Northern Blot is a molecular biology technique used to detect and analyze RNA. The method includes RNA electrophoresis, transfer to membrane, RNA immobilization, RNA probe hybridization and detection. It is commonly used to measure the mRNA levels of specific genes, study gene expression regulation, and the size and structure of RNA. Although Northern Blot provides useful information in RNA analysis, it has been replaced by more advanced technologies such as RT-PCR and RNA sequencing in recent years due to its tedious operation and relatively low sensitivity.