She attended high school at his alma mater, a Quaker boarding school in Pennsylvania. "Quakers don't believe in things. They believe it's what you do with your mind and spirit that's important," Capecchi says. It was a message he and Fraser passed on.

Ask Misha what it was like to have a noted scientist as a father and she pauses. He was gone a lot, she says. But he made time for her.

They played soccer and hiked. She spent hours in his lab, which she loved because of the brightly colored Post-It notes that were stuck everywhere. She grew up knowing the basics and importance of gene targeting "but not in an overbearing way."

She's in college in California but in the middle of last-minute preparations for a yearlong trip to Italy, where she'll work on an organic farm.

While colleagues of Capecchi like Suzanne Mansour describe him as "the smartest person I've ever known," and some predict he'll one day win a Nobel Prize, Misha describes a father who's "emotional but very reserved."

He draws science into every aspect of life, she says, and "takes situations from a very scientific point of view."

He also talks to her "a fair amount" about what he's doing. Last summer, she worked in his lab, and she understands it better now.

Much of their time together was spent "working out" and hiking. They run together. And the three of them like to eat out "a lot."

He's "grouchy" only if he doesn't get to exercise. And, she adds, he sometimes "zones out" in front of the TV.

Fraser and Capecchi like to travel together, walk their dogs in the evenings and talk politics. (They're both fairly liberal Democrats, she says.) They love good food, "but we don't cook very well because we don't make time for it," she says. "But Mario's a good cook. I think a lot of biochemists are; the skills are similar."

He spends his days at the genetics institute; she hangs out at a horse farm for both work and pleasure. She hoped horses would be a love the family could share, but while Capecchi and Misha like the animals, they lack Fraser's passion.

Their friends are divided 50-50 between scientists and "horse" people. He's "equally comfortable" with both groups, she says. And "pretty quiet with both groups."

There's no question Capecchi is shy. But his eyes sparkle with humor. Ask Fraser to describe his sense of humor, though, and she fumbles for words, then suggests you ask one of his close friends, perhaps the neurobiologist with a similar wit.

"I think he has sort of a sarcastic sense of humor without the mean," Fraser says. "Sort of a play on words. Mario is blessed with a pretty good demeanor; he's happy most of the time. He has a good sense of humor and he enjoys laughing."