Human genetic variation and its effect on miRNA biogenesis, activity and function.

miRNAs are small non-coding regulators of gene expression that are estimated to regulate over 60% of all human genes. Each miRNA can target multiple mRNA targets and as such, miRNAs are responsible for some of the 'fine tuning' of gene expression and are implicated in regulation of all cellular processes. miRNAs bind to target genes by sequence complementarity, resulting in target degradation or translational blocking and usually a reduction in target gene expression.