How Does An AncestryDNA Test Work?

DNA
30 September 2023
by Ancestry

An AncestryDNA test is simple. You order a kit, send in your saliva sample, and voila. You get an email weeks later telling you when your results are ready.

Those results reveal your ethnicity estimate, people you may be related to, and new details about your unique family history.

But how does an AncestryDNA test actually work? It’s as simple as 1-2-3.

1. Getting your raw DNA data

After the robots and trained technicians in the lab are done getting your DNA from your saliva, that’s when things get really interesting.

Your DNA is measured at about 700,000 locations to generate raw DNA data, which looks like this:

Segment of raw DNA data.
Here’s an example of what raw DNA data looks like.

Our science team uses the raw DNA data to determine your ethnicity estimate as well as identify people you might be related to.

2. Discovering your DNA origins

We compare your data to the population data from 2,600+regions around the world to estimate what populations you are genetically similar to, based on current research. After running the comparisons, we give you an ethnicity estimate.

Your data is compared to population data from over 2,600+ regions.
Your data is compared to population data from over 2,600+ regions.

We run this comparison 1,000 times to get the best estimate of what regions you are genetically similar to, based on current research. After running the comparisons, we give you an ethnicity estimate.

Here’s an example of what a set of ethnicity results could look like:

What’s fascinating is your ethnicity results are unique to you. If you had additional family members tested, their results might look different. Your sister, for example, could be twice as Irish as you.

3. Finding your DNA matches

In addition to an ethnicity estimate, we compare your DNA to everyone else’s in our database. Currently that database consists of over 23 million individuals.

Depending on how much DNA you share with any given person in the database, we estimate a possible relationship. This is how DNA can help you find cousins you never knew you had.

Screen Shot 2016-11-30 at 3.46.14 PM
We compare your DNA to almost 10 million samples in our database.

And as our database grows, we will continue to compare your genetic data to anyone else who takes the AncestryDNA test. So you’ll have continuous possibilities of finding new connections.

Now that you know how it works, are you ready to discover your DNA story?