microRNAs: Runts of the genome assert themselves

microRNAs form an abundant class of 21-22 nucleotide, non-coding RNA that is common to diverse species of multicellular life. Although they are currently the subject of intense, directed study, the path toward their discovery has been dominated by chance and serendipity. In this review, I examine how these tiny molecules have risen from genetic obscurity to scientific stardom, and discuss the emerging biological functions of these novel riboregulators.