The miR-124 microRNA precursor is a small non-coding RNA molecule that has been identified in flies, nematode worms, mouse and human. The mature ~21 nucleotide microRNAs are processed from hairpin precursor sequences by the Dicer enzyme, and in this case originates from the 3′ arm. miR-124 has been found to be the most abundant microRNA expressed in neuronal cells. Experiments to alter expression of miR-124 in neural cells did not appear to affect differentiation. However these results are controversial since other reports have described a role for miR-124 during neuronal differentiation.