2009 by Taylor & Francis Group, LLC. MicroRNAs (miRNAs) are small noncoding RNAs regulating gene expression through mRNA degradation or translation inhibition [1-3]. MicroRNAs were first discovered in the nematode, Caenorhabditis elegans, and then identified in numerous plant and animal species [2, 4-7]. A miRNA is defined as a single-stranded RNA 19-25 nucleotides (nt) in length generated from endogenous transcripts that form local hairpin structures [1, 8, 9]. The majority of miRNA genes are located.
