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Ancestry DNA Test Results Are Not Only Widely Misinterpreted, They’re Potentially Damaging

Companies like 23andMe are inadvertently convincing people that concepts as complicated as race or ethnicity are written in your genes — these, say experts, are ‘very dangerous ideas’

“A Serious Ethnic Mix: Australian Ali Clemesha thought she knew her ethnic background,” says a case-study teaser next to a picture of a grinning blonde person on the landing page for Ancestry.com’s consumer DNA testing service. “But her DNA results revealed so much more with some exotic surprises.” Next to another smiling customer, this time Hispanic-looking with head cocked as if mid-“Hmm” moment, runs the caption: “Connected Beyond Colombia: Isabel Rojas always identified with her Bogotá roots. But her DNA results took her ancestry to unexpected places.”

Now, I’m no marketing professional, and I have zero experience working in the burgeoning genealogical genetics sector, but may I humbly offer another option to help entice people who are feeling curious about their ancestry? “Take What’s Mine: Seattle businessman Ralph Taylor lived as a white man until a DNA test in 2010 revealed he was 4 percent sub-Saharan African — he believed this entitled him to minority-business certification so his company could land more contracts in the transportation industry. The State of Washington disagreed. Now he’s suing the government!”

Here’s another, much more visible version: “Minority Opinion: Massachusetts elected official Elizabeth Warren was under fire for declaring she had a Native American element in her family history — up until October last year when she used a DNA test to back up her claims with scientific evidence… and now everyone’s more upset with her than ever!”

As Senator Warren is now fully appreciating, the lure of hard evidence that promises to clear up annoying fuzziness around the edges of your ethnic or racial identity can be a blind alley. Genetics’ claim to adjudicate on our ancestry has become popular just at the point when debates over cultural appropriation, and what does and doesn’t count when it comes to identity, are raging at fever pitch.

All that came rather too easily: Who knows, maybe deep down I really am a marketing professional in the burgeoning ancestry sector? I should send off for a DNA test to find out!

That said, most of us aren’t interested in making public proclamations about our pedigree. Aside from the risk of uncovering a bombshell about your immediate family (and more and more cases of sibling/paternity/maternity shock seem to be popping into view), when it comes to resolving the big “Who Am I?” that seems to hover over all our lives to some degree or other, can there be much harm in privately finding out a little more about ourselves? Even just for a bit of a giggle or something interesting to say at parties?

“For the same reason that many, many people are interested in genealogy,” says Wendy Roth, associate professor of sociology at the University of British Columbia, DNA tests “seem to offer a way to connect with the individual’s location in this big, messy world — and that’s appealing to many people.” As a sociologist, Roth had always seen race as an abstract idea that was imposed on us by society, and not something that had a basis in genetic reality. “So when I heard about these tests that purported to tell you about your race or ethnicity,” she says — noting that in the mid-2000s, the ads were still using the words “race” and “ethnicity” explicitly; they don’t any more —“I thought, these tests are misleading people, or telling people something that genes can’t actually tell them. This must be a scam.”

Her boyfriend at the time (now husband), however, was a graduate biology student, who assured her the science behind DNA ancestry testing was legitimate, and as people submitted their samples to the industry’s data pool, its findings were becoming more and more refined.  

After extensive research into the impact of consumer genetic tests on how people shape their identities, Roth has come to the conclusion that “population genetics is sound as a science. But it’s only meant to answer questions at a population level — groups, writ large: Where did groups move? And what are the population migrations over time?” When marketed to consumers, she thinks, the business model is inherently misleading. In trying to reverse its God’s-eye perspective to make a sale, the methodology is brought “down to answer questions at an individual level — and that’s where the problem is. The science can’t really be used to answer definitive questions about a single individual.”

‘Creative Science’

The urge to dig for treasure in our genome is a strong one, as evidenced by the meteoric rise of commercial DNA-testing services such as 23andMe, Helix and MyHeritage, as well as Ancestry.com. Genealogy is said to be one of America’s most popular hobbies (eclipsed only by gardening and porn, apparently), and according to M.I.T. Technology Review, the number of people buying at-home DNA-testing kits more than doubled in both 2017 and 2018. This growth has swollen the industry’s combined genetic database from around 12 million people to an estimated total of 26 million in the past two years. Since its beginnings in the early 2000s, the consumer genetic-testing market has grown to be worth more than $360 million in 2017, and that figure is expected rise to $928 million by 2023.

Part of the attraction is the simplicity of the package: For $99, 23andMe will process a dollop of your spit, then spit your genetically weighted ethnic makeup right back at you (having first spent a few weeks analyzing between 500,000 and 1 million “single nucleotide polymorphisms” — the occasional variants, amid the 3 billion or so base pairs of chemical compounds that structure DNA and in sum make up your genome — and then comparing these genetic markers, also known as “alleles,” against the millions of samples in its database gathered from various ethnic, geographic and historical populations. See? Simple). Your results are presented as easy-to-parse percentage scores, given to one decimal place (46.3 percent Middle Eastern, for example, or 32.1 percent sub-Saharan African), suggesting a high degree of precision in the calculations.

Many people, though, says Roth, “make the mistake of thinking that the percentages they receive in an admixture test report are accurate and that this indicates what they actually are.” Interpreting the readout as a definitive statement, they fail to appreciate that the companies’ conclusions are all ultimately based on probability rather than absolute mathematical baselines.

Alexander Platt, a geneticist who studies population structure at Temple University, Philadelphia, explains why: “There are plenty of places in the genome — usually there’s one about every thousand base pairs — where not everybody has the same nucleotide.” (A nucleotide being the basic unit of DNA’s structure, which encompasses each base pair and its bonding “rung” on the double-helix ladder.) “And some of these variants, these alleles, are more common in some parts of the world than elsewhere.”

The way the companies define their regional and ethnic archetypes, then, necessarily contains a certain degree of arbitrariness. They map recurring genetic patterns on to the regions of the world where they’re seen to cluster, and then infer ethnic groupings from those distributions, based on what’s known about human migration and settlement patterns throughout history. “When a company tells you your ancestry is 20 percent Italian and 40 percent Hungarian,” explains Platt, “what it’s really saying is: ‘Your ancestry looks similar to that of people who live in these places and claim that their ancestry is from these places.’”

By now though, the data sets for populations in many parts of the world are massive, and for geneticists, greater scale equates to higher and higher resolutions when comparing alleles between groups. For many test-takers, this should aggregate to a fairly high degree of confidence in the results, says Platt. But it’s never going to be fully conclusive — especially, says Roth, when you consider that “even if they find that a particular marker is most likely to be associated with Scandinavia, for example, that marker is also found in other populations aside from Scandinavians. So it’s a probability that that marker indicates Scandinavian ancestry as opposed to some other ancestry.”

Before you take those odds and run off to join your local Viking longboat crew, there are yet more caveat emptors that might be clouding your test results further. Thanks to historical factors that have shaped certain groups over centuries — such as their geographical isolation (the Finnish, for example), or a strongly ingrained sense of culture (as with Ashkenazi Jews) — ancestry companies can be more certain when matches to these well-characterized groups show up. But where this isn’t the case, such as in the polyglot patchworks of East Asia and Western Europe, definitive genetic patterns are harder to discern.

For other parts of the world, it’s a lack of data that’s the problem. Frustratingly for anyone interrogating their African lineage, this has been the case for data sets across the African continent — this despite the fact that Africa contains the richest source of human genetic diversity on Earth (due to a “genetic bottleneck,” which occurred some 50,000 to 60,000 years ago when people ventured beyond our home continent), and would otherwise be ideal for this kind of population tracking. There has been far more data amassed for non-African humans, laments Platt, which means for populations outside of Africa, “even though the differences amongst individuals are smaller, they have been much better characterized, so much finer resolution is available.”

Inevitably, because we’re in the realm of statistics and Big Data, we are also at the mercy of insensitive, ungentle algorithms. “In setting up the algorithms that make the calls [on how ethnicities and regional groups are to be defined], there are decisions that have to be made, some borders that have to be set,” says Platt, “and there are always places in there where the people setting up the system may or may not have known what results these decisions would have.”

Illustrating how the businesses permit scope for your classic, “Guys, what if we just…?” type of judgement calls, he cites the example of 23andMe, which recently updated its taxonomies to “recategorize what Ashkenazi Jewish ancestry looks like.” He explains, “Most people who were mostly Ashkenazi Jewish, or would tell you they were Ashkenazi Jews, were coming back with results that said around 90 percent.” At some point, apparently, the population modelers decided it was a safe bet to bundle in that few percent remainder too. “If people who will tell you they’re Ashkenazi Jewish are coming back with these other things fairly reliably,” runs Platt’s hypothesis on what led to this, “maybe it lines up better with people’s understanding of the term ‘ancestry’ to just say, yes, this is Ashkenazi Jewish ancestry.” It’s this kind of “creative science,” as he terms it, that leads the various DNA-testing services to take slightly different approaches in their definitions and number-crunching methodologies — that’s why it’s often been found that separate companies will return awkwardly divergent results when presented with samples from the same person.

Ethnicity à la Carte

The genetic tapestries that structure populations, it’s clear, are vastly complicated and complicatedly vast. And as needy, naïve individuals with limited statistical fields of vision, we consumers are prone to making all sorts of unfounded assumptions about them. What’s worse is that the DNA might provide us with the lat-long coordinates to pinpoint our place in the species — but when we attempt to map those on to something as emotionally fragile and mercurial as our self-image, we’re immediately at risk of getting hopelessly lost all over again.

In a study published in the American Journal of Sociology in July 2018, Roth found that while most people who took a commercial genetic ancestry test raised an eyebrow, absorbed what it told them and got on with their lives, 36 percent of the test-takers she interviewed chose to adapt their race or ethnicity in the light of their results. This impulse was stronger among the interviewees who before the test identified only as “white American” — around half of them saw a reason to change this afterwards.

“Many of the white test-takers that I spoke with were several generations removed from having emigrated to North America,” explains Roth. “They had kind of a general European identity, but they might not have known exactly where in Europe their families came from. So they felt that their ethnic identity was boring. They felt like they were just like everybody else, they weren’t distinctive, they didn’t have any connection to any traditions or customs. It may very well be that for many people there’s a kind of exoticism, particularly around non-European identity, that they found exciting, for better or worse.”

Another explanation Roth puts forward for what might be leading white Americans in particular to “cherry-pick” new racial or ethnic aspects from their genome to identify with, is that “Some of them might have had a bit of guilt — white guilt about being privileged in society. And being able to claim a non-European identity might have helped them deal with some of that guilt. Or at least ignore it.”

In contrast, the non-white respondents in her study were less likely to remold their identities because “they had very strong political and cultural connections to their group identity. So African-Americans felt that it would be in some ways a betrayal of their group to give up their identity.” Among African-Americans and Latinos, she also found a greater receptiveness to the idea of mixed genetic heritage in general, which she believes is down to their communities’ natural inclusion of people with mixed racial backgrounds. For subjects from these groups, then, seeing new and unfamiliar elements in their genetic readouts, “didn’t really come as a surprise to them, and it didn’t challenge what it meant to identify as African-American or Latino.”

“A lot of it has to do with being in the minority in a society,” says Roth, pointing to a theory in psychology known as optimal distinctiveness. “You want to be unique, but also have a community to belong to. The ideal-sized group that you want to belong to is usually a minority group in a society; if you’re part of the majority you might feel like you’re not distinctive enough, and that’s what a lot of the white respondents were feeling.”

What’s the Difference?

The quest for answers about who we are might seem benign. Whether it’s to satisfy a frivolous urge to spice up a bland self-image, whether it’s to give ourselves permission to wear a kilt at a wedding or whether it’s to confront the big questions that weigh on our minds about our ancestors’ experiences — of slavery, perhaps, or of the Holocaust — it’s a personal journey that surely needn’t concern anyone else. Except, says Roth, if we’re all beginning to redefine race and ethnicity in terms of genetic, as opposed to social, properties, we’re opening the door to trouble for society.

Her worry is that DNA testing promotes a “genetically essentialist” view of race and ethnicity — that these abstract concepts, morphed into “something determined biologically,” will now be taken to have concrete implications across the board “for your skills, your traits and your behavior. Those are very dangerous ideas,” she warns. “They have led to eugenics movements and apartheid and the Holocaust — basically a belief that races are inherently inferior or superior, and there’s a very strong concern that these tests are going to reinforce that belief.”

Although, in her recent, as yet unpublished, work, she has found evidence that for some people, the opposite tendency is true — that when confronted with a mixed genetic heritage, at least some people “come away realizing, ‘Hey, we’re all the same! We’re all related.’” But, she says, “If anyone is coming away thinking that races are essentially different, that’s a problem.”

As geneticist Platt points out, the fact is that genetically we are virtually all the same. “Ancestry is very much a social construct,” he says. While he sees genetic markers as useful on the whole, as a reliable set of signposts to where on the planet our origins lie — since “any one of us tends to have a majority of our ancestors from a particular geographic region” — nevertheless “there aren’t that many genetic differences between people with ancestries from different regions. So genetically we’re a very homogeneous species.”

The problem is that the temptation to categorize people in easy, simplistic ways is all bound up with why we have such a deep desire to forge identities in the first place. When you get right down to it, why does it feel so important that we find definitive answers regarding the regions, races and cultures our forebears inhabited? “In every society there’s a tendency to identify with your in-group and to feel a sense of support, connection and strength that comes from a strong in-group identity,” suggests Roth. “How the in-group versus the out-group gets defined is different across societies. So in the British Isles it might be whether you’re from England versus Scotland versus Ireland; in the former Yugoslavia it might be regional; in some places it might be religion. People build strong in-group identities with many of these different aspects of themselves — so it’s not just race or ethnicity that’s all-important, they also have strong religious identities and gender identities and national identities. If you could get a genetic test that proclaimed your religious identity, I’m sure that would be of interest to many people too, but this is a particular phenomenon that seems to be able to tell people something about where their family was in history.”

When you make that discovery via a DNA test, often it seems the reality both is and isn’t what you want it to be: The information you’ll glean is much glossier but also much emptier than the humanizing and historical context that comes with traditional paper-trail genealogy. Spitting in a tube feels like a less arduous route to self-knowledge, though — even for those who understand the complexity lurking behind the percentage pie charts. “I have done it,” says Platt, adding that it was mostly because his wife wanted to. “My own ancestry is Ashkenazi Jewish; I would have been shocked to see any other results and was not shocked when that was not the case. It read 96 percent, and the other few percent was stuff that I thought made sense for getting in there at some point. I was not concerned that I needed to go track down a few percent of rogue ancestors.”

As for me, my results have come back too, and it turns out I’m: 38.9 percent jobbing journalist; 2.7 percent marketing professional in the burgeoning genetic ancestry industry (knew it!); 45.2 percent father of boys who should be able to tie their own shoes by now; 44.5 percent married to a New Zealander; 88.8 percent exhausted 66.6 percent of the time; still only 38 percent of the way through Game of Thrones; 25 percent lying if I said I wasn’t a little intrigued by the idea of getting my own ancestry DNA test done; but 75 percent sure I can find something far more worthwhile to spend that $99 on.