STOCKHOLM, Oct. 2 (Xinhua) -- U.S. scientists Andrew Fire and Craig Mello won the Nobel Prize in physiology or medicine Monday for discovering a powerful way to turn off the effect of specific genes, opening potential new paths for disease treatment.

"This year's Nobel laureates have discovered a fundamental mechanism for controlling the flow of genetic information," the jury declared.

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.

Fire, 47, of Stanford University, and Mello, 45, of the University of Massachusetts Medical School, showed through experiments with nematode worms that a particular form of ribonucleic acid, or RNA, can "silence" or switch off targeted genes in a process known as RNA interference. Their discovery was published in 1998.

"RNA interference" is already being widely used in basic science as a method to study the function of genes and it is being studied as a treatment for infections such as the AIDS and hepatitis viruses and for other conditions, including heart disease and cancer.

The Karolinska Institute said it is important for regulating the activity of genes and helps defend against viral infection.

The Medicine Prize opened this year's series of prize announcements. The Physics prize will be announced on Tuesday and Chemistry on Wednesday. The Economics prize, awarded by Sweden's central bank, is scheduled for Oct. 9.

The Literature prize is traditionally awarded on a Thursday, though the actual date is only announced 48 hours in advance. It is expected to be announced on either Oct. 5 or Oct. 12.

The announcement of the Peace Prize in Oslo, Norway, will wrap up the Nobel season on Oct. 13.

The Nobel prizes, founded by Swedish industrialist Alfred Nobel, the inventor of dynamite, were first awarded in 1901.

The Swedish inventor of dynamite established the prizes in his will in the categories of literature, peace, medicine, physics and chemistry. The economics prize is technically not a Nobel but a 1968 creation of Sweden's central bank.

This year's laureates will receive a gold medal and share 10 million Swedish kronor (1.4 million U.S. dollars).

The formal awarding will take place in Stockholm on Dec. 10 -- the anniversary of Nobel's death in 1896. All prizes are handed out in Stockholm except for the peace prize, which is presented in Oslo. Enditem