London: Scientists at the Broad Institute of Harvard and MIT and Beth Israel Deaconess Medical Center have announced the discovery of a vast new class of previously unrecognised mammalian genes that do not encode proteins, but instead function as long RNA molecules.

The researchers describe their discovery as a novel class of "large intervening non-coding RNAs" (lincRNAs).

According to them, these genes play critical roles in both health and disease, including cancer, immune signalling and stem cell biology.

"We''ve known that the human genome still has many tricks up its sleeve. But, it is astounding to realize that there is a huge class of RNA-based genes that we have almost entirely missed until now," Nature magazine quoted Eric Lander, founding director of the Broad Institute, as saying.

The researchers say that, in comparison with standard "textbook" genes, the newly discovered lincRNAs are thousands of bases long.

Because only about ten examples of functional lincRNAs were known pre