AncestryDNA SideView | Ethnicity Inheritance | What is Phasing?

Diahan Southard

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AncestryDNA Sideview™ now estimates your parents’ ethnicity regions–without them even taking a test! They can do this because of the massive size of their database and the use of phasing. What is phasing? Here’s a quick, easy explanation of this exciting technology.

Every day is an exciting day in the DNA world. But TODAY is a cut above the usual excitement.

Ancestry has released a new technology called Sideview that empowers discoveries about each of your parents’ sides of the family–even if your parents themselves have not taken DNA tests! This is the first time any company has been able to do this, just by looking at your DNA and your matches. The tool released today estimates your parents’ ethnicities–and more is coming.

We will get into the nitty gritty of this exciting feature below, but actually the bigger announcement is not this one feature. It is the SCIENCE that is fueling this feature: phasing.

What is phasing?

SideView™ is a technology that builds on and improves the technology of phasing. Remember, you have two copies of each chromosome. Phasing is the process of reconstructing those two chromosomes for each parent at each chromosome. In this article we explain that phasing is like taking two similar sentences and trying to figure out the order of the words in each sentence. 

Keep reading. You’ll see how phasing works–colorfully–in the explanation below.

Ancestry’s SideView™ Technology

Actually, Ancestry has been phasing your data for years. However, previous phasing technology relied on DNA databases that could report which sections of DNA most people had most of the time, but it wasn’t personal to you. Or, to build on our sentence analogy, previous phasing technology has a list of most-often-seen phrases that they then use to reconstruct your most likely sentence structure for each parent.

But this new SideView™ technology is different. Instead of using a database of best-guesses, they are reconstructing your two parents’ chromosomes based on the DNA you share with your DNA Matches. This works because you are only sharing DNA with any given match on just one of your chromosome pairs, not both. (The two exceptions to that rule are in cases of endogamy, or for your sibling or their descendants). This is only possible because of Ancestry’s large database of over 20 million people tested.

Here’s how it works:

Let’s say these are the two chromosome 9’s you received from your parents (one from mom, one from dad):

Ancestry tests your DNA, and it comes out in a mixed up jumbled up mess, like this:

With the SideView technology, Ancestry identifies individuals in the database who share DNA with you and with each other, and they become pieces of your chromosome puzzle. The locations where your puzzle pieces connect are actually overlapping DNA segments, which ensure they are assembling your chromosome correctly:

The result is a reconstruction of your two copies of chromosome 9. One you received from your mom, and one from your dad.

Ancestry is just starting to tap into the power of this technology with their first feature. You can now see which ethnicity results came from your mom, and which you received from your dad.

So does it work? Ancestry’s science team reports that for 90% of its customers, it will work greater than 95% of the time. That’s pretty amazing. And those other 10%? Well, you know who you are (maybe). You are those who have significant endogamy (the practice of marrying within the same culture or location for several generations) in your family tree.

Exploring Your Parental Ethnicity Inheritance

To access this feature, you first need to take an AncestryDNA test, if you haven’t already.

Then log in to your results. Go to your DNA Story, and scroll down past your initial ethnicity percentages (which were also updated based on this feature!!) until you see “Ethnicity Inheritance.” Then click on “View Breakdown.”

On this page you will see the same results with two views. First, you will see a side-by-side view of your ethnicity results with the new parent split on the left, and the full you on the right. Remember that Parent 1 could be your mom or your dad.

Underneath this view you will find a detailed view. This is just the same information broken down by percentage.

What next?

What should you do with this information? Start by taking a look at your breakdowns to see if you can identify which of your parents is Parent 1 and which is Parent 2. I’m guessing it won’t be long before Ancestry adds the ability for you to assign that.

If possible, identify which specific ancestor on your mom’s side or dad’s side may have contributed that amount of shared DNA. Then look for any ethnicities that are not already represented in your family tree, and note which parent’s line contains that ancestor(s) contributing those percentages.

Ancestry’s press release makes this promise: “This is just the first feature as a result of our brand new proprietary SideView™ technology….In the coming months, Ancestry will use SideView™ technology to show customers DNA matches by parental side, community and journey patterns for each parental side and even more about your inherited DNA.” In other words, more is coming!

More will ALWAYS be coming in DNA discoveries. That’s why we created the AncestryDNA Tour with Your DNA Guide. This on-demand experience helps you understand EVERYTHING you can get from your DNA test results–including SideView at Ancestry! Your Tour includes a series of short video tutorials (about 90 minutes in total) and companion activities that help you apply what you learn to your own results. You can revisit your Tour anytime you like, and your companion workbook and quick reference guide become a useful reference for you as you continue to explore your AncestryDNA results in the future.

Limited-time BONUS: Purchase the AncestryDNA Tour by Thursday, April 14, 2022, and you’ll receive an exclusive invitation to my virtual Ancestry Afterparty, where we’ll celebrate and talk about what you learned and what next steps you can take!

Take the AncestryDNA Tour!


<a href="" target="_self">Diahan Southard</a>

Diahan Southard

As founder and CEO of Your DNA Guide, Diahan Southard has been teaching people how to find family history answers in their DNA for several years, and she's been in the genetic genealogy field since its infancy. Diahan teaches internationally, writes for popular magazines, consults with leading testing companies, is author of Your DNA Guide–The Book, and producer of Your DNA Guide–the Academy, an online learning experience.

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  1. . You are a gift

    I will need to re-read this a second time but it sure sounds exciting. In three or four reads it might even make sense to me not that it’s all that far off now. What a weird and wonderful ability you have to see and put things Colorfly and graphically so we can understand. You are a gift

  2. Greta V. Irby

    Oh Diahan, this is so nice what Ancestry has created here. I will have to check my info to see what I have. I am wondering if this is what my cousin was telling me yesterday which included her parents. I am very sure I will like this a lot and I am looking forward to.learning all about it. I was thrilled with ThruLines, I hope the same for this.
    I signed up for the DNA TOUR after midnight last night. Can’t wait for my materials to come. Here’s luck for all of our learning everyhing!!

    • Diahan Southard

      Greta! Thanks for commenting. You have access to the AncetryDNA Tour right now! Nothing will be coming in the mail. Just login and get started!

  3. Jason Lee

    Phasing is a reasonably straightforward concept. But I haven’t found information clarifying how Ancestry decides to sort the chromosomes into the two groups.

    • Diahan Southard

      They are using your DNA matches and the overlapping DNA they share with each other to reconstruct your chromosomes.

  4. Patti

    This technology has confirmed a suspicion I have had for some time. This has identified the part of my DNA in question and will help me identify even further my grandfather’s matches. It is so cool.

  5. Shirley Jenkins

    Thank you so very much for this tutorial. I am sure that I will have to keep re-reading to be able to really digest it all. So I am very thankful that I can go back again and again.
    I am looking forward to the reading the book.

  6. Elizabeth Smith

    Is “side lines” at all connected to the genealogy in one’s tree as is “thru lines?” Likewise, are the ethnicity estimates on Ancestry connected to one’s tree?

    Many thanks,

    • Elizabeth Smith

      Excuse me, I meant Side view.

  7. LaJoy

    This was very helpful but as an African American whose ancestors were enslaved, my African and my European ancestors may be as far back as the 1700s and I don’t know who they are. I can go back to 5 or 6 generations depending on the line but none were born in Africa or Europe. Is it possible to use close matches to help me determine which parent is 1 or 2? Am I overlooking something that will aid in this identification?

    Thanks so much. I really enjoyed the AncestryDNA course and I purchased your book when it was published. It has been helpful but I clearly need to reread it.

    • Diahan Southard

      Yes, you can look at the shared ethnicities of your close cousins to try to help you sort things out. But even then, it will be difficult if your parents had similar ancestry. I know Ancestry is planning on releasing additional tools based on this technology, so likely those additional tools will help you as well.

  8. Karen Langford

    This is a great tool. I have one problem. I know who my mother’s family is, but I don’t know my biological father side except who I share DNA matches with. I have had my half-brother do a DNA test. But, it still has been hard to know for sure which side is P1 or P2. My mother was born a Gallagher, so I would assume that she would share the Irish DNA. I hoping I will be able to learn more how from this class.

    • Danielle Francis

      Hi Karen, I’m so glad you’re joining us for the AncestryDNA Tour! Definitely take a look at that video in the Tour, it covers this process you’re describing.

  9. Steven Lobdell

    Thanks, I was not aware of this new feature of AncestryDNA

  10. Carley, Carol

    Loved the Tour, learned new things that were there before the Side view! Was wondering on Thru Lines if you have matches on common ancestors that you think are your common ancestors but don’t have a genealogy paper connection if you are on the right line of connection for that Common Ancestor?

    • Danielle Francis

      Hi Carol, So glad you’re enjoying the Tour. When using Thrulines, we always recommend to use other sources to verify what you’ve found. Take a look at our YouTube video on Thrulines for more information why:

    • Diahan Southard

      That’s tricky. I call ThruLines a “cheating” tool. That means that it is essentially copying information from other places, so you need to evaluate it yourself to see if it is correct. So think of it like a hint, not proof.

  11. Liz Scheidt

    I was sure when I saw my results on Ancestry that Ancestry could not possibly know which parent gave me my ethnicity. I have to admit, they nailed it. Even though Ancestry does not know which of my parents is parent 1 or parent 2, they got the ethnicity correct. Your explanation of how it works has been a great help in my understanding of how they were able to do that. Thank you.


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