Author Sam Kean explored the complex world of genetics and DNA for his book “The Violinist’s Thumb.”

While researching genetics and DNA for his new book, “The Violinist’s Thumb” — a look at how DNA influences our quirks and tendencies — author Sam Kean decided to make his work even more personal: He submitted his DNA to a genetics testing service. Then, he regretted it.

The test was “kind of a lark for me; I didn’t take it all that seriously,” Kean says. “But then, of course, when I got the results back and they said, ‘You are susceptible to these diseases,’ I thought, ‘Oh, my God, what have I done?’  ”

Ultimately, further research helped him regain perspective.

“The more I looked into it, the more I realized that genes deal with probabilities and not certainties,” he says. “The environment also plays a role” in determining how individuals’ lives play out. It’s a little like the nature-versus-nurture debate — except Kean believes that your genes and your environment work together (rather than against each other) to influence your behavior, personality and more. So, we gathered some personality quirks and asked Kean which factor, exactly, is to blame.


“I have never seen any study that said that hypochondria was genetic,” Kean says. “And, of course, because there are different diseases in different parts of the world, that’s going to depend a little bit on culture, too. People in certain areas just aren’t going to get certain diseases because it’s just not in the environment. So, they probably wouldn’t be worried about those diseases.”

Cat Hoarding

“This is a little bit speculative because [scientists] haven’t done controlled scientific studies of it,” Kean says. “But they do know that there is a [parasite] … called toxoplasma gondii, which [can be found] in kitty litter. It can make mice attracted to cats. It gets inside a lot of other mammals, too, and there’s speculation that that’s why people hoard cats specifically, because it might be sort of producing that attraction.”

Musical Talent

“The story that the book is named for is about [Niccolo] Paganini, a very famous violinist [who] had freakishly flexible fingers,” Kean says. “[Sergei] Rachmaninoff had enormous hands, which allowed him to play music that other pianists simply couldn’t. That said, both Rachmaninoff and Paganini worked incredibly hard and they both had a passion for music, too. You need genes to give you the right physical traits to do those kind of things, but you also need a sort of mental aptitude as well.”

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