DNA of 'an entire nation' assessed
The genetic code of "an entire nation" has effectively been deduced, say researchers in Iceland, the BBC reports.
The feat was performed by combining DNA data with family trees.
The team say they could now find every woman at high-risk of breast cancer "at the touch of a button" and it would be "criminal" not to use the information.
The reports, published in the journal Nature Genetics, used the data to make a suite of discoveries including the age of the last common ancestor of men.
DNA is passed from one generation to the next. If you knew everything about the DNA of a child and their grandparents, you could figure out a lot about about the DNA of the parents too.
The deCODE genetics team has taken the whole genome sequence of 10,000 people and combined it with nation-wide family trees.
"By using these tricks we can predict, with substantial accuracy, the genome of the entire nation," the chief executive of deCODE, Dr Kari Stefansson told the BBC News website.
Mutations in the BRCA genes lead to a much higher lifetime risk of cancer and led the Hollywood actress Angelina Jolie to have her breasts and ovaries removed.
Dr Stefansson argued: "We could, in Iceland, at the push of a button find all women who carry mutations in the BRCA2 gene.
"This risk could basically be nullified by preventative 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."
The data is all anonymous at the moment. Using such data in medicine would raise ethical issues, including identifying deadly disease genes in people who never volunteered their own DNA for study.
Dr Stefansson says there is a lot of debate still to come "but I'm just an old-fashioned physician, my gut instinct is simply to go to these people and warn them."
He is already in discussions with the Icelandic healthcare system.