miRNAs control gene expression in the single-cell alga Chlamydomonas reinhardtii

As siRNAs and miRNAs have only been found in multicellular organisms, it was proposed that RNAi evolution was driven by the need to regulate expression of genes in different tissues. But both siRNAs and miRNAs are present in the unicellular alga, Chlamydomonas, suggesting that the evolutionary history of RNAi will need to be reassessed.