It was the first to be discovered of the miRNAs, a class of non-coding RNAs involved in gene regulation. miRNAs are transcribed as ~70 nucleotide precursors and subsequently processed by the Dicer enzyme to give a 21 nucleotide product.
The discovery of this was the first instance of the identification of miRNAs, a class of non-coding RNAs that regulate genes. miRNAs are initially transcribed as ~70 nucleotide precursors and then processed by the Dicer enzyme to produce a 21 nucleotide product.