Outlandish claims about what we can learn about ourselves from our DNA threaten the credibility of the personal genomics
The personal treasure trove of information in each person’s DNA has for millennia been hidden, tucked away inside each and every cell. Deciphering our genes used to be reserved for high-powered researchers with vastly expensive machines churning out obscure conclusions. The bill for sequencing a person’s entire genome – 21,000 or so human genes – ran to £3bn a decade ago. But plunging costs have spurred a revolution in what’s known as personal genomics.
For just a tiny fraction of that – £100 – any of us can spit into a test tube, send our gene sample off to a direct-to-consumer company for analysis, and receive within days a summary of our ancestral family history, behavioural proclivities and health vulnerabilities. Just as we all have a blood type, we also all have a genotype that has a powerful bearing on our overall health and traits.
On the positive side, the personal genomics revolution has brought science to the masses. It threatens entrenched interests, pitting the regulatory and medical establishment against DNA entrepreneurs, with ageing physicians and bureaucrats lining up against newly minted PhDs, MDs and CEOs. But wholesale changes, as in all revolutions, are messy, with conflicting promises and quality control issues stirring many ethical and medical-related concerns.
Consider the brouhaha over the life and times of Eddie Izzard’s DNA. In the spring of 2013, Izzard, one of the UK’s foremost stand-up comedians, became the poster boy for much that is intriguing and troubling about the personal genomics revolution when he was featured on a BBC programme tracking his family roots.
Titled Meet The Izzards, the programme seemed innocuous enough. He embarked on an epic journey based on the DNA that he inherited to retrace the route of his family’s 10,000-generation journey from Africa to Britain.
According to Jim Wilson, chief scientist at BritainsDNA, a direct-to-consumer genetics company that helped produce the programme, Izzard’s fatherline marks him as a descendant of Anglo-Saxons while his female lineage shows he is a long-lost Viking. Wilson also told Izzard that he is 2.8% Neanderthal, an extraordinary percentage, he said, that resulted from the interbreeding of Homo sapiens – which became modern humans – and other pre-modern humans tens of thousands of years ago.
Except, maybe not. Pretty much all of us have about that percentage of Neanderthal genes, so that was not news. But the BBC’s genealogical potboiler created stories about Izzard’s personal ancestry that went far beyond the limited information a handful of genes can tell us.
It was entertaining, but it’s little more than “genetic astrology” in the eyes of many mainstream scientists, who are increasingly concerned about the proliferation of companies selling genetic data.
“It’s an approach to reading our genetic history that is easily steered by subjective biases, has never been scientifically shown to work and, in some forms, has been explicitly shown not to work,” says Mark Thomas, professor of evolutionary genetics at University College London.
Today you can buy everything from a detailed family history to an assessment of your chances of becoming a supreme athlete or being struck by a particular medical condition. Dozens of companies around the world say they can recreate your ancestral wanderings and tell you your likelihood of contracting breast cancer for as little as £100. It’s estimated that the global direct-to-consumer genetic testing market is approaching £200m in annual sales, and potential profits are skyrocketing as the costs of data collapse.
While sequencing one’s entire genome can provide crucial genetic and medical information for scientists and doctors, companies selling to consumers often offer something different and far less exact. BritainsDNA and others use a controversial analytical method known as phylogeography. It analyses two parts of the human genome that do not substantially change from generation to generation – the Y chromosome found only in men, and which men inherit from their father, and mitochondrial DNA (mtDNA), which can help us track our maternal line.
One of the pioneers in the consumer genetics field is Oxford Ancestors, founded by Bryan Sykes, professor of human genetics at the University of Oxford and author of numerous bestsellers about how DNA can be used to recreate history, including The Seven Daughters of Eve.
Sykes claimed that he could tell us our ancestral clan mothers, each with a moving tale of struggle and survival in prehistoric Europe. It was fun reading, and his book flew off the shelves, but some reaction in the science community was not as positive. “Such elaborate tales … have little or no scientific backing,” says Martin Richards, professor of archaeogenetics at the University of Huddersfield in the UK.
Richards is a proponent of phylogeography – when it’s done cautiously and backed by data. “By tracking the history of genes back through time, geneticists can indeed begin to reconstruct some of the migrations and expansions of the human species,” he says. “But they have no special insight into ethnicity or identity.”
Thomas is critical of the entire field of phylogeography, which examines only a fraction of an individual’s genome rather than the entire body of our inherited DNA. Humans “move around and fool around,” he says, making ancestral family trees mere guesswork – “more astrology than science”. He says that anyone with a romantic ancestral history – Jewish people, Africans, the Irish, the Welsh and any circumscribed group – are all great target audiences for gene-genie entrepreneurs.
Contrary to the impression given in the Izzard documentary, popular DNA tests cannot tell whether a Brit is primarily of Viking, Anglo-Saxon, Norman, Goth or Celt ancestry. Our Y DNA and mtDNA reveal only two ancestral lines among many thousands that make up an individual, and they are no more meaningful than all the others – they are just the lineages that we can easily and inexpensively analyse.
“Those two lineages represent a rapidly diminishing fraction of your ancestry the further back in time you go,” Thomas says. “It may be the case that your mitochondrial DNA lineage came to Britain with the Vikings – although that would be extremely difficult to demonstrate scientifically – but if true, this would still say very little about your origins.”
“Everybody in the world shares a common ancestor who lived as recently as 3,500 years ago,” Thomas explains. “At this point in history, we all share exactly the same set of ancestors.” Because of intermixing, the lines that a direct-to-consumer genetics company tests for – Y DNA and mtDNA – usually provide a misleading picture of your overall ancestry.
Oprah Winfrey famously claimed that DNA tests showed she was descended from Scots on her mother’s side and Zulu warriors from her father’s lineage. But while she may indeed have Scottish and Zulu ancestors, almost every human alive today shares common ancestral roots with Scots and Zulus if you go back far enough.
The limits of phylogeography did not deter BritainsDNA chief executive Alistair Moffat, a historian, and rector of the University of St Andrews, from claiming in 2012 that his firm had discovered Eve’s grandson. That’s impossible, as Moffat’s company has since acknowledged, as there is no evidence of an identifiable genetic Eve. He also said that nine Britons were directly descended from the Queen of Sheba.
The American Society of Human Genetics has twice issued policy papers calling on genetic-ancestry companies to state clearly the limitations and uncertainties in the information that they sell. In 2013, the British NGO Sense About Science posted scathing comments by independent scientists titled, “We are all ‘related’ to Romans, Vikings, Egyptians & Attila the Hun”. They posted an in-depth guide to the burgeoning field, “Sense About Genetic Ancestry Testing”.
When Mark Thomas and colleague David Balding, professor of statistical genetics at University College London, wrote to scientists at BritainsDNA questioning Moffat’s claims, Moffat’s lawyers threatened Thomas and Balding, demanding they do “not report or state as a matter of undisputed fact that our client’s science is ‘wrong’ or untrue”. A journalist writing on the controversy for the student newspaper at St Andrews University also received libel threats, although suits were never pursued. The incompatibility of legal threats and the scientific process led to the journal Nature to publish an editorial titled “The right to speak out”.
Not all ancestral screening companies have landed themselves in hot water. Houston-based FamilyTreeDNA, the world’s largest genetic genealogy company, and its partner firm Gene By Gene, which focuses on inherited disorders, take a more conservative approach to presenting their results. They also link customers to hundreds of thousands of other people in their database who share certain DNA markers, establishing an interactive genealogy community.
The consumer genetics movement took a huge hit in the US recently when the Food and Drug Administration, which regulates the genetic screening industry, threatened to shut down one of the most prominent companies, 23andMe, claiming it was offering medically unreliable information to consumers.
California-based 23andMe, founded by the wife of Google co-founder Sergey Brin, has established itself over five years as a serious player in the personal genomics field, offering ancestral mapping as well as screening for more than 200 diseases through the mail. Its $99 “personal genome service”, which has been used by half a million people, informs customers about their genetic predisposition to certain diseases. Consumers can access this data without going through a physician.
The FDA expressed concerns laterabout some of the intended uses for the test, including detecting mutations in genes that can signal increased risk for breast cancer, which it said could produce a false positive that “could lead a patient to undergo prophylactic surgery, chemoprevention, intensive screening”, while a false negative could miss an actual risk for the disease. The company has agreed to discontinue its marketing of the kits and is now in negotiations with the FDA in hopes of resolving the concerns.
The FDA’s action may appear overwrought, as no physician would agree to any medical procedure based on a simple genetic test, regardless of what a patient requested. But the dispute does highlight the ethical tightrope these firms are walking.
Techno-libertarian personal genomics advocates view the cease-and-desist order as a huge blow, perhaps critical, to the company and maybe to the entire clinical DNA direct-to-consumer movement. Genetic researchers have viewed 23andMe’s database as a treasure trove of information. The company regularly updates customers on research findings pertinent to test results, pursues suggestions for new tests from its customers (such as sexual orientation) and publishes articles with participants in open access journals.
The ethical and legal debate ignited by the FDA’s unprecedented move speaks to the battle between those who believe in the freedom of companies to innovate on behalf of consumers by using new technologies and those who embrace precautionary regulation to protect consumers from making boneheaded mistakes about their health.
Critics of DNA testing companies have also raised privacy issues, fearing that consumers will be concerned about their loss of privacy as companies could post or disclose data about disease proclivities, which could find their way into the hands of nefarious insurance companies. But legislation, at least in the US, has reassured regulators and customers. And in fact, rather than trying to protect their personal information, people are self-disclosing their DNA secrets, blogging, tweeting, emailing and facebooking their intimate genetic information with abandon.
Home-based DNA testing of ancestry and medical conditions is fast moving into the mainstream as prices plunge, further personalising the genomics revolution. There is considerable potential for good, as consumers are empowered to take ownership of their own health and history. But the landscape is cluttered with legal and ethical potholes.
Jon Entine is a senior fellow at the Center for Health & Risk Communication and STATS (Statistical Assessment Service) at George Mason University.DNA genetics genome pharma