Abstract

Pituitary transcription factor (Pit-1) has been shown to be a positive regulatory factor of growth hormone, thyrotrophin β - subunit (TSH- β), and prolactin in the mammalian pituitary. Pit1 gene structure consists of 6 exons and 5 introns. The objective of the present study was the identification of Pit1 genotypes in Holstein and Iranian native cattle. DNA was extracted from 434 blood samples of 224 Holstein and 210 native cattle for genotyping ofPit1 gene by PCR-RFLP assay. The PCR product of the specific primer Pit1-F and Pit1-R gives the 451 bp specific band. Pit-1 gene was amplified by specific primers and PCR products were digested with HinfI restriction enzyme. Electrophoresis results indicated 244 and 207 bp fragments for BB and a single 451 bp fragment for AA alleles. Also, three fragments contain 451, 244 and 207 bp was observed for heterozygote ABgenotype. The frequency of the A and B alleles of this gene were 29.8 and 70.1% in Holstein and 74.9 and 25% in Iranian native cattle respectively. These findings showed that AA genotypes of Pit1 gene could be use in fertility and create the next generation for increase in milk production and growth of Iranian cattle.

Key words: PCR-RFLP, Pit1 gene (POU1F1), genotyping, Holstein, native cattle.