“We are all from the same seed” – Kara Swisher summarizes what she heard from Linda Avey, co-founder of web based personal genome service 23andMe in the video interview below. Linda and the other founder Anne Wojcicki just talked about the company’s ancestry, genetic comparison and similarity seeking services, the ones that will technologically turned into a social networking service later based on shared genotypes backed by the genetical connectedness of all people (in this case all 23andMe customers). I called this idea the social networking XY.0 yesterday.
Linda’s thought was the following: “If genetics has the basis to bring people together, rather than differentiate them, that’s gonna be really interesting.” (Thanks Deepak for finding the videos)
In a recent Nature report by talented journalist Erika Check Hayden called So similar, yet so different we can find the following expert opinions on the very same topic that is commercialized and envisioned now by 23andMe (citing lengthy here, emphasis by me): In his 2000 State of the Union Address, President Bill Clinton chose to emphasize something he had recently heard from a genome researcher: that humans are all, irrespective of race, 99.9% the same genetically. “Modern science,” he told his country’s legislators, “has confirmed what ancient faiths have always taught: the most important fact of life is our common humanity.” Seven years on, and four years after the final publication of the sequences from the Human Genome Project, new technologies and larger data sets are allowing genome biologists to answer a conundrum embodied in that unity-inspiring percentage: if our DNA is so similar, why do we seem different in so many ways?
The answer, in part, is that the genome is not as uniform as Clinton was led to believe; nor is it nearly as sedate, stable and homogeneous as scientists used to think. It’s less a ‘Book of Life’, more a wiki; many of its ho-hum elements don’t change, but some really interesting bits are constantly revised.
“Maybe 99% of our genome behaves in a nice, predictable way,” says Gilean McVean, a statistical geneticist at the University of Oxford, UK. “But it’s become clear that there is this pool of errant variants that are responsible for a lot of the dynamism in our genome, and we don’t understand its consequences for disease risk or normal variation.”
Over the past year, two large studies1,2 have found evidence that many people carry around lots of large chunks of DNA that are deleted, copied, flipped or otherwise rearranged in other people. The findings confirm earlier studies that hinted at this type of ‘structural’ variation but were not large enough to command assent3. A study of the genome of sequencing pioneer Craig Venter also found much more variation from reference sequences than expected4.
The larger analyses estimate that such variable regions could make up more than 10% of the genome, vindicating scientists, such as Evan Eichler of the University of Washington in Seattle, who have long argued that structural variation is a major source of diversity. Scientists are still investigating how much it contributes to differences between populations. But it is already clearly linked to some differences between individuals that can be correlated with behaviour or environment. For example, a study published in September reported5 that evolution has driven a starch-digestion gene to duplicate itself in people with traditionally starch-heavy diets.
“We’re getting away from this 0.1% figure that has been in our minds ever since the draft human genome sequence came out,” says Hunt Willard, head of the Institute for Genome Sciences and Policy at Duke University Medical Center in Durham, North Carolina. “We’re now looking at maybe half a per cent of content that is unique to individual genomes.” The actual variation is thus lower than the extent of the variable regions, but larger than previously thought. “Maybe Eichler always had that number in his head,” adds Willard, “but no one else did.”
- Redon, R. et al. Nature 444, 444–454 (2006).
- Stranger, B. E. et al. Science 315, 848–853 (2007).
- Nature 437, 1084–1086 (2005).
- Nature 447, 358–359 (2007).