My Genes And Me

What can your genome tell you about yourself?

High school genetics taught me a thing or two: I would never have red-headed children, and that growth spurt I hoped would eventually happen was, at best, a remote possibility.

But it turns out our DNA can tell us more than just our hair color or height. A year and a half ago, my family took part in the Genographic Project, a nonprofit collaboration between National Geographic and IBM (nyse: IBM - news - people ), aiming to discover the migratory patterns of human groups out of Africa. My cousin volunteered her genetic data, swiped her cheek with a cotton swab and sent it off to a lab for DNA analysis. I already knew my immediate ancestors were Roman Catholics from Spain. But it turned out they took a circuitous route to the Iberian Peninsula: from Eastern Europe to Scandinavia to probably France before settling near Barcelona.

Science has evolved rapidly since the Genographic Project launched in 2005. Now, you can simply spit into a vial and send it off to several genetic-testing start-ups, such as 23andme and the nonprofit Personal Genome Project. These companies will tell you some interesting stuff--not just the migratory patterns of your ancestors but your predispositions for certain diseases or why you don't like Brussels sprouts (a sliver of DNA that allows you to taste a bitter compound in vegetables).

"For science and individual health and identity, I think we're in a key time," says Mary Sue Kelly, a 63-year-old retired psychiatrist who has had her DNA analyzed by the Genographic Project and Navigenics, a disease-focused genetic-testing start-up. "I've made the analogy of when the first mirror was seen--that must have flipped out a whole bunch of people for a long time, or when the first camera came. I think this is as illuminating as that--the first time you saw yourself and just 'Oh my word, that's what I look like?' "

My results from the Genographic Project didn't quite rock my world, but they were surprising. "Guess what we are," my aunt exclaimed when the results came in. I had always thought, due to my grandmother's darker complexion, that I was descended from Arabs who had come to Spain during the expansion of the Ottoman Empire. But I was wrong. "We're Jewish," my aunt said, as my grandmother shook her head incredulously in the seat across from us. "Eastern European Ashkenazi Jews." I briefly wondered if this explained my attraction for Jewish men, shrugged and went back to my book.

I recently, however, decided to dig a little deeper. A search on Ashkenazi Jews brings up some fascinating details--we're really smart, and we were heavily involved in the ostrich-feather trade. But Ashkenazi Jews are also susceptible to a host of scary-sounding genetic diseases, such as Fanconi anemia--associated with short stature (check); bone marrow failure (yikes, I hope not); a predisposition to leukemia and other cancers (my mother had cancer); and Cystic Fibrosis.

Since the Genographic Project is an anthropological study, it doesn't tell me what chance I have of developing any of these diseases. But other genetic-testing companies can, at least to some extent.