Expression Profiling and Discovery of microRNA

miRNAs, on average comprised of 22-nucleotides with small non-coding RNAs, regulate the gene expression of targeted genes. Thousands of miRNAs have been identified, having biological significance in many pathways. These microRNAs have also been used as biomarkers for diagnostic and agricultural purposes. Thus, this chapter attempts to describe in brief miRNA biogenesis pathways, miRNA profiling methods, and bioinformatics tools of miRNA profiling. Additionally, we will discuss the role of mi RNA and its applications. miRNA biogenesis can be broadly categorized into canonical and non-canonical pathways. There are various sample types and miRNA extraction procedures. miRNA sequences, once extracted, can be subjected to various computational tools that may aid in understanding its structure and functions. However, few researchers have suggested that there is still scope for developing these tools with appropriate algorithms for avoiding false positive results.