5 Things You Need to Know about AncestryDNA


Welcome back to Tenacious Genealogy! Today, I’m going to focus on the genetic aspect of genealogy. Genetic ancestry adds a new dimension to family history, sometimes enriching our sense of identity and sometimes making us re-evaluate it. But it is an aspect that can’t really be ignored. Because of this, there are a variety of companies (both genealogical and not) that offer DNA tests to consumers. I’m going to talk about Ancestry’s offering – AncestryDNA.

1) AncestryDNA is massive

AncestryDNA, just like the website that it is a part of, is the big fish in the pond of DNA services. It’s been around for several years and according to its website, has over 5 million DNA samples (as of August 2017). EDIT: as of September 2018, they had over 10 million samples.

To put this into context, the next biggest company in the realm of genetic genealogy is 23andMe. 23andMe just surpassed 2 million samples in April of 2017. (Over 5 million in September of 2018) The three other main competitors (Living DNA, FTDNA and MyHeritage) have just started their services, so their databases are still relatively small. (According to DNAGeek, these are the rough estimates for September 2018.)

In regards to genetic genealogy, database size is a decent predictor of how accurate the results will be. Basically, the bigger the database, the more people your sample is tested against and thus, more accurate results. So, in this regard, AncestryDNA’s results are (currently) the most accurate. However…

2) AncestryDNA results are nuanced

So genetics (and genealogy) are usually more nuanced than they seem at first glance. The first thing to know is that DNA is usually measured in a unit called a ‘centimorgan‘. I won’t get into the nitty-gritty of what a centimorgan is, but for the sake of genetic genealogy, it’s the measurement of the distance between genetic markers in autosomal DNA (the DNA that everyone gets from their parents).

Centimorgans is a big part of how services like AncestryDNA can tell how closely related someone is to another person. Generally speaking, the more centimorgans you have in common with someone, the closer you are related to them. A great  basic visual chart is located here.

However, if you have multiple common ancestors with a person, you might have more centimorgans in common than the average person with that same relation. For example, if both a person’s grandfather and grandmother had ‘Smith’ ancestry (even if they weren’t direct cousins), their descendants may have more centimorgans in common than normal. You generally see this within groups that practice a lot of endogamy, but that’s a whole other blog post to write about.

Similarly, you only get up to a certain percent of a parent’s DNA. Usually it’s about 50% (I share 50% of my mother’s DNA and 49.9% of my father’s according to AncestryDNA), so with each generation, the chance that certain pieces of DNA got passed down to you goes down due to something called ‘recombination‘ (This is a really good blog post on the subject).

For example: my great-grandmother was full-blooded Swedish/Scandinavian. Which means I should be about 12.5% Scandinavian (given that I’m not getting that ancestry from any other lines). But according to AncestryDNA, I’m 6%. And that’s okay. All it means is that either my grandmother or father were more like their fathers, genetically. Or both. Or even that I’m more like my mother than my father (which technically is true).

Also… because of recombination, even if you and your siblings all get 50% of Mom and 50% of Dad, that doesn’t mean you all will get the SAME 50% from each parent. It’s not uncommon for siblings (even fraternal twins, triplets, or other multiples) to have a range of ancestry percentages. Ancestry has a good informational page about this concept as well.

Lastly, results from AncestryDNA are always changing. But this is a good thing. They are changing because the database that Ancestry is using is getting larger (and more diverse).  As databases such as AncestryDNA’s get larger, there are more DNA samples to match against yours.

An example of this that I’ve experienced is the percentage of Irish (technically Celtic/Gaelic) DNA that AncestryDNA says I have has shot up since I initially took the test. Because I only have one known Scottish (which is Ancestry includes in Irish DNA) line, I expected maybe 10-12% Irish DNA. And originally there was less than that  – about 7-8%. Now my results show me as have 19% ‘Irish’ DNA. (Which probably explains my fair complexion and inability to tan…)

Based on the growth of AncestryDNA, I can only assume that more people with ‘Irish’ DNA (really Celtic/Gaelic) have taken the test since I did and so AncestryDNA can more solidly tell me that I am a good part Irish/Welsh/Scottish.

3) AncestryDNA can (maybe) tell you whether you have Native American/First Nations ancestry, but not which tribe

Some people take the AncestryDNA test in order to find out whether that story of having a Cherokee princess as a great-grandmother is true. However, AncestryDNA isn’t going to tell you if you are part Cherokee (or Ute, Iroquois, Apache, Sioux, etc, for that matter.)

While AncestryDNA can tell you whether you have Native American/First Nations ancestry (within reason – check out this article that goes more in-depth into the subject of Native American ancestry and genetics), it is virtually impossible for AncestryDNA to differentiate one tribe from another solely on genetics.

This is primarily because most of the different tribes (at least in North America) are part of the same haplogroup, so the majority of their genetic markers are going to be similar to each other. As well, anecdotally, there have been less Native American/First Nations people who have taken DNA tests (especially the AncestryDNA test), so that subgroup is less represented in the overall database.

 4) AncestryDNA can connect you with distant family members

AncestryDNA, as it has evolved, has created a few pretty cool areas to explore your genetic ancestry.


Genetic Communities – These are groups of people who are connected to each other through DNA because of having common ancestors in a specific region. This is a relatively new aspect of AncestryDNA (still in beta, technically) and seems to heavily rely on how many people/descendants from a particular area have taken the AncestryDNA test. According to Ancestry, they have about 300 genetic communities around the world and will be introducing more in future months.

Currently, I have four genetic communities right now – two from French settlers in Quebec and the surrounding areas, one from Sweden, and one from Mormon pioneers in the intermountain west. However, family members that I’ve talked to (and who have ancestry in Asia) have noted that genetic communities haven’t popped up for them yet. This could possibly be because there aren’t enough samples yet from the part of Asia that they are from.

DNA Matches – The main ‘connector’ area in AncestryDNA. It’s here that you can see other people who share sections of DNA with you. Ancestry DNA even organizes them from closest relation to distant relation.

The big thing to understand about DNA Matches is that however close you are to another person is an estimation. The estimation is more accurate for closer relations and then gets more fluid the farther removed you are from a person. For example, you and your parent (or child) have 1 degree of separation. You and a sibling have 2 degrees of separation. You and a cousin have 4 degrees of separation. With all of these, Ancestry will tell you that there is a very high chance that the two of you are closely related.

The most direct way of having 4 degrees of separation – being 1st cousins.


Another way to have 4 degrees of separation. (In this case, the two individuals are great aunt/uncle and great nephew or niece, but Ancestry would organize them in the 1st cousin slot because there are 4 degrees of separation.)


But… by the time you get to predicted 4th cousins, you have 10 or more degrees of separation.
10 degrees of separation!


Which is why this is about as far out as AncestryDNA will organize your relations. After that, you have Distant Cousins, which AncestryDNA notes as being distant enough that while you share DNA with them, it isn’t enough to be totally certain.

DNA Circles – These are groups of people that Ancestry can tell are related to you through a common relative. On its website, Ancestry states ‘A DNA Circle is a group of individuals who all have the same ancestor in their family trees and where each member shares DNA with at least one other individual in the circle.‘ While it is an aspect of AncestryDNA that is still in beta, it is an interesting item to play around with. If you click on the question mark in the upper right-hand corner of the ‘DNA Circles’ block, it will pull up a bunch of questions and answers about DNA Circles.

5) AncestryDNA can uncover family secrets

And now the uncomfortable side of AncestryDNA…

For all of the cool and wonderful information you can find out with it, there is always the surprises and stories that are hinted at by DNA.

Sometimes these surprises are benign (like my mother finding out she has DNA that was common to people in Great Britain – ‘But I don’t have any English ancestors!‘) Other times, it isn’t so benign (like when a family finds out they have a sibling or half-sibling they never knew about). And then there are the times when people think they have a certain heritage and come to find out that they don’t, leaving them to try and re-evaluate who they are.

These stories have become more frequent as time goes on and more people do DNA tests. A couple recent articles on this happening are here and here.

Unfortunately, as many people who’ve taken DNA tests such as AncestryDNA have found out, science doesn’t give a **** about feelings or who we ‘identify’ as. Or family secrets. Or social mores. More often than not, we share DNA with groups that we may not necessarily like or be fond of. People may find out that the culture or ethnicity that they thought they were, really isn’t part of their genetics. This is a risk taken by anyone who takes part in DNA testing. While DNA is nuanced (and may not tell the full story of our ancestry), the facts it gives do not lie.

That said, taking a DNA test (especially through AncestryDNA) isn’t a bad thing. I am glad that I took mine, and it certainly made me want to explore my ancestry and heritage a lot more. Given the large (and ever-growing) database that backs up AncestryDNA results, I would highly recommend it. Right now, pretty much all of the DNA services are offering sales for the holidays, so if you are interested in purchasing an AncestryDNA kit, now is the time to do it. You can do this through their website.

Questions? Comments?

Questions or comments about AncestryDNA? Feel free to leave them below in the comment section! And if you like what you’ve been seeing here on Tenacious Genealogy – please subscribe to our email list. Not only will you stay up to date with the latest blog posts, but you’ll also get access to freebies such as ’10 Tips for Starting Your Genealogy’ and other fun ‘subscriber only’ items!

18 thoughts on “5 Things You Need to Know about AncestryDNA

  1. Debbra says:

    Love this! Easy read. Appreciate your time doing this post. I have been highly considering a DNA test and had many questions about which one to use. You gave me good insights to consider.

  2. Betty Clark says:

    I have three of my family lines done with names, dates etc. back to their countries of birth for many generations. They are all from France and Germany. Yet my DNA came back 56% Irish, English, Scot and Scandinavian. There is no one on the three lines from these countries. The only line I can’t trace is my Maternal Grandmother, but I can’t see how that much could be from her even
    if she was of the N. European mix.

    • Laura Nelson says:

      Your ancestry sounds a lot like my mother’s. She can trace her lines back to France and Germany at least 7-8 generations, which is why she was so baffled to find British DNA. Without looking specifically at your DNA results and family tree, the only thing that I can say is that there has always been a lot of migration between the continent (France/Germany) and the British Isles and that may be part of the reason that your DNA doesn’t match up completely with your family tree. A lot of people, depending on their fortunes, politics, or religious beliefs would move to an area or country where they would fit in more. The same could be said for people in Scandinavian countries migrating to places like Germany. Either way, it is fascinating and hopefully you’ll be able to find out more information about your family, especially your maternal grandmother’s side!

  3. Fran says:

    I have sent for my AncestryDNA kit. Is there any way to upload the results to other DNA companies to determine more matches? I am seeking an adoptive mother or father for a friend. He has his a DNA result from another company. Should he take more tests to obtain more matches?

  4. Jennifer says:

    You stated that your ancestry percentages change because of databases being updated with ancestry.com I would like to know if they automatically update the information or if you have to take another DNA test

    • Laura Nelson says:

      In my experience, the information is automatically updated. I’ve only ever had to take 1 DNA test with AncestryDNA.

  5. Kathy Wallace says:

    I had my DNA done a couple years ago and has been fun to research. I recently had my fathers DNA done to see if any Native American in his DNA as did not show up in mine but I can’t get to it. Could use some help being able to see it. Our ancestry membership is under my husbands name but I used my email to have results sent to and my dad is 87 and doesn’t use a computer. Any help getting to it would be appreciated.

    • Laura Nelson says:

      There are a couple things that could be an issue here. If you created an Ancestry account for your father’s DNA results (which Ancestry requires now), you would need to be logged into that account to see his results. If your Ancestry account is the one you use for DNA kits, double check to see if you are a manager on your father’s DNA test. If you are, you should be able to see his results. Lastly, depending on when you sent in your dad’s sample, it may still be processing. A lot of people do these DNA kits as Christmas gifts and so kits sent in around December/January often take longer to be processed than kits sent in at other times.

  6. Mike in Baltimore says:

    I have seen on Family Tree DNA.com’s Y-DNA test that they give actual names of ancestor males who share the same DNA, and who appear on the family trees of participants from its database. The list of names can go back to the 1700s and I can visit the uploaded family trees of those who they share. Does Ancestry.com’s Autosomal DNA test also provide the names of matching past ancestors from their database and/or the contact information of members in their database? If not, what is the test (whether or not Ancestry.com has it) which allows one to see if I have the name of an ancestor (to see if I share him/her with others) from the mid-1800s? Thank you

    • Laura Nelson says:

      Hi! I’ve been doing a bit of research to answer your questions and as for the first on about Ancestry’s DNA test and matching past ancestors/contact info – it depends. For example, Ancestry gives me several ‘Shared Ancestor Matches’. The first one (linking me to my mother) is private. (I.E. My mother has a private tree) Ancestry gives me the option to message her account regardless. The second shared match is with my great-aunt and because her tree is public, I can see our shared ancestor and how we are related to each other. I could also message her on Ancestry if I wanted. In either case, I can’t email them unless they have put their email address onto their Ancestry account and make it publicly available.

      As for other sites, I’m not as familiar with their resources connected to DNA kits, however, I would assume any site with the ability to build a family tree would have the same or similar capability.

      That said, if you are on Facebook, I would highly recommend joining the ‘Genetic Genealogy Tips & Techniques’ group, where there are a ton of people highly versed in the ins and outs of genetic genealogy and the various DNA kits.

  7. Patrick Thompson says:

    It has taken a year to really get a good grip on how to use the info you receive from Autosomal DNA testing. Once I dug in and learned that the system will automatically choose the most common relationship, and that the prediction may not be exact, it removed some of my blinders or “one dimensional” thinking. The visual chart listed under #2 above Is crucial to your success. I created a Basic excel spreadsheet of my top DNA matches down through 3rd Cousin listing the # of cm’s shared, segments, and projected relationship. That reduced my list dramatically but because I have “known” relationships I am now able to quickly compare what a 1st or 2nd cousin I “know” is correct should look like in terms of “cm” or centimorgans giving me a constant variable to compare with. By using a chart similar to the one outlined in #2 and because I have one printed, I can then see the relationship possibilities at a glance. This has helped me greatly. “Especially” on 1/2 matches (i.e. half sibling, half 1st cousin, etc.) The DNA world is mind boggling and anything that helps simplify is GOLD!
    Great Article!

  8. Dennis Calkins says:

    Thank you for this interesting article. As I was reading this, an only partially related thought occurred to me.
    There is no question that our DNA indicates how much we have inherited from our various ancestors. It’s also understandable that some people may be angry or simply very embarrassed by what some of their ancestors have done. The other side of this picture, which will not show up in our DNA tests, is the effects of being raised in one’s family.
    It’s very understandable that someone is terribly upset that an ancestor was, for example, a Nazi storm trooper, a murderer of Native Americans or Blacks, or an otherwise offensive person. I would guess that being aware of such a terrible person in the family gene closet might incline one towards never getting a DNA test done. Just because such a person may really exist, it does not insure that there are not other ancestors in one’s tree who were very positive and uplifting people.
    Whatever our historical ancestors have done, my personal bias is that it’s of greatest importance how we live our lives. Are we providing proper examples for our families, and looking for ways to have a positive effect on others? If we diligently do so, the likelihood is greatest that our children and theirs will be the kind of people that others will love, look up to, and enjoy being around.

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