Abstract: The part of the bovine genome which shows a superior action and explains the major part of variation of the economical production traits were known as QTL. PIT1 gene which is also termed hormone factor-1 is a pituitary-specific transcription factor which has responsible for pituitary development and hormone expression in mammals. The main function of PIT1 is for binding and trans-activity promoters of both Growth Hormone (GH) and Prolactin (PRL) gene. It was subjected to different molecular studies as a key role for understanding genetic variation in dairy cattle. This study was aimed to detect the polymorphism in a part of PIT1 gene, exon 6 in Najdi cattle. DNA was extracted from blood sample collected from 84 Najdi Cattle and submitted for Polymerase Chain Reaction (PCR) followed by digestion with HinfI restriction enzyme. Base on PCR-RFLP method, it found that the frequency of the A and B alleles of this gene for Najdi Cattle were 18.45 and 81.55%, respectively. The genotypic frequencies of AA, AB and BB were 3.57, 29.76 and 66.66%, respectively. χ2-test indicated that these two populations were at Hardy-Weinberg equilibrium. Thus, the selection base on these loci in the population is possible to be done.
M.T. Beigi Nassiri, Z. Biranvand, T. Hartatik, J. Fayazil and S. Tavakoli, 2010. The Study of PIT1 Gene Polymorphism in the Najdi Cattle Using PCR-RFLP Method. Journal of Animal and Veterinary Advances, 9: 2001-2003.