Do you want to know more about your ancestors and family tree?
What's your name? What country are you from? The ability to get simple, quick and affordable answers to these questions is at the heart of what it means to be human, and the genetic testing market is now worth nearly $1 billion per year.
The best DNA test kits provide you with detailed, personalized reports on... what? Where did your forefathers and mothers come from? No, not at all. They can help you research your genetic ancestry and ethnicity by telling you where your DNA came from today, but they aren't the quick fix you might think. Here's how DNA tests work, what the benefits and drawbacks are, and how to pick the right one for you.
Differences Between DNA, Genes, and chromosomes?
DNA is made up of two long molecules that carry genetic instructions for cells to function and reproduce. All living things contain DNA. It's made up of two strands that wind around each other in a double helix. Genes are sections of those strands that determine specific characteristics. Every cell's nucleus contains chromosomes, which are made up of DNA. Each cell contains 46 chromosomes, 23 from each parent.
However, the manner in which DNA is inherited is unpredictable. Even twin brothers in the same family can inherit different segments of DNA from their parents. Cousins share some DNA, and you can see your genetic matches if you sign up for a cousin-matching service from a DNA testing company. When it comes to third cousins, DNA isn't much help. You may have no DNA in common with some of your ancestors if you go back several generations.
What you can learn from DNA test kits
DNA test kits collect saliva or cheek swabs, which you then send to a lab, where your DNA is extracted. Basically, you spit into a tube or use a cotton swab to swab each cheek twice. What you get back – either in the mail or, more likely, online – appears to be informed about your ancestors' origins. In a nutshell, your ethnicity is a breakdown of your genetic ancestry.
However, DNA test kits do not reveal the origins of your ancestors. Trying to place your genetic ancestors in a geographic location is inherently problematic because human history is the history of migration.
So, how exactly does the procedure work? Different bits of your DNA is loosely assigned to geographic locations by cross-referencing segments of your genome with others in a database. Companies frequently use reference samples from people in the area who have four grandparents, and similar DNA samples from a given location are clustered. This aids in determining a likely connection to a location over long periods of time, but many assumptions are made. It's possible that your outcomes aren't unique.
Regardless, you'll receive information and images about the general populations and regions to which your DNA is linked. For example, you might learn that you're 81 percent European and 9 percent Asian, but that data might also reveal that you're 41 percent English and 40 percent, Welsh. These figures are based on the size of the company's databases, as well as the algorithms and statistical techniques employed.
You might also be told that you're related to other people who have taken a DNA test with that company, with cousin-matching being the most common service.
Why do you need more than one DNA test kit?
AncestryDNA, LivingDNA, Family Tree, MyHeritage, and 23andMe are among the industry's top genetic companies. After you've completed one test and received your results, you can upload your raw DNA data to another testing company to use their databases and algorithms.
This is due to the fact that the outcomes will differ. With data from new locations added over time, the databases of various companies grow larger and thus better, while the reference populations used for specific regions grow larger and more reliable. Algorithms, software, and artificial intelligence are all improving. This is why today's DNA test kit results are far more detailed than when they first became available a decade ago – and will continue to improve in the future.
It's also worth noting that, until recently, DNA testing companies primarily served people of European ancestry, owing to their popularity in North America and Europe.
The three kinds of DNA tests
There are three types of genetic genealogy tests, each of which reveals different information about your ancestors:
Autosomal (atDNA): This is by far the most popular and useful DNA test for ancestry, and it's also known as "family finder" or "your ancestry." It can trace a person's ancestors back up to seven generations, which is useful for cousin matching. As a result, it is the standard offering for all DNA testing companies.
Chromosome (yDNA): The Y-chromosome, which is only found in men and passed down the paternal line, is used in this test. A man's ‘yDNA’ mutations can connect him to a genetic population with whom he shares a common ancestor.
Mitochondrial (mtDNA): This one traces your maternal forefathers and mothers. It is available to anyone. Your mtDNA mutations can connect you to a genetic population with whom you share a common ancestor.
Choosing the best DNA testing kit for you
As an entry-level product within a larger offering designed to help you investigate your individual family history, many DNA testing kits offer genetic readouts on your ancestry. It also compares your DNA to that of new customers, allowing it to provide you with new information years after your initial cheek swab.
Here are the key differences between the most popular services – all of which include autosomal testing by default – but for more information, see our article on the best DNA test kits:
AncestryDNA: Uses a saliva test and has a 20 million-strong database – the most of any – as well as access to 30 billion genealogy records for family tree research.
Living DNA: uses a cheek swab and has a million-person database. It claims to have data from all over Africa, implying that African Americans and European Africans will see better results. It also has a strong focus on British ancestry.
Family Tree DNA: It uses a cheek swab and has a 1.4 million-person database, so it's not ideal for cousin matching. You can also have your DNA cross-referenced with the company's yDNA and mtDNA databases for an additional fee.
MyHeritage DNA: It works with a cheek swab and has a 4.5 million-strong database. It also gives you access to 12 billion historical records and integrates your genealogy research.
23andMe: It costs $99, uses a saliva test, and has a 12-million-strong database, making it the second-largest. As a result, 23andMe is useful for cousin matching, and it also provides health information.
Do DNA test kits worth it?
DNA test kits aren't a scam, but you should be aware of their limitations and realize that they're merely a byproduct of much larger goals. Researchers, for example, are using anonymized DNA test results to create maps of human migration patterns, as well as to develop personalized and population-based healthcare, in part by identifying people at risk of genetic diseases. The expansion of DNA test kits is excellent news for population genetic modeling.
However, DNA test kits do not provide simple, quick, or 100 percent reliable information about a person's ancestors. So, if you're researching your ancestors, get a DNA test kit and incorporate the results into your research. However, if all you want is a quick DNA-based sense of identity – confirmation of your own unique heritage and ancestral roots – DNA test kits won't be accurate enough.