Mario Capecchi and Oliver Smithies of the United States and Martin Evans of Britain won the Nobel Medicine Prize yesterday for their work in creating "knockout mice," the 21st-century testbed for biomedical research.
The trio were honoured for discovering how to genetically manipulate mouse embryonic stem cells, leading to lab rodents that replicate human disease, the Nobel jury said in its citation.
Their "ground-breaking discoveries concerning embryonic stem cells and DNA recombination in mammals ... led to the creation of an immensely powerful technology," the committee said.
The discovery is technically called gene targeting but is commonly known as gene "knockout."
Engineered mice provide researchers with a lab model that is yielding insights into the fundamentals of diseases ranging from Alzheimer's to cancer and the response to new drugs, the jury said.
"Gene targeting in mice has pervaded all fields of biomedicine. Its impact on the understanding of gene function and its benefits to mankind will continue to increase over many years to come," it said.
To date more than 10,000 mice genes -- approximately half of the genes in the mammalian genome -- have been knocked out.
Capecchi, born in Italy in 1937, is a human genetics and biology professor at the University of Utah, while British-born Smithies is a professor of pathology at the University of North Carolina.
Evans, born in 1941, is the director of the School of Biosciences and professor of mammalian gentics at Cardiff University in Britain.
Last year, the prize went to two US scientists, Andrew Fire and Craig Mello, for discovering how to silence malfunctioning genes, a breakthrough which could lead to an era of new therapies to reverse crippling disease.
The medicine prize is the first award to be announced in this year's Nobel season.
The physics prize is to be announced on Tuesday followed by the chemistry prize on Wednesday. The literature prize will be announced on Thursday and the peace prize on Friday.
The economics prize will wrap up the awards on October 15.
The Nobel prizes, founded by Swedish industrialist Alfred Nobel, were first awarded in 1901.
Nobel, the inventor of dynamite, died childless in 1896, dedicating his vast fortune to create "prizes to those who, during the preceding year, shall have conferred the greatest benefit on mankind."
Laureates receive a gold medal, a diploma and 10 million Swedish kronor (1.53 million dollars, 1.08 million euros), which can be split between up to three winners per prize.
The formal awarding of the prizes will take place in Stockholm on December 10.