More people took ancestry DNA tests in 2017 than all previous years combined, according to a report published earlier this year in MIT Technology Review.
The number of people who have had their DNA analyzed more than doubled during 2017 and now exceeds 12 million. In January 2018, the industry leader reported that it has tested more than 7 million people, including 2 million during the last four months of 2017.
The sudden rise in popularity of ancestry DNA kits, with prices starting at about $50, could have a significant impact on both the manufacturers that supply these companies and the laboratories that process samples.
Today, most companies in the industry collect samples by cheek swab or vial of saliva. But what are the pros and cons of each method? And how accurate are the results of each?
Collecting DNA: Cheek Swab or Saliva Tube?
Three of the top 5 ancestry DNA companies collect samples by cheek swab (or buccal swab). While saliva samples historically tend to collect more DNA per sample, that collection method is not without its disadvantages.
For example, kits featuring saliva tubes run a higher risk of failing to test properly. Most often, that’s because the customer didn’t collect a large enough sample, typically 1-2 milliliters. According to customers, generating that much saliva can be challenging for the elderly, especially those whose medication may induce dry mouth.
And consumers of all ages can have trouble with the restriction on eating or drinking for a period before you collect your sample.
And if you fail the test? You’ll need to buy another kit and try again.
Sample collection from swabbing, on the other hand, offers a number of benefits.
Here are 5 reasons to opt for an ancestry DNA test featuring a cheek swab:
- It is convenient and simple. Using a swab is so easy that anybody can collect DNA.
- It is easy to transport. Swab samples are very easy to be locked in sealed pouches and transported. Swabs often come in dry transport systems.
- It is a painless sample collection. A buccal swab is painless. It just feels like a soft brush on the side of your cheek.
- It is widely available. The newest technology is adept at detecting DNA using these swabs. There is hardly any work required and that makes the whole process extremely fast, even for the lab staff.
- Swabs are as accurate as blood. Epithelial cells contain exactly the same DNA as blood cells. In other words, these swab tests are more than 99.9% accurate, which is the same in case of blood samples as well.
Can You Trust the Test Results?
Customers report receiving marginally varying results from different ancestry DNA kits. That can happen for a number of reasons. Chief among them is that there is no such thing as a complete database of human DNA samples, or even a sufficiently globally-representative one.
According to a report in Scientific American, when a technician searches a database of existing samples with known lineage for matches with your DNA, the quality of that match depends on the size of the comparative samples. Each company has its own database, so you may get different results from different companies.
Age and ethnicity also factor into the accuracy equation. If you’re not of white European descent over the age of 30, you will not get the most thorough match possible. The size of the database of possible DNA matches—known as reference populations—is not all that matters. Variety plays a role, too.
So far, the matches produced for non-white customers, and anyone with lineage traced outside of Europe, are typically far less accurate because they draw from a much smaller subset of DNA samples available for comparison.
We don’t really know how accurate these tests are in determining ethnicity and genealogy, genetics expert Sheldon Krimsky told Tufts Now.
Krimsky cites three barriers to test accuracy:
- Companies don’t share data with each other
- Collection and analysis methods are not validated by an independent group of scientists
- There are no agreed-upon standards of accuracy
While the ancestry DNA industry may as yet lack comprehensive regulation, consumers can find confidence in one fact. Companies using Puritan swabs have an edge in the purity of the samples collected and analyzed.
Earlier this year, the International Standards Organization (ISO) certified that products manufactured by Puritan conform to the global ISO 18385:2016 standard. That means Puritan’s forensics products are manufactured in an environment where stringent controls are in place to "minimize the risk of human DNA contamination in products used to collect, store and analyze biological material for forensic purposes."
So you might be wise to read ancestry DNA results with some skepticism. But you can certainly believe that companies using Puritan swabs are helping their cause for accuracy by using the best products on the market.
Would you like to learn more about Puritan DNA collection products? Contact us today.