DNA Testing 101

Living DNA Test boxSo you’ve heard all about the craze about at-home DNA tests, you’re interested in digging deeper into your family heritage but are confused on where to start. Don’t worry we’re here to help! We understand that navigating the DNA test world can be a bit overwhelming. There’s so much scientific terminology, so many types of tests (with varying results) not to mention so many unknowns as far as what to expect with your at-home test. Here at Exploring Life’s Mysteries we’ve been researching everything there is to know when it comes to DNA tests (since 2014!).

Over the years, we’ve received hundreds of comments from our readers with specific questions regarding all things DNA testing. So we compiled the essentials in one easy to reference place. We’ll define the different kinds of DNA tests, how testing works, and what you can do with the results. Ready to get started? Read on to learn more or use the menu below to jump to the section you are looking for.

DNA Testing: Getting Started

Why the recent popularity of DNA tests? Scientists have made a lot of progress in sequencing the human genome through the Human Genome Project and other research over the last decade. What they’ve discovered makes DNA testing more accurate than ever before — and more discoveries are made every day! But what can you discover with these tests exactly? We’ll get into that in the next section, but first we wanted to dive deeper into the terminology since there’s a lot of jargon when it comes to DNA tests.

  • What are genetic markers? genetic marker is a DNA sequence with a known location on a chromosome. Scientists use genetic markers to identify cells, individuals, populations, etc.
  • What does autosomal mean? Autosomal refers to a chromosome that is not a sex chromosome. People have 22 pairs of autosomes in each cell, as well as 2 sex chromosomes (X & Y in a male and X & X in a female).
  • What is shared DNA? Two people who share identical segments of DNA share a recent common ancestor. The relationship between relatives (siblings, cousins, etc.) depends on the length and number of these identical segments.
  • What is deep ancestry? Deep ancestry is based on either mitochondrial DNA (maternal, or coming from your mother’s side) or Y-chromosome DNA (paternal, or coming from your father’s side), and it shows a single line of descent. It’s often referred to as a direct maternal line or direct paternal line, going back hundreds to thousands of years. 
  • What does haplogroup mean? haplogroup is a genetic population (group of people) who share a common ancestor on the direct paternal or maternal line. 
  • What is Y-haplogroup, E3a, Q3, etc.? Each haplogroup is assigned its own group “name,” which consists of a letter of the alphabet followed by more specific refinements indicated by additional number and letter combinations.

Now that you have a better understanding of the overview, let’s define the various types of tests, what to look for and who can take them.

Recent Ancestry: Autosomal DNA Test

An autosomal DNA test for ethnic origin matches your DNA with population samples and studies from across the globe. When you get your DNA test results back, you’ll get a report that gives you a mixture of percentages. These are your unique percentages of where your ancestors lived in defined geographical regions, i.e. 82% British Isles, 10% Eastern European, 2% Native American and so on.

Autosomal DNA tests trace back anywhere from five to ten generations on both your mother and father’s sides of the family. Each company’s ethnicity report differs slightly by their defined global regions, how they present their data to you, and the number of population studies they use in their analysis. Your percentages can also differ slightly because of each lab’s unique testing methods. Some autosomal tests also look at parts of your DNA going back even further.

Autosomal Testing

  • Who Can Take The Test: Males and females.
  • What it Tests For: Autosomal DNA testing matches with other individuals based on a certain amount of shared DNA.
  • What it Can Reveal: Testing can’t predict exact relationships, but you can expect to find matches as far out as 5th cousins and in some cases even further. Tests analyze shared DNA and give you your matches as well as how much DNA you have in common. Autosomal tests also identify your ethnic origins from around the world.
  • How Far Back Are Results: Autosomal DNA tests trace back anywhere from five to ten generations on both your mother and father’s sides of the family.

Example: An autosomal DNA test for ethnic origin matches your DNA with population samples and studies from across the globe. When you get your DNA test results back, you’ll get a report that gives you a mixture of percentages. These are your unique percentages of where your ancestors lived in defined geographical regions, i.e. 82% British Isles, 10% Eastern European, 2% Native American and so on.

NOTE: Each company’s ethnicity report differs slightly by their defined global regions, how they present their data to you, and the number of population studies they use in their analysis. Your percentages can also differ slightly because of each lab’s unique testing methods.

Ancient Ancestry & Haplogroups: Y-DNA and Mitochondrial DNA Tests

Autosomal DNA tests look at chromosomes 1-22 that you’ve inherited from both your parents. The Y-DNA and mitochondrial DNA (mtDNA) tests can tell you where your ancestors from your direct paternal line and maternal line lived thousands of years ago. For the stone age aficionados among you, some tests can even tell you how much Neanderthal DNA you have!

Mitochondrial DNA Testing

Both males and females can take an mtDNA test, which reveals your direct maternal line ancestry. MtDNA is passed down from mother to child each generation. All humans trace back to Mitochondrial Eve, who lived in Africa an estimated 200,000 years ago. Over time, her descendants broke out into different branches called haplogroups, and an mtDNA test can predict your mtDNA haplogroup.

Y Chromosome DNA Testing

Only males carry the Y-chromosome, so women won’t benefit from taking this test. A Y-DNA test traces direct male-line ancestry — son to father to grandfather and so on. Women can learn something from this test by having a brother, father, paternal grandfather, paternal uncle or a male cousin (your father’s brother’s son) take a test for you. This test can tell you which Y-haplogroup you belong to if you’re male. Your Y-DNA haplogroup reflects the ancient ancestry of your paternal line. Some haplogroups indicate clear ethnic groups. For example, the Y-haplogroup E3a is the most common among African Americans, and Y-haplogroup Q3 solely includes Native American populations.

Mitochondiral Testing (mtDNA)

  • Who Can Take The Test: Males and females.
  • What it Tests For: mtDNA tests along the direct maternal line, examining genetic markers on your mtDNA, which is passed down from mother to child each generation.
  • What it Can Reveal: Your direct maternal deep ancestry and which haplogroup you belong to.
  • How Far Back Are Results: All humans descended from Mitochondrial Eve, who lived an estimated 200,000 years ago in Africa. Her descendants are organized into different branches called haplogroups. mtDNA test results predict your mtDNA haplogroup.

Y Chromosome Testing (Y-DNA)  Y111

  • Who Can Take The Test: Males only (because women don’t have a Y-chromosome). While females can’t be Y-DNA tested, they can have a brother, father, paternal grandfather, paternal uncle or paternal uncle’s son (their cousin) take a test for them.
  • What it Tests For: The Y-DNA test traces direct male-line ancestry — the majority of the Y-chromosome is transmitted from father to son with very little change. Each male’s Y-DNA test results are compared to other males’ results to find out their most recent common ancestor (MRCA) in their direct patrilineal lines.
  • What it Can Reveal: This test can tell you which Y-haplogroup you belong to if you’re male. Your Y-DNA haplogroup reflects the ancient ancestry of your paternal line. Some haplogroups indicate clear ethnic groups. For example, the Y-haplogroup E3a is the most common among African Americans, and Y-haplogroup Q3 solely includes Native American populations.
  • How Far Back Are Results: Like mtDNA tests, Y-DNA tests can go back hundreds of thousands of years.

Now that you have a better understanding of the terminology when ordering a kit, you might be curious as to what kit you should order and what it will reveal? We’ll get into that now.

Which DNA Test Is Best For What?

We often get asked which test is best for revealing what type of information. Every DNA testing company has its own unique strengths and thus the results are better for certain types of data. Based on our ongoing research, we’ve chosen what we feel is the best DNA test for each of the following criteria:

DNA Test FAQ’s

Here are some additional questions we get asked from time to time.

Do my parents need to take a DNA test too for my results to be accurate? It depends on what type of information you’re looking for. It’s not necessary if you just want general ethnicity results. An autosomal DNA test will tell you what’s been passed down through your mother and/or father’s blood line, so save yourself the money! But keep in mind, each person inherits different percentages of each parent’s DNA, and every person is different. So if you want the most complete results, everyone in the family should test.

Do tests tell you what countries your ancestors lived in? In most cases no. Most ethnicity breakdowns involve broader regions, rather than specific countries.

Who offers the best bang for the buck? Family Tree DNA has the lowest autosomal test price tag.

Can I transfer results from one company to another? You can’t upload other companies’ DNA test results to either Ancestry.com or 23andMe; however Family Tree DNA does allow you to upload results from AncestryDNA, 23andMe and Geno 2.0 to match your results to their DNA database. My Heritage also accepts other results, but their database isn’t as sophisticated or comprehensive. There are also a few free sites where you can upload your raw data results to help you match your DNA to others. The most popular is GEDmatch.com.

Do companies share my results with researchers or third parties? The best testing sites don’t share your DNA results with third parties, like insurance companies.

How Does DNA Testing Work?

How does DNA testing work? DNA testing isn’t easy to understand on a scientific level, but we’ll try to explain it in laymen’s terms to help you get the gist! More than 99 percent of your DNA is the same as everyone else’s in the world. But there are small groups of sections across each person’s genome that differ (these variations make you the unique person you are). DNA analysis looks at these small sections, called “markers,” to create your DNA profile —  a unique genetic fingerprint.

As we mentioned above, not all DNA tests are the same. A carrier status DNA test, for example, focuses on the specific markers known to be associated with certain inherited conditions. On the other hand, DNA genealogy tests focus on specific markers related to our ancestry. If you’re considering purchasing a home DNA test, it’s important to choose the kit that reveals the kind of information you want. Read this for a step by step look at the DNA testing process.

What Will You Discover?

This news story from CBS New York shows some shocking success stories about what people have recently been able to discover (or hope to uncover) thanks to at home DNA tests.

Still Have Questions?

Congrats if you made it to the end. We tried to answer all your questions but if there’s something we neglected to cover, feel free to ask us in our Reader Questions.