Australasian Science: Australia's authority on science since 1938

Genetic Ancestry

By Michael Cook

The thriving business of DNA ancestry testing is hawking dreams, not science.

23andMe.com, a California-based genetic testing company, spruiks ancestry testing on its website. For US$99 you can discover the composition of your ancestors, your genetic relatives, your maternal and paternal lineages, and even the percentage of your DNA that comes from Neanderthals.

“Trace Your Family Lineages Back 10,000 Years and Beyond,” it says. “Find out if you share an ancestor with famous figures such as Marie Antoinette and Thomas Jefferson.”

Similar companies are springing up everywhere – to the enrichment of some geneticists and the dismay of others. Five years ago three US scientists described ancestry tests in the New England Journal of Medicine as “premature attempts at popularising genetic testing”. One of them called the tests “recreational genomics”.

Even more huffy was a British geneticist, Dr Mark Thomas of University College London, who wrote in The Guardian recently that most of these claims were better described as “genetic astrology”. All that tests can establish is a statistical probability of my lineage. Just because I share a certain genetic marker with residents of a certain area does not mean that my ancestors came from there.

Nor is the fact that Napoleon and I may share a marker meaningful. One study published in Nature in 2004 estimated that the most recent common ancestor of everyone alive today lived only about 4000 years ago. Human migration has spread genes across the globe.

However, a public bewitched by genetic determinism ignores disclaimers and believes that ancestry tests constitute rigorous scientific proof. This is dangerous.

Who we are is a fundamental dimension of human experience. Anyone who claims to have special insight ought to have a special sense of responsibility. This suggests that some weighty ethical questions must be asked about these tests.

Do the tests reinforce discredited stereotypes about race? The notion of “race” still has profound social, political, personal and economic implications. Ancestry tests tend to confirm the ancient prejudice that the colour of our skin is more important than our cultural and social background, even though there are no fixed racial characteristics.

This may not be an issue in Australia at the moment, but it is in other countries. In Hungary, a genetic testing company recently issued a certificate of “racial purity” to a politician in the far-right Jobbik Party stating that he had no Jewish or Romany blood.

Will the tests be exploited for political gain? Ancestor testing is being used for weightier matters than seeing whether you are related to Charlemagne or Genghis Khan. In the United States, Native American tribes have tried to use genetic tests to check whether people are really members of the tribe. A lot is at stake, as there may be special government benefits for housing, education and health care. Many tribes have built casinos on their reservations and members could be eligible for a share of the profits.

Do the tests give unwarranted certainty about personal identity? Many companies marketing genetic ancestry tests are selling dreams, not genealogy. A British company whose work was featured recently on the BBC says on its website: “There are stories only DNA can tell. And sometimes these can be startling, changing perceptions of our own identity, making connections we never dreamed of.” But surely it is unethical to startle people unless information is certain?

These companies are mining a rich vein of anxiety in contemporary culture. In nations like the United States or Australia, where most of the population is descended from immigrants from distant continents, some people already feel uprooted and dislocated. Furthermore, many of our contemporaries have been cut off from their past through adoption, IVF, anonymous donor insemination and divorce.

At best, ancestry testing gives them a reassuring sketch of their missing forebears, but far too often it is just a Rohrsach blot in which customers project their own visions of the misty past. It is not the truth.

“Perhaps it is harmless fun to speculate beyond the facts, armed with exciting new DNA technologies?” Thomas asks rhetorically. “Not really. It costs unwitting customers of the genetic ancestry industry a substantial amount of hard-earned cash, and it disillusions them about science and scientists when they learn the truth, which is almost always disappointing relative to the story they were told.”

Michael Cook is editor of the online bioethics newsletter BioEdge.