A customer of the Web-based service 23andMe sends in a sample of spit and, for about the cost of a Sony PlayStation 3, receives a genome-wide analysis of nearly 600,000 genetic variations. The results include an estimate of genetic risk for various diseases, along with other personal information, such as where the customer’s ancient ancestors might have come from.

The service’s $399 price tag and its analysis of some quirky genetic traits, such as type of earwax, ­epitomize Linda Avey and Anne Wojcicki’s ­populist approach to the genome. Avey, whose expertise is in business development for the biotechnology industry, and Wojcicki, who has a background in health-care investing, have also given the service a twist by harnessing the popularity of social networking; clients can compare their genomes with those of friends and family. TR senior editor Emily Singer recently visited Avey and Wojcicki at their offices in Mountain View, CA, to find out what it’s like to delve into one’s own genome.

TR: What does it mean to share your genome?

Avey: We have two levels of sharing. At the basic level, you don’t view specific genetic information, but you can compare yourself across your entire genetic data set. You could look to see if you are part of the same haplogroup [a designation of ancient ancestry] as a friend.

With extended sharing, you open up part of your genome information to others. You might do that with siblings or close friends. For example, we have a feature called family inheritance. If you have data on three generations of a ­family and plug in all three, you can see how a particular set of genes, like the genes for circadian rhythm, were passed down. If you compare genomes with a sibling, you can see if you received the same chunk of chromosomes from both parents. Siblings look like identical twins at some parts of the genome.

TR: What will be one of the first examples of genetic information someone might use to make a medical decision?

Wojcicki: One of the areas we’ve talked a lot about is pharmacogenomics–being able to say, should you take ibuprofen? Or if you have a new baby and you’re flying to Europe, should that child take Benadryl, or will it make them hyper?

TR: What are the downsides of this kind of genetic testing?

Avey: You could find out the person you thought was your father is not your father. We point that out in the consent form. On the health side, we don’t test for more serious conditions like ­Huntington’s disease.