CHICAGO, Oct 9 (Reuters) Mario Capecchi, the Italian-born winner of the 2007 Nobel Prize in Physiology or Medicine, got his earliest education in the school of hard knocks.
As a young child, Capecchi spent four years living on the streets in Italy after his mother was imprisoned in a Nazi concentration camp as a political prisoner.
''I was three and a half when she was taken to Dachau,'' said Capecchi, who was born in Verona in 1937.
''She put me with a peasant family in Italy because she thought I would be more likely to survive without her,'' he said in a telephone interview.
''Then, that money ran out, and I was in the streets from four and a half to age 9,'' he said, adding, ''I won't tell you how I survived, but I broke a few rules.'' He gave more harrowing details in a 1997 interview with the University of Utah.
''I headed south, sometimes living in the streets, sometimes joining gangs of other homeless children, sometimes living in orphanages and most of the time hungry,'' he said.
He spent the last year in the city of Reggio Emelia, hospitalized for malnutrition. Capecchi's mother found him there after searching for a year after the end of World War II and they made their way to the United States.
There his luck changed, although he started out speaking no English.
''I also was very fortunate. My mother's brother was living in the United States. He was a very good physicist. That got me introduced into science. I actually started out in physics and then switched over into biology,'' Capecchi said.
Now a distinguished professor of human genetics and biology at the University of Utah, Capecchi thinks his years on the street may have contributed to his tenacity as a scientist.
In the lab, Capecchi applied that doggedness to creating ''knockout mice,'' a research technique of breeding mice that lack a specific gene, a process that helps scientists understand how individual genes function.
''One of the things you have to do is be stupid enough to continue in a project when most other people give it up,'' he said.
''When we initiated the work, the goal was to alter genes in the mouse. But the technology wasn't there. The cells to do it weren't there. But the vision was there,'' he said.
Capecchi describes his road to the Nobel Prize as ''pure luck.'' And his hope is that other young scientists might be given opportunities and resources to prove what they can do.
''One thing you can take from my own experience is you can't predict where people will come from, so you should open up possibilities for everyone,'' he said.
REUTERS TB AS0624