Researchers in Iceland have recorded the human genetic code of the "entire nation" in the largest ever study of its kind.
It means it is now technically possible to identify every woman at high risk of breast cancer in the country.
The scientists also discovered a score of new gene mutations which, with further study, could shed light on possible future treatments for diseases such as Alzheimer's, gallstones and heart disease.
The study by Decode, a company which has been gathering and studying Icelandic genomes for 18 years, was published in four linked papers yesterday in the Nature Genetics journal.
Decode founder and CEO Dr Kari Stefansson told the BBC: "We could, in Iceland, at the push of a button find all women who carry mutations in the BRCA2 gene."
Hollywood actress Angelina Jolie revealed on Tuesday her decision to have her ovaries and fallopian tubes removed, following her double mastectomy two years ago. A blood test showed she carried a faulty BRCA1 gene, significantly increasing her risk of breast and ovarian cancer.
Stefansson said: "This risk could basically be nullified by preventive mastectomies and ovariectomies. It would be criminal not to take advantage of it and I am convinced that my fellow countrymen will begin to use it pretty soon."
He said Iceland has a uniquely homogenous population, meaning individuals can be regarded as the same 'type' with little genetic variation. This enabled the team to trace the country's lineage to a few common ancestors, making it easier to identify notable gene variants.
The team sequenced the whole genomes, or complete DNA data, of 2,636 Icelanders and used this to accurately deduce the genomes of more than 100,000 others - equal to almost a third of the population. Stefansson says that, "By using these tricks we can predict, with substantial accuracy, the genome of the entire nation."
According to Daniel G. MacArthur, a geneticist at Massachusetts General Hospital who was not involved in the research, the Decode team have gathered "more genetic data on a much larger chunk of the population than in any other country in the world."
Jason Bobe, executive director of Personal Genomes (a project dedicated to creating public genome, health, and trait data) and director of the Sharing Lab at the Icahn Institute at Mt. Sinai, says the project is an "impressive effort".
"It is clear that sequencing the DNA of entire populations will increasingly be the easy part," he says. "The real challenges ahead will be engaging people and their healthcare providers with this information in ways that improve health."
Jon Baines, chairman of NADPO (the National Association of Data Protection and Freedom of Information Officers) says the project offers up some "profound, and profoundly troubling" issues.
"Legally and ethically, using people's sensitive medical data for different purposes and without their consent is highly questionable," he says.
Currently, the data recorded is anonymous. But Baines points out that under European data protection law, data is only anonymous if individuals cannot be identified, raising questions about the purported anonymisation techniques used in the first place.
"If it is made public or used commercially, and individuals could be identified, it seems to me it would be a major contravention of data protection law and of medical confidentiality," he says.
However, he acknowledges that the power to predict the likelihood of diseases and take preventative action could be enormously beneficial.
"As a society we need to have an open and frank debate about what we want our personal data to be used for, and what part we can play in that," he says.
Uncommon Knowledge
Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
