An example of a DNA collection test used at Any Lab Test Now on Friday, July 20, 2018 in Everett, Wa. (Olivia Vanni / The Herald)

An example of a DNA collection test used at Any Lab Test Now on Friday, July 20, 2018 in Everett, Wa. (Olivia Vanni / The Herald)

DNA tests make fun holiday gifts, but beware of the hype

Whether interested in your health or your ancestors, it is important to understand how these tests work

You’ve likely heard about direct-to-consumer DNA testing kits. In the past few years, at-home genetic testing has been featured in the lyrics of chart-topping songs, and has helped police solve decades-old cold cases, including identifying the Golden State Killer in California.

Even if you don’t find a DNA testing kit under your own Christmas tree, there’s a good chance someone you know will.

Whether you’re motivated to learn about your health or where your ancestors came from, it is important to understand how these tests work — before you spit in the tube.

While exciting, there are things that these genetic testing kits cannot tell users — and important personal implications that consumers should consider.

Health, traits and ancestry kits

My main area of research is around clinical genome sequencing, where we look through all of a person’s DNA to help diagnose diseases. With a PhD in genetics, I often get questions from friends and family about which direct-to-consumer genetic test they should buy, or requests to discuss results. Most questions are about two types of products: ancestry and health kits.

The most popular ancestry kit is from AncestryDNA. These kits are aimed at giving users insight into where their ancestors might be from. They can also connect users with family members who have used the service and have opted into having their information shared. Another option is Living DNA, which has a smaller dataset but provides more precise information on the U.K. and Ireland.

The most popular health kit is from 23andMe. Depending on the user’s preference, results include information on predispositions for diseases such as diabetes and Alzheimer’s, as well as on the likelihood of having certain traits such as hair colour and taste. This company also offers ancestry analysis, as well as ancestry and trait-only kits that don’t provide health information. The kit offered by the newer MyHeritage DNA also provides a combined ancestry and health option.

There are other kits out there claiming to evaluate everything from athletic potential to relationship compatibility. But gift-buyers beware: for most of these, in contrast to those above, the evidence is seriously lacking.

How these tests work

For all of these tests, customers receive a kit in the mail. The kits contain instructions for collecting a saliva sample, which you mail back to the company for analysis.

During this analysis, these popular tests do not look at the entire genome. Instead, they employ single nucleotide polymorphism (SNP) genotyping. As humans we all share 99.9 per cent of our DNA. SNPs are essentially what is left: all of the points at which we can differ from our neighbour, making us unique. SNP genotyping looks at a subset of these sites to “survey” the user’s genome.

These SNPs are then compared to reference datasets of individuals with known conditions or ancestry. Most results are based on the SNPs shared with a given group. For example, if your results say that you are 42 per cent Southeast Asian, it’s because 42 per cent of your SNPs were most likely to have come from a group in the reference dataset labelled “Southeast Asian.” The same goes for traits and health conditions.

How they differ from clinical tests

Direct-to-consumer genetic tests are not a substitute for clinical assessment. The methods used differ dramatically from what is done to diagnose genetic diseases.

In a clinical setting, when suspicion of a genetic condition is high, entire genes are often analyzed. These are genes where we understand how changes in the DNA cause cellular changes that can cause the disease. Furthermore, clinical assessment includes genetic counselling that is often key to understanding results.

In contrast, findings from direct-to-consumer genetic tests are often just statistical links; there is commonly no direct disease-causing effect from the SNPs.

Users may interpret a result as positive, when the risk increase is only minimal, or entirely false. These tests can also give false reassurance because they do not sequence genes in their entirety and can miss potentially harmful variants.

Before you spit in a tube, stop and think

These tests are exciting: they introduce new audiences to genetics and get people thinking about their health. They’re also helping to build vast genetic databases from which medical research will be conducted.

But for individual users, there are important caveats to consider. Recent reports have questioned the accuracy of these tests: identical twins can receive different results. Furthermore, a lack of diversity in the reference data has caused particular concern regarding accuracy of results for ethnic minorities.

There are also concerns about the way these tests emphasize racial categories that science considers to be social constructs and biologically meaningless.

Professor Tim Caulfield shares concerns about the way race is presented in the marketing of DNA tests.

A recent paper in the British Medical Journal suggests four helpful questions for users to consider. First, users should ask themselves why they want the test. If it is to answer a medical question, then they should speak with their doctor. Users should also think about how they might feel when they receive results containing information they would rather not know.

Users should also consider issues around security and privacy. It is important to read the fine print of the service you’re using, and determine whether you’re comfortable sharing personal information, now and in the future.

In Canada, policies around genetics have not always kept up with the science. At present, direct-to-consumer genetic testing is unregulated. And, although Canadians have legislative protections against genetic discrimination, those laws are being challenged in the courts, and could change.

Finally, it may also be worth discussing DNA testing with relatives. We share half of our genome with our immediate family members, and smaller fractions with more distant relatives. Genetic results not only affect us, but our family.

Bottom line: It’s all for fun

Some users may feel they learn more about themselves. For others, results may bring people closer together — not a bad outcome for the holiday season.

At the end of the day, these genetic testing kits are for entertainment: they should not be used to assess health risk in any meaningful way.

If you have any questions related to your health or a genetic disease, discuss these with your family doctor or a suitable health-care professional.

Michael Mackley, Junior Fellow, MacEachen Institute for Public Policy and Governance; Medical Student, Dalhousie University , The Canadian Press

Like us on Facebook and follow us on Twitter.

Just Posted

Harrison Hot Springs country singer Todd Richard poses for a photo with Mission firefighters. (Photo/Sarah Plawutski)
VIDEO: Harrison country artist Todd Richard plans for a busy, rockin’ summer

Richard and his band look to live shows as restrictions start to lift

Woody’s RV World hosts a grand opening for its brand-new Abbotsford location on Saturday. (YouTube)
Woody’s RV World hosts Abbotsford grand opening on Saturday

First-ever B.C. location for successful RV chain, located on Marshall Road

A t-shirt designed by Coast Salish artist Bonny Graham (B. Wyse) includes the phrase ‘every child matters’ in a custom font inspired by Coast Salish design.
Chilliwack FC works with Stó:lō Nation Chiefs Council on t-shirt fundraiser

The youth soccer organization will sell custom-designed orange shirts, donating proceeds to the SNCC

Wilma’s Transition House Charity Golf Tournament takes place Aug. 21, 2021.
Buzz building for 2021 Wilma’s Transition House Charity Golf Tournament

The key fundraiser for the non-profit will be held Aug. 21 at the Cultus Lake Golf Course

Special weather statement issued for Fraser Valley as first summer heat arrives June 20, 2021, and set to persist all week. (Photo by James Day on Unsplash)
Second day of hot temperatures rippling across Fraser Valley

Communities from Abbotsford to Hope will see daytime high maximum temps of 32 degrees

Marco Mendicino, Minister of Immigration, Refugees and Citizenship during a press conference in Ottawa on Thursday, May 13, 2021. THE CANADIAN PRESS/Sean Kilpatrick
Canada to welcome 45,000 refugees this year, says immigration minister

Canada plans to increase persons admitted from 23,500 to 45,000 and expedite permanent residency applications

The Sacred Hearts church on PIB land burned Monday morning. (Theresa May Jack/Facebook)
Two churches on First Nation land in South Okanagan burn to the ground

Sacred Hearts church on Penticton Indian Band land was reduced to rubble

Tl’etinqox-lead ceremony at the site of the former St. Joseph’s Mission in Williams Lake, B.C., June 18, 2021. (Angie Mindus photo - Williams Lake Tribune)
‘We are all one people’: Honouring residential school victims and survivors

Love, support and curiousity: Canadians urged to learn about residential schools and their impact

Indigenous rights and climate activists gathered outside Liberty Mutual’s office in Vancouver to pressure the insurance giant to stop covering Trans Mountain. (Photo by Andrew Larigakis)
Activists work to ensure Trans Mountain won’t get insurance

Global campaign urging insurance providers to stay away from Canadian pipeline project

In the first election with public money replacing corporate or union donations, B.C. Liberal leader Andrew Wilkinson, B.C. Greens leader Sonia Furstenau and B.C. NDP leader John Horgan take part in election debate at the University of B.C., Oct. 13, 2020. (THE CANADIAN PRESS)
B.C. MLAs ponder 2022 ‘sunset’ of subsidy for political parties

NDP, B.C. Fed call for increase, B.C. Liberals have no comment

Emergency crews shut down White Rock’s Five Corners district on Feb. 19, 2020 following an assault. (File photo)
Trial underway in February 2020 death of White Rock senior

Ross Banner charged with manslaughter following Five Corners altercation

Investigators use a bucket to help recover human remains at a home burned in the Camp fire, Thursday, Nov. 15, 2018, in Magalia, Calif. Many of the missing in the deadly Northern California wildfire are elderly residents in Magalia, a forested town of about 11,000 north of the destroyed town of Paradise. (AP Photo/John Locher)
‘Forever War’ with fire has California battling forests instead

Five of the state’s largest-ever blazes seared California last year, as authorities tackle prevention

Tokyo 2020 President Seiko Hashimoto and IOC President Thomas Bach, on a screen, speak during a five=party online meeting at Harumi Island Triton Square Tower Y in Tokyo Monday, June 21, 2021. The Tokyo Olympics will allow some local fans to attend when the games open in just over a month, Tokyo organizing committee officials and the IOC said on Monday. (Rodrigo Reyes Marin/Pool Photo via AP)
Tokyo Olympics to allow Japanese fans only, with strict limits

Organizers set a limit of 50% capacity — up to a maximum of 10,000 fans

Most Read