A miRNA can be derived from the each arm of the pre-miRNA hairpin. The least common of these two miRNA products is denoted by the addition of * to the miRNA name. Both miR-10 and miR-10* have been detected in Drosophila. There are many potential targets for miR-10* in Drosophila, including several Hox genes, indicating that miR-10* may also be functional. In Drosophila most mature miR-10 sequences are produced from the 3' arm of the precursor while in the beetle Tribolium castaneum most production comes from the 5' arm. These changes of arm preference during evolution are termed arm switching events, and they are relatively frequent during the evolution of microRNAs.
Read more about this topic: Mir-10 Micro RNA Precursor Family