Fire and Mello's discoveries offer "exciting possibilities" for use in gene technology, said the prize-giving body, the Nobel Assembly of Stockholm's Karolinska Institute.

"It's amazing. It just hasn't sunk in yet," Mello told Reuters from his home in Massachusetts after learning that he would share the prize of 10 million Swedish crowns ($1.37 million) with Fire.

Fire, 47, and Mello, 45, showed through experiments with nematode worms that a particular form of ribonucleic acid, or RNA – the cellular material that transmits genetic information – can "silence" or switch off targeted genes in a process known as RNA interference (RNAi).

They published their findings in 1998. This technology has become a hot area of research for pharmaceutical and biotechnology companies, who view it as a promising new way to tackle a range of conditions.

"I had an inkling that it might be possible, but I am only 45 so I thought it might happen in 10 or 20 years or so," Mello told Reuters, saying the two may give some of the money to charity. The Nobel science prizes are usually given for work done decades earlier.

The Nobel prizes in medicine, physics, chemistry, literature and peace were established by dynamite inventor Alfred Nobel and have been given out since 1901. Fire and Mello are the first of the 2006 prize winners to be announced.

Fire told Swedish radio he was very happy.

"At first it was difficult to believe," he said. He said it was "very nice" to have won and to have "positive attention."

"I am still the same person, my goals are still fairly simple goals of research and science and teaching and family and I don't expect that to change."

Fire earned his Phd in biology in 1983 at the Massachusetts Institute of Technology and is now a professor of pathology and genetics at Stanford University School of Medicine. Mello has a Harvard doctorate and is a professor of molecular medicine at the University of Massachusetts Medical School.

The Massachusetts school said RNAi was now a state-of-the-art method and that a number of companies had bought licenses for the mechanism.

It mentioned companies including Novartis AG, Bristol-Myers Squibb, Monsanto Co., GlaxoSmithKline and Pfizer had bought licenses, co-owned by the school and the Carnegie Institution, to help in treatment development.

Source: Reuters