Analysis of The Expression Profile of micro-RNA in Cattle Mammary Glands to Identify The Biological Pathways Involved in The Milk Production

The aim of animal breeding is the genetic improvement of traits that have a significant effect on the profitability of livestock units. One of these productive traits is milk production, in which milk and its products are sources of protein and calcium in human nutrition. An appropriate solution for improving these traits is the identification of micro-RNAs that affect milk production and its compounds. Micro RNA is a single stranded and short-chain RNA that has a length of about 22 nucleotides and is present in all cells and body fluids such as blood and milk. In this study, a micro RNA expression profile from the ArrayExpress database was used to study the effect of micro-RNA on the production of milk by samples of bovine mammary tissue. microRNA expression analysis was performed with GEO2R software and then using the miRwalk and targetscan softwares, the target genes for microRNA was detected. After identifying target genes, DAVID software was used to perform ontology analysis and identify the metabolic pathways associated with target genes. Finally, Cytoscape software was used for construction and analysis of the network. In this study, 23 microRNAs with high and low expression were identified whiche were expression regulators of 936 genes. The most important found pathways affecting milk production were TGFβ, WNT, MAPK, mTOR, PI3k-Akt, insulin, and prolactin pathways. Therefore, the results of this study can provide additional information for understanding the relationship between the effective genes and their biological functions in the milk production process.