Archive: Tiny RNAs Discovered (2001)

The discovery of micro-RNAs, announced 22 years ago, launched a huge new effort into epigenetics: cataloging and understanding the many parts of the cell that regulate genes.

This article is reproduced from CEH of October 2001. Some embedded links may no longer work.

Tiny RNAs: A Whole New World of Regulators Discovered  10/26/2001
Cell biologists have uncovered a whole new class of regulators that control development and gene expression: micro-RNAs, or miRNAs. These short sequences of genetic material (usually around 10-30 nucleotides, much smaller than genes) that had “almost escaped detection until now,” may number in the hundreds or thousands in the cells of all living things. They work not by coding for proteins, but by latching onto messenger RNAs, that are en route to the protein assembly plants, and inhibiting them until the right time, thus acting as switches or timing controls. But the range of possible functions is just now beginning to be explored. One geneticist comments, “Each miRNA is probably matched to one or more other genes whose expression it controls. Their potential importance to control development or physiology is really enormous. If there are hundreds of these in humans and each has two or three targets that it regulates, then there could be many hundreds of genes whose activity is being regulated this way.” Three reports on miRNAs are in the Oct 26 issue of Science. See also this summary in SciNews.

Switches, controllers, regulators– is this the language of purposelessness and chance? The microscopic world of the cell just keeps getting more amazing, and harder to explain by evolution. Now we have another category of tools to marvel at.

For subsequent stories on micro-RNAs, epigenetics and the downfall of the “junk DNA” myth, see:

• Genetics Central Dogma Is Dead (12 Sept 2007)
• Epigenetics: the 21st-Century Scientific Revolution (4 July 2012)
• Mutations Are Not the Main Source of Genetic Variety for Evolution (21 June 2022)