs, quantitative traits loci; NBTA, nutrient bromothymol blue agar; LH, luteinizing hormone.