The evolution and functional diversification of animal microRNA genes.

Research paper by Na N Liu, Katsutomo K Okamura, David M DM Tyler, Michael D MD Phillips, Wei-Jen WJ Chung, Eric C EC Lai

Indexed on: 20 Aug '08Published on: 20 Aug '08Published in: Cell Research


microRNAs (miRNAs) are an abundant class of approximately 22 nucleotide (nt) regulatory RNAs that are pervasive in higher eukaryotic genomes. In order to fully understand their prominence in genomes, it is necessary to elucidate the molecular mechanisms that can diversify miRNA activities. In this review, we describe some of the many strategies that allow novel miRNA functions to emerge, with particular emphasis on how miRNA genes evolve in animals. These mechanisms include changes in their sequence, processing, or expression pattern; acquisition of miRNA* functionality or antisense processing; and de novo gene birth. The facility and versatility of miRNAs to evolve and change likely underlies how they have become dominant constituents of higher genomes.