[
Science,
2001]
Over the years, a steady stream of structural and regulatory RNAs have been identified. Three papers published in this issue on pages 853, 858, and 862 from the Tuschl, Bartel, and Ambros labs continue the tradition, but now prospecting for tiny RNAs of 22 nucleotides (nt). The chain of reasoning that simultaneously attracted these groups to 22 nt is convoluted but interesting.