Your Genome is Just a Click Away

In the 1997 science fiction thriller Gattaca, Ethan Hawke's character fights to make a life for himself in a world where pervasive genetic testing and manipulation has left the imperfect by the wayside. At the time, it was easy to dismiss the film as a futuristic flight of fancy, not an issue that people would be facing in the next 10 years. After all, the Humane Genome Initiative already had spent years trying to sequence a single man's DNA, and had years left to go.

But, as often happens in technology, the science of genomics followed a "hockey stick" curve. The initial breakthrough of a single sequenced genome required the development of new sequencing techniques, which have drastically reduced the cost and time required.

Currently, commercial services will deliver an entire sequenced genome in less than a month, and there is a concerted effort to reduce that price to under US$1,000. Meanwhile, several companies offer consumers the ability to get vast amounts of their genetic data for as little as $400. Personal genomics, so recently science fiction, is now a click away on the Internet. But while this information may offer new insights for individuals into their heritage and physical characteristics, the possibility of a Gattaca-like future suddenly doesn't seem so far-fetched.

The two best-known personal genomic services, 23andMe and deCODEme, both operated in essentially the same manner. After visiting their web site and paying for the testing ($1,000 for deCODEme, $400 for 23andMe), a kit is sent in the mail. The consumer either rubs a stick shaped like a large tongue depressor against the inside of their cheek, or provides a (somewhat voluminous) sample of their saliva. The kit is returned to the company, which then processes the sample.

After a few weeks, the customer's genetic data becomes available on the website. But what he gets is not his complete genetic sequence. Instead, he gains access to as much as a million of their Single Nucleotide Polymorphisms (SNPs). Human DNA is, on the whole, identical from person to person. It is in the small differences brought on by random mutations that all the differences we see between people occur. Many of these differences are a single letter chance in a portion of DNA, a G instead of a C, for example. Fortunately for the companies, these single letter changes are relative easy to detect, and there are now "Snip Chips" that can detect the values of hundreds of thousands of individual SNPs from a single sample at the same time.

"All genetic variation is a result of random mutation," explains Andro Hsu, Science and Policy Liaison for 23andMe. "A lot of SNPs are neutral, in that they don't seem to have any effect on phenotype, which is the physical characteristics of a person. When you have enough of these mutations, and they get spread out to children, then you get a natural set of variation across the population. Over 99.5 percent of the genome is identical between human beings, and it's that last 0.5 percent or so that's different. And SNPs make up a good deal of those differences."