Two Americans -- Andrew Z. Fire and Craig C. Mello -- shared the Nobel Prize in medicine on Monday for their work in controlling the flow of genetic information.

The two U.S. scientists, Fire, of the Massachusetts Institute of Technology, and Mello, of Harvard University, were honored for their discovery of "RNA interference _ gene silencing by double-stranded RNA," according to the Karolinska Institute in Stockholm.

"This year's Nobel Laureates have discovered a fundamental mechanism for controlling the flow of genetic information. Our genome operates by sending instructions for the manufacture of proteins from DNA in the nucleus of the cell to the protein synthesizing machinery in the cytoplasm. These instructions are conveyed by messenger RNA," the institute announced.

Their discovery, published in 1998, is important in the defense against viruses and paves the way for novel therapies to reverse crippling disease.

Last year's medicine prize went to Australians Barry J. Marshall and Robin Warren for their pioneering research on stomach ulcers, discovering that bacteria, not stress, causes the ulcers.

The Nobel prizes, founded by Swedish industrialist Alfred Nobel, the inventor of dynamite, were first awarded in 1901. The Nobel prizes include such categories as literature, peace, medicine, physics and chemistry.

The Physics prize will be announced on Tuesday and Chemistry on Wednesday. The Economics prize, awarded by Sweden's central bank, the Riksbank, is scheduled for Oct. 9.

The Literature prize is traditionally awarded on a Thursday, while the announcement of the Peace Prize is expected on Oct 13.

Laureates this year will receive a gold medal and share 10 million Swedish kronor (1.37 million U.S. dollars).

Source: Xinhua