Nobel Prize for Medicine - stem cell research

The scientists created a technology to genetically engineer so-called ``knockout'' mice, animals missing a particular gene, the Stockholm-based Nobel Foundation said today in a statement.

Their discovery fuels the work of researchers who study the development of embryos, the genesis of diseases or the workings of cells. The technique is used to disable or weaken single genes, illuminating their roles in disease and aging, and has produced more than 500 mouse models of human disorders such as hypertension and cystic fibrosis, which may aid drug studies.

``This is staggering,'' Capecchi, 70, said in an interview. He called the 3 a.m. phone call from Sweden ``a huge surprise.''

Capecchi was born in Italy, where he was forced to wander the streets for four years after his mother was imprisoned by the Nazis in a concentration camp. His mother found him after World War II and brought him to live with his aunt and uncle in the U.S. He completed his thesis work under James D. Watson, who won the Nobel Prize in Medicine along with Francis Crick in 1962 for their work on the structure of DNA.

Now a human geneticist at the University of Utah in Salt Lake City, Capecchi and Smithies, 82, of the University of North Carolina at Chapel Hill, showed how a mouse's genetic information can be permanently changed, creating animals that pass down their disease traits to their offspring.