Research Concerning the Polymorphic Expression of Pit-1 and STAT5A Genes in Cattle

Abstract

Recent advances in molecular genetic techniques led us to make possible the accession of a large number of polymorphisms at DNA level in the international database. Some of them are molecular markers and genotyping many individuals for this loci makes possible the association with important economical traits, which can lead to faster genetic gain when information is used in molecular assisted selection. The somatotropic axis plays an important role in the control of the regulation of metabolism and physiological process through growth hormone (GH) and insulin-like growth factors (IGF-I and IGF-II) and their associated receptors. The pituitary transcription factor - Pit1 is the cellular specific transcription factor for activating expression of the prolactin (PRL) and GH genes in the anterior pituitary gland. The STAT5 transcription factors initiate the growth process in the target cells, a process mediated by the pituitary growth hormone. This evidence makes possible to test association between polymorphisms of these genes and quantitative traits in animal population. Two PCR-RFLP polymorphisms (Pit1/ Hinf 1 and STAT5A/ Eco 88I) were tested in order to establish the association with milk performance traits (milk yield, fat and protein content) in Romanian Simmental cattle. The average of milk yield, fat and protein content was in favor of A allele (p<0.001) for Pit-1 gene and only the difference in average of fat content was statistically significant (p<0.05) in favor of C allele in STAT5A gene.