University of Utah geneticist Mario Capecchi got a bonus after winning the Nobel Prize for medicine last fall: He learned he has a younger sister.

Capecchi, 70, and half-sister Marlene Bonelli, 69, met last month in northern Italy. It was technically a reunion, but really more of an introduction; they were too young to remember when they were separated in the early days of World War II.

Bonelli had long believed that Capecchi and their mother had died in the war, he told The Salt Lake Tribune.

Capecchi's mother gave birth to Bonelli in 1939, when her son was a toddler. Lucy Ramberg, a left-leaning American artist who was imprisoned for much of the war, handed over the baby girl to friends living in Austria, where Bonelli still lives.

Bonelli recognized Capecchi's name after he won the Nobel Prize in October and informed the media in Austria that the famous scientist was her brother. The newspaper Dolomiten sent Capecchi photos of Bonelli.

"Looking at the pictures, it was obviously my sister," Capecchi said, noting her resemblance to their mother.

The Dolomiten arranged for the May 23 reunion at a hotel, where the siblings hugged, shared photos and spoke through an interpreter.

"She doesn't speak English and I don't speak German, and neither of us speaks Italian, although I can get away with it in a restaurant," Capecchi said.

The reunion was another dramatic turn in Capecchi's life story.

Born in 1937, Capecchi was separated from his mother during World War II. The two were reunited at the end of the war, when he was 9, and they moved to the United States.

As a child in America, Capecchi started on what became a brilliant academic career.

It was capped off by winning the Nobel Prize, along with two Britons, for work that led to a powerful and widely used technique to manipulate genes in mice, and which advanced the understanding of a range of killer diseases.