Ancestry Blog » AncestryDNA The official blog of Ancestry Fri, 22 May 2015 11:42:14 +0000 en-US hourly 1 How AncestryDNA added new life to my family history research. AncestryDNA – Coming Soon to Australia. Fri, 15 May 2015 23:27:03 +0000 Brian Gallagher Read more]]> 1ComingSoon

I am privileged to work for a company that genuinely makes a difference to the lives of many thousands of people around the world. I have seen first-hand the breakthroughs, connections and family reunions that have been made possible by the records and trees available on Ancestry. Obviously, like many of you, I have used Ancestry to research my own family tree. I am Irish and my family has not left our home place for as far back as I can research, given the limitations of Irish records. Many of my grandparents’ siblings did leave. They traveled, as many Irish emigrants did, across the globe to the United States, Australia, New Zealand, Canada and South Africa. As a consequence I am more familiar with being found, than I am with finding others. Year after year throughout my childhood and in recent years too, family after family would arrive in Ireland to see the house where their ancestors were born and from which they had to leave in order to find a future in a foreign land. Thanks to resources like Ancestry these families were able to trace their family history right to my doorstep.

Being unable to go further back than I have with records, I have been anticipating the launch of AncestryDNA to see if it can give me that sense of discovery that I had seen so many times on the faces of my relatives as they returned to the birthplace of their ancestors. I honestly wasn’t sure what to expect from my AncestryDNA results. My parents are both Irish, as are their parents and their parents before them. Would it tell me anything?

After carefully reading the instructions, providing my saliva sample and activating my kit on the Ancestry website; I waited. When I got the notification email to advise the results were back I was a little nervous. What would they say? Am I 99% Irish as I suspected? Will I have any cousin matches? I rushed to open my Ancestry account and see my results.

To say I was overwhelmed was an understatement! It was difficult to take it all in at first glance. Not only did I have a cousin match, I had many cousin matches! I had expected to see matches at 4th cousin or more distant but I had a possible 3rd cousin match! Wow! I have since contacted this person and she is my mother’s second cousin. When I told my mother of this discovery, she was astounded. She was aware of her cousin’s name, but the families had lost touch many years ago and my mother had never met any member of that family. That changed yesterday when they spoke on the phone for over an hour. AncestryDNA made this reunion possible. What was previously just a name on a family tree is now a relationship in the real world.

I also had matches on my father’s side of the tree too, at 4th 5th and 6th cousin. I have not had the chance to go through all my cousin matches yet, I have over 50, but so far on my father’s side we have managed to finally find the answer to an old question. My father and a neighbour had always believed that our families were related, but neither of them knew how. Thanks to AncestryDNA I was able view the family tree of one of my matches in the United States and we have finally found out where the link is! My father could not believe that a simple saliva sample could hold the answer to a question he had been unable to find for decades.

Cousin matches are only half of the results process. AncestryDNA also gives you your ethnicity estimate. I was expecting to find out that I am somewhere around 95% Irish based on what I already know from my family tree. I was in for a surprise. I discovered that I am 85% Irish, 7% British, 4% Eastern European and some trace results from Scandinavia, Northwest Russia and Asia making up the remainder. Not what you might describe as a typical Irishman!

While AncestryDNA has answered many questions and solved some mysteries it has also raised new questions for my family history research. Not since I started my family tree have I been this excited about all the discoveries that lie ahead. I would recommend AncestryDNA to everyone who wants to learn more about their family history, not because I work for Ancestry, but because it is truly a revolutionary product that can take your research to the next level.

If you would like to learn more about AncestryDNA, or to add your name to our invite list, click here.

Once you taken the AncestryDNA test, please feel free to share your success stories with us on Facebook and Twitter .



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Breaking Down the Science Behind Your Ethnicity Results Tue, 05 May 2015 21:16:48 +0000 Anna Swayne Read more]]> Are you Scandinavian? Native American? Or maybe you have some Middle Eastern in you. If you’ve gotten your AncestryDNA results you know your unique ethnicity estimate. But have you ever wondered how we determine those results — and why your results can look so different from another family member’s? In this 6-minute video one of our scientists, Ross Curtis, breaks down the science behind the AncestryDNA ethnicity results.

Have more questions? Leave them in the comments below.

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Where in the World are the Ancestors of DNA Circles? Sat, 25 Apr 2015 13:00:42 +0000 Julie Granka Read more]]> While we often celebrate the discovery of the structure of DNA on DNA Day, today we’ll celebrate those who we got that DNA from: our ancestors.  We can also celebrate all of the people with whom we share DNA from those ancestors: from our siblings to our distant cousins.

AncestryDNA DNA Circles™ recognize both our ancestors as well as all of the connections we’ve made with distant relatives through our shared ancestors.  That’s because a DNA Circle is a group of people who all share DNA with others in the group, and who all also share a particular ancestor in their family trees.

Who are those myriad ancestors connecting more than 30% of AncestryDNA customers?

  • The average birth date of all ancestors of DNA Circles is about 1800, and roughly half of all ancestors of DNA Circles were born between around 1780 and 1820.
  • In the map below, we can see that most DNA Circle ancestors were born in the eastern half of the United States – but also abroad in England, Ireland, and Western Europe.
Approximate birth locations of ancestors of DNA Circles in the AncestryDNA database.  The birth location of each ancestor of a DNA Circle is indicated as a green dot.

Approximate birth locations of ancestors of DNA Circles in the AncestryDNA database. The birth location of each ancestor of a DNA Circle is indicated as a green dot.

In other words, most ancestors who have DNA Circles are people who left a lot of documented descendants living in the United States today.  That’s because most AncestryDNA customers live in the U.S., and in order to have a DNA Circle, an ancestor must have left many descendants – at least three of whom have independently taken an AncestryDNA test. Furthermore, given that the average DNA Circle ancestor was born in 1800, descendants of that ancestor must have extended their family trees at least that far back to include that ancestor, too.

With that in mind, it fits that we see a higher concentration of DNA Circle ancestors born in the eastern U.S., where more people living in the 1700’s and 1800’s had enough children to now have many descendants in the U.S. today.  With regards to DNA Circle ancestors abroad, it also makes sense that we see many born in England, Ireland, and Western Europe.  Many ancestors from these regions of Europe migrated across the Atlantic (or had descendants who did), subsequently leaving a lot of U.S. descendants who can now trace their roots back to them.

While these patterns explain the general distribution of DNA Circles across the globe, a closer inspection of the map shows that we also find DNA Circle ancestors in other parts of the world – for example in Russia, China, Mexico, and Puerto Rico.  These diverse origins of DNA Circle ancestors emphasize the power of over 850,000 AncestryDNA members and their family trees to connect us to both our ancestors as well as our living relatives.

Even better than this map of birth locations of DNA Circle ancestors is the fact that every day, the map looks different.  As we expand into new markets, new individuals take DNA tests, and AncestryDNA members build out their family trees, we’ll discover new DNA Circles.  Some of those new Circles may even be centered around ancestors born in places where we’ve never before found one, because we didn’t yet have enough of those ancestors’ descendants tested at AncestryDNA.

These new discoveries will be more than just new dots on the map. Over time, they will allow DNA Circles and their associated New Ancestor Discoveries to connect even more individuals, with diverse family histories from around the globe, to their ancestors and distant relatives.  That too is something to celebrate on DNA Day.

In honor of DNA Day, AncestryDNA is extending 20% off AncestryDNA kits thru Monday, April 27th. To learn more and purchase an AncestryDNA kit visit here.

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Celebrate DNA Day with Your Own Discoveries Fri, 24 Apr 2015 20:42:05 +0000 Anna Swayne Read more]]> DNA Day comes every year, April 25th and it’s a great time to celebrate the amazing discoveries we’ve made about the human race. It’s also a great time to make a few new discoveries of your own. In honor of DNA Day, now through Monday, we have a limited time offer to get 20% off the AncestryDNA test. To take advantage of this great deal, click here.

We’d also like to share a new way to learn about DNA. Last week we announced the launch of Ancestry Academy. It’s a new educational website that offers exclusive, high-quality video courses taught by genealogy and family history experts.

Among the many topics being covered, we have an entire section on DNA. Want to know why you should take a DNA test, what you get from a DNA test, or what you do with all the cousins you’ll find? Drop by the Academy. Start from the beginning of the course or take five minutes and watch a video on “Genetic Inheritance” and learn how your DNA results can be different than a sibling’s. The best part is you can access this DNA course for free.  Each topic is broken up into 2-5 minute videos and there are several to choose from. Click on the video below to get a preview of the course, and then go sign into Ancestry Academy and start exploring today.



Take time on DNA Day to learn about the power of DNA and how it can unlock the stories of your past. If you haven’t taken a DNA test, see how easy it is to take the test (watch the ‘demo’ video to get the tips and tricks) or how to buy a DNA kit online. This DNA 101 course is just the beginning of many other courses around DNA so stay tuned. We will let you know when new material is available.

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AncestryDNA Gives Me a Sense of Self Fri, 24 Apr 2015 09:29:03 +0000 Jerome de Groot Read more]]>  

Intl_UK_DNA_250x250_BadgeI’m just about to undertake a DNA test. I’m both terrified and exhilarated about what it might find. DNA testing for genealogy is a powerful tool, and is gaining attention at the moment. DNA sequencing makes the subject of your investigation – your own cells, the stuff inside you. It is inescapable and accurate.

Ancestry have just launched the service in the UK & Ireland. What does it actually mean to do it? Does it change your life?



I am an academic. I am a scholar. I write about things, I don’t do them! So what am I doing spitting in a test tube and sending it off for analysis? Why am I having my DNA sequenced for genealogical purposes? What will it change in me, if anything? DNA sequencing promises something final, a set of data that is not negotiable. It makes historical research like genealogy into something scientific. It takes research out of the archive and into the lab.

Having this kind of personal interest in your research is a very new thing for me. I am literally putting my research money where my mouth is. Yet I have decided to do this for a number of reasons.

I can hardly talk about the way that this kind of approach affects you if I have not done it, can I? I need to understand the strangeness that this might create in a sense of self. I need to experience how those who undertake DNA tests feel about the results. I need to know whether they do change their way of defining themselves.

I first spoke on this subject in Amsterdam, which is the city my Opa (Grandfather) was born in. He was a somewhat distant figure to me and I walked the streets and canals wondering if I could somehow gain a connection or an insight into this strange man who spoke with a thick accent and whose eyebrows were astonishingly bushy.

Can I get closer to him? Will DNA testing throw up some kind of shock, something that I hadn’t known, something I didn’t want to know? Would it change me?

I am interested in the blending of body and archive that is now happening on Ancestry. In my work I look at the way that the human body is becoming part of historical investigation, and providing evidence for family historians. How does DNA data change our way of understanding the past? We generally understand DNA through popular scientific versions of genetics, or through paternity tests undertaken on the Jeremy Kyle show. It is a promise of revelation – good and bad. This was shown powerfully recently when White Supremacist Craig Cobb discovered on live television that he was 14% African American.

Yet I guess the point is that the DNA information lies there whether we access it or not, whether we leave it dormant or begin to start looking at it. It offers a new way of understanding the huge, terrifying thing that is the past.



The process of collecting DNA is a bit of a faff – spitting in a tube, shaking it about. I’ve just done some exercise so I have hardly any saliva. It certainly does not feel like ‘research’ or that I am engaging in some kind of important journey. It is an anti-climax! I forget about the whole thing until an email pings into my inbox suddenly. I am scared to open it….

Have I changed?

My ethnicity is pretty much what I had expected, and it is very solidly European. I’m 40% from Great Britain, 28% from West Europe and 15% from Ireland. This is all kind of predictable for me – I have maternal great-grandparents from Ireland, and my Opa, as I’ve said, was from the Netherlands. The test confirmed what I knew from my own research into my family conducted along more traditional – archival, textual – lines. It confirms that I am incredibly European, and I’m not too surprised. My 6% Italian DNA allows me to follow, for instance, my maternal great-great grandfather, the Merchant Seaman from Genoa, through my physical physiology and also my archival family tree. I have a sense of the past as something found in documents but also residing in my innermost cells.


I have, though, got little bits of other things that I can’t identify as easily. 6% is from Finland/ Northwest Russia. 3% is from the Iberian Peninsula, and a final 1% is from Scandinavia. These are more problematic to find in the physical archive, and perhaps they are multiple generations ago. I like the fact that it is such a mix, and that there are these strange little bits of me that come from all over the edges of Europe.

In some ways it demonstrates powerfully how, in a contemporary world of great mobility, migration and displacement, many of our ancestors did not move or travel a great deal outside of Europe.

The DNA data confirms my sense of my self in some way. In terms of new family, I have some interesting connections. My nearest DNA matches is a 4th cousin. That Italian great-great grandfather is the link between us. I find it amazing and strange that there is someone living who shares some of their basic cellular information with mine. It doesn’t change my sense of my family but it alters my sense of singularity somehow. It opens up a new sense of things. These DNA matches – to 4th, 5th, and even 6th cousins – can be very useful in making research breakthroughs.


You can follow Dr. Jerome de Groot on Twitter @deggy21

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AncestryDNA is a Team Sport Thu, 23 Apr 2015 21:59:05 +0000 Mike Mulligan Read more]]> When I first took the AncestryDNA test, my friend Anna asked me if I had tested any other members of my family. At the time I remember thinking very clearly that I already had hundreds of matches, the last thing I needed was more matches. Fast forward a few months and my Dad mentioned he would like to do the AncestryDNA test. So as a birthday present I got him an AncestryDNA kit and he took the test. A few weeks later his results came back and he was very happy with the outcome. However for me it turned out to be one of the smartest things I’ve done since I originally took the test. Now when I get a match that’s also a match of my Dad I also know which side of the tree that match is on. It gets much easier to work out the shared relationship. I only have to compare our common match against half my tree.

I asked our ever helpful science team at Ancestry if they could tell me just how much of a benefit I get using both my test and my Dad’s. It turns out that with my test alone, the chances of matching a particular 4th cousin in the AncestryDNA database is about 71%. The reason for this is simply that each of us get different bits of DNA from our ancestors and by 4th cousin relationship there is a bigger chance we simply won’t match. But having both my test and my Dad’s test that number increases to 89%, much better odds. Not only that, the 89% is on Dad’s side of the tree. So I get a better chance of finding my 4th cousin but also more precision in working out a common ancestor.

That got me thinking of who else I should try to recruit on my cousin finding mission. Ask my sisters perhaps? Or should I try and get some of my cousins to test, particularly those who are on lines where I have brick walls. The answer to my question is shown in the image below.

Testing with family members

If I was to get any of my sisters to test it would boost my cousin finding rate from 71% to 83%. That’s certainly an improvement, but if I could get a grandparent to test that would increase my success rate from 71% to 98%. That 98% would also be in a specific quarter of my tree. This would be a huge increase in the success rate but also an increase in the precision because I am able to narrow down the match to my grandparents branches. I have no living grandparents, but I do have two grand aunts on different branches of my tree who are now top of the list of people I want on my cousin finding team. But what about my 1st cousins? I had considered asking some of them to test. Certainly it would increase my chances from 71% to 87%. But if I ask an aunt or uncle instead that number goes to 94%. And again, if both of us have the same match I can narrow it down to a specific half of my tree.

Like many of us researching our family tree I have spent many hours alone quietly in in libraries and archives poring over census documents or birth records. If there is one thing I’ve come to realise about doing my family history with AncestryDNA it’s that it is very much a team activity. The more people I can get on my team the better the results for all of us.


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Exploring our DNA – Europe West Fri, 10 Apr 2015 10:00:39 +0000 Mike Mulligan Read more]]> Our Western European DNA
When I was a child my grandmother used to tell me how her family descended from Black Forest Quakers who fled to Ireland to escape religious persecution in Germany in the 1700s. Like all the best family stories there was a kernel of truth, as I would later learn about my Palatine ancestors. I’ve often wondered what life must have been like for the 13,000 German refugees camped out in Camberwell and Blackheath in the summer of 1709 with no idea what future lay in store for them. I was reminded of this recently as I was looking at a map showing Europe West ethnicity estimates across the UK & Ireland.


Europe West is one of the 26 global regions that we have built up using a group of individuals known as our AncestryDNA Reference Panel. The region geographically spans France and Germany but also takes in several other countries including the Benelux countries, Austria, Switzerland and parts of Denmark, Poland, Italy and the Czech Republic. A common question we get asked is why such a big area? Is it not possible to  tell French from German? The answer is that the people in this region moved around a lot and mixed with each other and with those from neighbouring regions. The term we use for this is admixed and the people living in the Europe West region are among the most admixed of all of our regions.


Europe West and Great Britain
The map above shows average Europe West ethnicity estimates of those who have taken the AncestryDNA test and were born in the UK and Ireland. It does not use any historical migration data; it is based only what is in our DNA. So, for example, I was born in Dublin and my Europe West estimate is 1%. On the other hand my friend Bryony, from Berkshire, has an estimate of 45%. When you average the Europe West ethnicity across the thousands who have taken the AncestryDNA test in the UK and Ireland you end up with a map like the one above.


The distribution of Europe West ethnicity goes from a high of 26.84% in Kent to a low of 11.28% in Scotland. Broadly speaking the average ethnicity decreases smoothly as you spread out from the Kentish coast, but there are exceptions. London is lower than the surrounding regions. This is common in London as it is a very diverse area with a wide range of ethnicities. One of the biggest surprises we often see when people get back their results is just how high their Europe West estimate can be. It should be remembered that the estimates show influences of ancestors 500-1000 years ago. Your paper trail may go back 300 or 400 years showing all English ancestors. But your AncestryDNA ethnicity estimate is taking you beyond that and hinting that their ancestors in turn may have had Western European heritage.

The Europe West estimate for Wales and Scotland is lower than for England, as we might expect. The ethnicity estimate for Southern Scotland is actually lower than Northern Scotland. Once again we are perhaps seeing the connections reflecting the close history of Southern Scotland and Ulster.

Europe West and Ireland
The picture in Ireland is somewhat simpler. There is a fairly low level of Europe West ethnicity across the country reflecting less inward migration from continental Europe. We do see Ulster being slightly higher than the other provinces of Ireland, mirroring the figure we saw in Southern Scotland. We also see Connacht showing the lowest average Europe West, again reflecting the low level of inward migration over the centuries.

What we don’t yet see in the provincial breakdown is potentially higher Europe West ethnicity in the South East of Ireland reflecting the Norman influence on that part of Ireland. Our initial trial did show individuals from Wexford and Carlow with higher Europe West than others on the trial. We don’t yet have detail at county level that would enable us to see if that is a result that holds in general. euwest4

People have been migrating across the channel to Britain for many thousands of years. From the Angles and the Saxons. From the Jutes, the Frisians and the Franks. All the way to the Normans, Huguenots, and Palatines. They have all come and become part of the tapestry of the British and Irish peoples. And now through modern science and AncestryDNA we can see that they have also become part of the tapestry of our DNA, part of the very essence of who we are.

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New Ancestor Discoveries: Clues (Not Proof) to Your Past Thu, 09 Apr 2015 18:13:03 +0000 Kenny Freestone Read more]]> Last week we announced an exciting new AncestryDNA feature called “New Ancestor Discoveries.” The response to this feature launch has been very interesting to watch—we’ve received lots of feedback breathless with praise because we “proved” a relationship, and some feedback that dismisses the feature because it does not “prove” relationships. As we consider feedback from both of these extreme positions, it seems appropriate to explain more clearly what this feature is and is not.

What is a New Ancestor Discovery?

  • What it is: A New Ancestor Discovery is a suggestion that points you to a potential new ancestor or relative—someone that may not be in your family tree previously. This beta launch is our first step toward an entirely new way to make discoveries, and a way to expand how we do family history.
  • What it isn’t: This is not proof, or a guarantee, of a new ancestor. They’re called New Ancestor Discoveries, and many may be your actual ancestors. Some will be other relatives that fit somewhere on your family tree, and some will be people that you may not be directly related to.
  • It’s a starting point to further research. We’ll show you a New Ancestor Discovery if you share significant amounts of DNA with multiple members of a DNA Circle—which means you might also be related to the ancestor that the DNA Circle is built around. These hints can be a great starting point for your research and help you connect to other family members you didn’t know you had.

Why do we think you are related to this person?

  • The short answer is that we don’t know for sure. What we do know is that you share significant amounts of DNA with others who are likely descendants of the ancestor, which leads us to believe that there is a good chance this person could also be either your ancestor or a relative.
  • When considering if you might be related to a potential ancestor or relative, we combined several pieces of information to make that determination: the number of people in the DNA Circle with whom you share DNA, the amount of DNA shared with each DNA Circle member, the number of generations back to the ancestor for each individual in the Circle, and our confidence that you and each member of the Circle share only one common ancestor.
  • The number of members of a DNA circle that you match directly influences how strongly you appear to be a descendant of an ancestor. Also the size of the DNA Circle (in terms of the number of members) can also influence how you interpret your confidence in the potential relationship. A small group of say 3 – 5 members might potentially grow in size as more people participate in the DNA test, but should be considered as an emerging evidence of a genetic relationship until it grows further.
  • A New Ancestor Discovery is created as we detect that you share significant amounts of DNA with several members of a DNA Circle—which means you might also be related to the ancestor that the DNA Circle is built around.

What is the confidence you are really related to this person?

In general, the confidence that a New Ancestor Discovery really fits in your family tree is pretty good—about 70%. However this can vary in each individual case. Also it is important to understand that while some New Ancestor Discoveries lead to a direct ancestor, some suggested ancestors end up belonging in your family tree as a collateral line relative, and some won’t be closely related to you at all—but they likely lived at the same time and place as your actual ancestors so they could be a helpful clue to point you in the right direction.

In addition, the ratio of new ancestor vs. collateral line relatives can vary based on how many DNA Circles you are already connected to through your family tree. We find that people who have stronger family tree connections (and so generally have more connections to DNA Circles) will see a much larger proportion of collateral line relatives or suggested ancestors that don’t clearly fit in your tree, but lived at the same time and place as your actual ancestors. The reason for this is that when you have an extensive family tree, we typically have already identified your direct ancestors in a DNA Circle.

Because of all this, it is important to apply traditional family history research methods to each potential ancestor suggested by a New Ancestor Discovery in order to determine more specifically how you might be related.

Expected frequency of different types of new ancestor discoveries. A: Hint for direct-line ancestor about 50 percent of the time (for a user with no tree). B: Hint to a circle where you share multiple common ancestors with other members about 30 percent of the time. C: Hint for collateral-line relative about 20 percent of the time. Note that for users with large trees and many direct-line DNA Circles, B and C may be more frequent.

Expected frequency of different types of new ancestor discoveries. A: Hint for direct-line ancestor about 50 percent of the time (for a user with no tree). B: Hint to a circle where you share multiple common ancestors with other members about 30 percent of the time. C: Hint for collateral-line relative about 20 percent of the time. Note that for users with large trees and many direct-line DNA Circles, B and C may be more frequent.

How is the confidence determined?

To determine this confidence percentage we performed tests of our algorithm on a massive set of DNA tests where a nearly-complete and deep pedigree is known. We remove each individual’s pedigree data in our analysis and find New Ancestor Discoveries for each DNA test. Then we look again at the pedigree information we previously ignored and compare what New Ancestor Discoveries we found versus what actual ancestors exist in the pedigree, and what collateral-line relatives are observed. This analysis gives us confidence that, in general, if you have an empty family tree, the ancestors and relatives we suggest in this process are likely to belong in your family tree as a direct ancestor or as a collateral-line relative about 70% of the time.

An exciting journey of discovery

We are very excited about the many family history discoveries that are being made now and will be made in the future as the New Ancestor Discoveries feature continues to grow and improve. Please keep sharing your feedback with us — we are definitely listening. And if you haven’t taken the AncestryDNA test yet, now is a great time to begin.


Related Posts

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The Interconnectedness of the Human Family Wed, 08 Apr 2015 12:00:19 +0000 Ancestry Team Read more]]> By Henry Louis Gates Jr. and Julie Granka, Ph.D., Population Geneticist for AncestryDNA

I am taking part in the DNA test from Ancestry because it is going to be super exciting just to find out my ethnicity. Is there anything I can do that would help me locate possible living relatives? Thanks for your time!   —Thomas

Dear Thomas,

It used to be that the only way to find long-lost relatives on our family tree was to follow the paper trail.  And unless your ancestry connected to early American colonists or to European royalty, it was very difficult to find paper documents older than the last few centuries.  And what about your relatives who didn’t leave a paper trail?  In the past, these ancestors were doomed to disappear.  But not any longer.  Now we can locate both ancestors you never even dreamed that you had, plus cousins of yours who are alive today—all by taking a simple and inexpensive DNA test!

Some of us were born into large nuclear families. And some of us could hold a family reunion around a kitchen table without even adding any extra leaves.  But regardless of how many brothers and sisters, aunts, uncles, and first cousins you might have, your extended family—the people with whom you share recent ancestors over just the last few hundred years—is enormous, far larger than most of us realize.

This is where genetic testing is so valuable. By identifying your distant cousins who are alive today, genetic genealogy tests can dramatically lengthen your dining table—and enable you to invite to your family reunion some surprising and totally unexpected relatives. Simply by taking a test, odds are very good that you will find additional family members, especially as genetic databases grow. Here’s why.

You have a lot of distant cousinshuff po

Let’s start with a little, simple arithmetic.  (Don’t panic; it’s just multiplication!)  If each of the ancestors in your family tree had 2.5 children (on average), you’d have about eight first cousins and more than 110,000 seventh cousins.  In other words, your seventh cousins alone could make up the entire population of Berkeley, California, or Ann Arbor, Michigan! And if your ancestors averaged four children instead, you’d have over 6 million seventh cousins—more than two Chicagos.

This is not just an astonishingly impressive statistic. Just think: if every one of the 300+ million people currently living in the United States each had their own separate, distinct, Berkeley-sized circle of relatives, you’d run out of living people!  And this means, if you think about it, that we all must share living cousins—our sets of relatives have to overlap.

Of course, the 7 billion people populating the earth today are all connected through our common human origins back in Africa a long time ago, but we’re linked more closely and more recently through the exponential growth of human populations over the last several centuries.

You have a lot of ancestorsand you share those ancestors with others

huff po 1We can illustrate this with a few more numbers.  The number of ancestors (or branches) on your family tree doubles with each generation. If you keep going back from your two parents, your four grandparents, and your eight great-grandparents, you’ll find that just over 400 years ago or so, you have more than 100,000 ancestors. And so does the person sitting next to you on the train or bus this morning, or standing next to you in the elevator. Is your distant cousin right beside you?

Do any of your ancestors overlap with the ancestors of any of these total strangers? In other words, do you and your fellow passengers have any overlapping names on your separate family trees, which would mean that you two are related?

The answer just might be yes.  That’s because there are two mathematical forces at work here. As you look back in time, you have more and more ancestors, because the number is doubling each generation back in time; but the pool of ancestors you could be related to actually gets smaller and smaller, and that’s because the total human population was so much smaller back then. (The world’s population has been steadily growing since those people on the upper branches of your family tree were alive.)

That means the further you look back in time, the more likely it is that you and that random person on the subway or in the elevator share an actual ancestor!  It’s fascinating, isn’t it?

As an example, fewer than 3 million people lived in the American colonies before the Revolutionary War, compared to more than 300 million today. So if you and a total stranger both had ancestors living in Colonial America, you might actually share the same person on your family trees, simply because there weren’t that many people around back then. And while you’re less likely to find that common ancestor so easily if your fellow commuter hails from Shanghai instead, you just have to look further back in time to find a link even with them.

Genetics confirms these connections

With genetics, we see this interconnectedness of the human family move from a mathematical formula to reality, from statistical probabilities to the identification of actual individuals that you share in common with another person’s family tree.

Genetics allows us to turn a theory into ancestry.

In addition to providing an estimate of where your ancestors once lived and when, genetic genealogy companies identify your potential relatives by looking for other test-takers who share identical stretches of DNA with you. If two people share a long stretch of DNA, it’s likely because they inherited that DNA from the same ancestor; in other words, because they’re related.  And often, these shared ancestors lived in the last 500 years—since the time of Columbus—which in human history is a bit like yesterday.

How many relatives could you find?

Even without a researched family tree, a DNA test can connect you with hundreds or even thousands of living relatives whose DNA was automatically matched against yours in the testing database. And the number of relatives you could find grows daily as genetic testing databases get larger.huff po 3

For example, when only 100,000 people had taken an AncestryDNA test, the average test-taker found about 20 fourth cousins in this database. Now, with more than 800,000 participants, a person finds on average 150 fourth cousins.  In other words, each new person who takes a DNA test could be a long-lost relative!

So far, AncestryDNA has connected more than 60 million pairs of fourth cousins—more pairs of fourth cousins than there are people in California and Florida combined. (This is even more impressive when you compare that number to only 22 million pairs of fourth cousins that we were able to identify when the database was just half its current size.)

Even though the AncestryDNA database primarily represents people in the United States, what we know about human history tells us that other populations are just as interconnected. And to a lesser degree, this interconnectedness spans continents because of our common human origins back in Africa and the manner in which those original ancestors colonized the world.

More than just numbers

Genetic testing has been expanding those family reunion dining tables by the day—and some tests have led to discoveries with huge personal impact.

For example, in an earlier post, we told the story of an adoptee who found an unknown second cousin—and eventually met his birth family. Kevin Bacon and Tina Fey were astonished to learn, as guests on Finding Your Roots, that they were distant cousins, because they share a long identical segment of DNA on chromosome 20.  And though they look nothing alike, Jessica Alba and Alan Dershowitz are also distant cousins, sharing an identical segment of DNA on chromosome 7.  We were also able to find the identity of Derek Jeter’s third great-grandfather, who fathered a child with a female slave.

Even if we can’t explain the connection through two people’s family trees, long shared segments of DNA are not random; the tests reveal an ancestral connection, and that is one of the most exciting practical applications of modern genetics for those of us in search of our roots.

As all genetic testing databases continue to grow, life-changing, personal discoveries are becoming more and more common. And in aggregate, these genetic relationships—which science only recently could prove—will continue to reveal more mind-boggling statistics about the connections between all of us: how much human history, and how much of the human family, we all share on the branches of our own family trees.

Do you have a mystery in your own family tree?  Or have you wondered what family history discoveries you could make with a DNA test? Send Henry Louis Gates Jr. and his team of Ancestry experts your question at

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Member Spotlight: Family Folklore Proven True with AncestryDNA Fri, 03 Apr 2015 20:00:53 +0000 Jessica Murray Read more]]> Most families have interesting stories handed down over the generations. Ancestry member Heidi had heard stories of a baby given up for adoption at birth because the child’s father, her cousin, and the mother were young. She learned her aunt, the baby’s grandmother, had been searching for the child for years, but had little to no information to work with so her efforts always resulted in dead ends. Until, AncestryDNA.

Heidi received a message via Ancestry’s messaging center that made her quite curious. She shares the story with us below:

What was your inspiration in researching your family history?

Heidi: My inspiration to start researching my family history was the fact that I do not have any children of my own and really felt like I wanted to leave my mark on the world. I also enjoy a good mystery and there is nothing more satisfying than solving a family tree mystery.

How would you describe your level of personal family history knowledge before getting started on Ancestry?

Heidi: Before joining Ancestry, I had a very basic knowledge of my family tree. My maternal grandfather had done a lot of research back in the 1970s and I had access to his notebook and pictures. My paternal side was more of a mystery for sure!

How many years have you been working on your family tree? 

Heidi: I have been working on my personal tree for over 5 years.

What has been the biggest mystery or brick wall you’ve encountered or are currently working on solving? 

Heidi: The mystery and most exciting story to come out of my research is still unfolding. I had taken the AncestryDNA test, but never had any matches closer than 4-6th cousins. It was always fun to connect with distant relatives.

One day, about a month ago, I had a message from someone who said my DNA was showing up as a 1st or 2nd cousin match! Her name was not a name I had ever heard before in my family. We started corresponding and figured out that she must be related somehow on my paternal side. She was adopted as a baby in 1965 and while she knew she was adopted, she had no information at all on her birth parents. We collaborated via email and phone calls, talking late into the night, excited to find where this news would take us. She said she just wanted to let her birth family know that she had a wonderful life and to try to find any medical information since she has children.

I contacted several of my late father’s living siblings to see if any of them knew of a baby being born and given up for adoption. The information I received was that one of my 1st cousins had fathered a child when he and the birth mother were 17 years old and that the mother’s family made her give the baby up. The baby’s father was killed in a terrible motorcycle accident when he was 24 years old. My aunt had also passed away. We could not find the name of the mother. Several relatives were sure it was one person, others were sure it was a different woman, and we actually have three viable possible mothers at the moment. Two of the three possible mothers are now deceased. My “new cousin,” Anne has just this week submitted a request to have her birth records released. So now we wait!

What were the reactions of your family members when you shared the information you discovered?

Heidi: Everyone in my family is so excited to hear how the story of “the baby” turns out and to get to know our newest relative. This is one of the most exciting things to ever happen to me!!

We are pleased to see Heidi and her new cousin Anne explore this path together and wish them all the best as they continue to unravel this mystery.


Have an Ancestry member success story? Share it with us by visiting and you may be featured in a future member spotlight. 


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