MicroRNAs in vertebrate development

The vertebrate genome contains hundreds of small non-coding 'microRNAs' that have been implicated in controlling the expression of potentially thousands of target genes. Presently, only a handful of these targets have been characterized. Recent reports of microRNA 'sensors', microRNA microarrays and the creation of vertebrates that lack all microRNA activity will aid in determining the roles played by microRNAs, and the genes that they regulate, during vertebrate development.