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

The Government of Alberta identified 115 new COVID-19 cases Sunday, bringing the provincial total to 3,089.
(Black Press file photo)
Red Deer COVID cases continue to fall

114 cases in Red Deer, down one from Saturday

File Photo
Blackfalds RCMP seeking suspects in traffic collision

RCMP are asking the public for help identifing two suspects wanted for multiple offences

Maskwacis Pride crosswalk (Left to right): Montana First Nation Councillor Reggie Rabbit, Samson Cree Nation Councillor Louise Omeasoo, Samson Cree Nation Councillor Katherine Swampy, Samson Cree Nation Councillor Shannon Buffalo, Samson Cree Nation Chief Vern Saddleback.
Pride in Maskwacis

The 4th inaugural Maskwacis Pride crosswalk painting took place on Saturday 12, 2020.

Alberta Premier Jason Kenney arrives at the 2021 budget in Edmonton on Thursday, Feb. 25, 2021.THE CANADIAN PRESS/Jason Franson
Alberta launches COVID vaccine lottery with million-dollar prizes to encourage uptake

The premier says the lottery will offer three prizes worth $1 million a piece, as well as other prizes

The City of Red Deer sits at 249 active cases of the virus, after hitting a peak of 565 active cases on Feb. 22. (Black Press file image)
Red Deer down to 119 active COVID-19 cases

Province identifies 179 new cases Saturday

Canadian Prime Minister Justin Trudeau participates in a plenary session at the G7 Summit in Carbis Bay, England on Friday June 11, 2021. THE CANADIAN PRESS/Adrian Wyld
Canada donating 13M surplus COVID-19 vaccine doses to poor countries

Trudeau says the government will pay for 87 million shots to be distributed to poor countries

Montreal Canadiens goaltender Carey Price (31) is scored on by Vegas Golden Knights defenseman Alec Martinez, not pictured, during the second period in Game 1 of an NHL hockey Stanley Cup semifinal playoff series Monday, June 14, 2021, in Las Vegas. (AP Photo/John Locher)
Habs fall 4-1 to Vegas Golden Knights in Game 1 of NHL semifinal series

Match was Montreal’s first game outside of Canada in 2021

The Kamloops Indian Residential School is photographed using a drone in Kamloops, B.C., Monday, June, 14, 2021. The remains of 215 children were discovered buried near the former school earlier this month. THE CANADIAN PRESS/Jonathan Hayward
Communities grapple with what to do with former residential and day schools

Some tear them down as a tool to help healing, others repurpose them as tools for moving forward

RCMP Const. Shelby Patton is shown in this undated handout photo. RCMP say that Patton was hit by an allegedly stolen truck that he had pulled over on Saturday morning in Wolseley, east of Regina. THE CANADIAN PRESS/HO, RCMP
Pair charged in Saskatchewan Mountie’s death make first court appearance

Const. Shelby Patton was hit by an allegedly stolen truck that he had pulled over Saturday morning

David and Collet Stephan leave for a break during an appeal hearing in Calgary on Thursday, March 9, 2017. THE CANADIAN PRESS/Todd Korol
Appeal Court rejects stay for Alberta couple facing third trial in son’s death

Pair accused in their earlier trials of not seeking medical attention for their son sooner

Calgary Stampeders’ Jerome Messam leaps over a tackle during second half CFL western semifinal football action in Calgary, Sunday, Nov. 15, 2015.THE CANADIAN PRESS/Jeff McIntosh
CFL football will be played this summer in Canada

Governors vote unanimously in favour to start the ‘21 campaign on Aug. 5

Citizenship Minister Marco Mendicino holds a press conference in Ottawa on Thursday, Nov. 12, 2020. The federal government is announcing that Indigenous people can now apply to reclaim their names on passports and other government documents. THE CANADIAN PRESS/Sean Kilpatrick
Indigenous people can now reclaim traditional names on their passports and other ID

Announcement applies to all individuals of First Nations, Inuit and Métis background

This undated photo provided by Girl Scouts of New Mexico Trails shows a scout donating cookies to firefighters in Rio Rancho, New Mexico, as part of the Hometown Heroes program. As the coronavirus pandemic wore into the spring selling season, many Girl Scout troops nixed their traditional cookie booths for safety reasons. That resulted in millions of boxes of unsold cookies. (Girl Scouts of New Mexico Trails via AP)
Thinner Mints: Girl Scouts have millions of unsold cookies

Since majority of cookies are sold in-person, pandemic made the shortfall expected

In this artist’s sketch, Nathaniel Veltman makes a video court appearance in London, Ont., on June 10, 2021 as Justice of the Peace Robert Seneshen (top left) and lawyer Alayna Jay look on. THE CANADIAN PRESS/Alexandra Newbould
Terror charges laid against London attack suspect

Crown says Nathaniel Veltman’s four counts of first-degree murder constitute an act of terrorism

Most Read