Posted by Julie Granka on February 19, 2014 in AncestryDNA

Written records have detailed the varied histories of human groups over the past few thousand years.  While some groups remained isolated, other groups spread far and wide across the globe.  When they did, they encountered and “mixed” with other human groups – mixing both their people and their DNA.  That history has left its signature in present-day DNA.

At AncestryDNA, this signature is what enables us to examine your DNA to give you a clue about your own ancestral origins – the human groups that have been a part of your family’s history.

In new scientific research at the University of College London and Oxford University, DNA alone was used to create a comprehensive atlas detailing which human groups may have mixed their people and DNA over the past several thousand years – and when.  Using DNA from people from almost one hundred contemporary populations across the world, the researchers identified when in history certain human groups may have mixed with others.

AdMixing DNA Screenshots
A genetic atlas of human admixture history

In some cases, the estimated dates match up remarkably well with what we know from our history textbooks.  For instance, patterns of DNA in Central Eurasia support the 13th century spread of the Mongol Empire led by the infamous Genghis Khan.  The researchers also find DNA evidence of European and African mixture into the Americas in the 16th century during the Colonial Era and the Spanish conquest of the Maya.  In research at AncestryDNA, we’ve identified similar evidence of European admixture into Latin America.

The exciting thing about this latest study is that by using a new sophisticated method that looks at patterns in chunks of DNA in present-day human populations, DNA itself has put accurate dates on these mixing events.  The method may even help to uncover events that aren’t recorded in written history.  And, the researchers have created a cool interactive map to present their findings.

We’re inspired by the new scientific research coming out of the University of College London and Oxford University because it shows the incredible potential of DNA research.   While history can inform our interpretations about patterns in DNA, DNA also can shed new light into history.

At AncestryDNA, we’re working hard to develop and use our own advanced methods to help you discover even more about your own history.




Julie Granka

Julie has been a population geneticist at AncestryDNA since May 2013. Before that, Julie received her Ph.D. in Biology and M.S. in Statistics from Stanford University, where she studied genetic data from human populations and developed computational tools to answer questions about population history and evolution. She also spent time collecting and studying DNA using spit-collection tubes like the ones in an AncestryDNA kit. Julie likes to spend her non-computer time enjoying the outdoors – hiking, biking, running, swimming, camping, and picnicking. But if she’s inside, she’s baking, drawing, and painting.


  1. June Fairhurst Fay

    Nice to see article depicting the migrations of differents peoples over time.
    I recently received my DNA from Ancestry, awaiting my husbands results.
    What I found that was particularity interesting was the depiction of the patterns of migration within my own results. The map which accompanied the results, was done in such a way to illustrate in “overlap” fashion, showing the paths in which they probably travelled.. Great use of a “common sense” concept…

    This will indeed add to timelines, that may not exist, rethinking many of the previous held paradigms. It great to be part of an evolving science..
    Thank You Ancestry

  2. arlene miles

    Thanks for sharing this interesting information from London and California.
    I would like to see a list of books on populating the earth and migration of people the you and your scientific team could suggest for further reading .

  3. Sally Johnson

    I have a question about the map, but I can’t afford the $20 to buy access to the full article. I’m hoping you may be able to help me, since you’ve read it. My background is primarily Swedish, and I was surprised and disappointed to see that they haven’t included the Swedish population on their map. This despite including some very small, relatively unknown populations. Do they give data for the Swedish people in the article? Are we to assume that the Norwegian data covers the Swedish people as well? I’d be surprised about that given some very likely differences – for example, Finland was a part of Sweden for a very long time, with a lot of interactions and intermingling. A stronger Finnish effect (reflecting the populations that have mixed into that group) on the Swedish population would be almost inevitable, compared with the Norwegian, since Norway wasn’t a part of that union and is geographically removed from Finland. Is there any help in this project for us who are seeking this kind of long-span background on the Swedish people?

    Thank you so much for readin and considering my question.

    Sally Johnson

  4. Ashley Bens

    Sally, unfortunately the way this research works makes it harder to distinguish populations that we are often looking for. Countries are modern constructions, and so it may be near impossible to differentiate between countries where there was much intermingling or are very closely related. This happens in Scandinavia, Germany and France, and Spain and Italy. When you consider how old your DNA is, researchers have to ask if the inclusion of a marker belongs to the original population, or if it came into the population later, albeit in antiquity. Consider Italy as an example. What is a native Italian? They could be Etruscan, Sicel, Italic, Umbria, etc. Later, groups such as the Greeks and other Mediterranean cultures moved into the area we think of as Italy. Even later, we see the goths come down and take over Rome. This is all before the Middle Ages. So what markers would you look for in an Italian? Areas prone to invasions or crossroads have this problem.

    The reason that unheard of populations are easy to map is because of their genetic isolation. Jewish DNA may represent only 1% of human DNA, but it is so easy to distinguish from other populations. Now that we know what Jewish DNA looks like, we can more easily trace the diaspora. Consider this with other populations. Once researchers can tease apart Swedish, Danish, and Norwegian, they can give better estimates of DNA admixture. The problem lies in sample sizes, and finding out what makes each population unique.

    Be patient, they will get there !

  5. Justin

    Hi Julie I am hoping you can recommend some reading for me – I don’t really have a background in genetics. I have friends who are very enthusiastic about genealogy projects, but despite all of this great technology and efforts they seem to think there are real scientific boundaries to different populations that they think go back to the beginning of time. My intuition is this is not correct – we all have a common ancestor (or common group of ancestors but the group was so small it is functionally one point in time) and any classification of their descendants into separate groups – whether self defined or not – is ultimately contentious. That just seems like common sense! I am really hoping you can recommend some reading material so that I can develop a little more sophisticated appreciation about how people talk in a scientific manner about ‘populations’. I really don’t want a naive perspective here… I worry that my peers interest in genetics is perpetuating essentialist ideas about groups, if you will, and I don’t have the experience to talk about this properly. Thanks JTurner

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