The Very Meaning of "Gene" Will Change

Christopher Wills : scientist
The traditional definition says a gene is a region of DNA that encodes for a protein.

But in recent years, scientists have discovered stretches of so-called junk DNA that don't make proteins but are nonetheless important.

For example, some regions of DNA appear to hold instructions for producing a DNA-like, but non-proteinaceous, molecule type called double-stranded RNA.

"These double-stranded RNAs"—part of the body's RNA interface or RNAi—"turn out to be very strong regulators of the way that genes function," Wills said. (Find out why the discovery of RNAi led to a Nobel Prize.)

Some double-stranded RNA, for example, can "silence" genes by preventing their protein products from being produced. They do this by binding to and blocking a messenger molecule in the protein-creation pathway, called messenger RNA.

Wills estimates that if bits of double-stranded RNA were counted as genes, they would double the estimated number of genes in the human genome.

"As far as I'm concerned, I'm happy to call them genes without worrying about semantics," he said.