miRNAs 研究非常之火，在藻类里面同样存在！

MicroRNAs (miRNAs) in eukaryotes guide post-transcriptional
regulation by means of targeted RNA degradation and translational
arrest1. They are released by a Dicer nuclease as a 21–24-
nucleotide RNA duplex from a precursor in which an imperfectly
matched inverted repeat forms a partly double-stranded region.
One of the two strands is then recruited by an Argonaute nuclease
that is the effector protein of the silencing mechanism. Short
interfering RNAs (siRNAs), which are similar to miRNAs, are also
produced by Dicer but the precursors are perfectly doublestranded
RNA. These siRNAs guide post-transcriptional regulation,
as with miRNAs, and epigenetic genome modification.
Diverse eukaryotes including fungi, plants, protozoans and metazoans
produce siRNAs2–5 but, until now, miRNAs have not been
described in unicellular organisms and it has been suggested
that they evolved together with multicellularity in separate plant
and animal lineages6. Here we show that the unicellular alga
Chlamydomonas reinhardtii contains miRNAs, putative evolutionary
precursors of miRNAs and species of siRNAs resembling
those in higher plants. The common features of miRNAs and
siRNAs in an alga and in higher plants indicate that complex
RNA-silencing systems evolved before multicellularity and were
a feature of primitive eukaryotic cells.