Every family has its legends. Maybe it’s a story about how they’re descended from a passenger on the Mayflower, a Confederate soldier or Charlemagne.

Of all the classic American family legends, stories of a Native American ancestor are among of the most common. Many times there’s a well-documented link to a Native forbear: Two First Ladies (Edith Wilson and Nancy Reagan) and one Duchess of Windsor (Wallis Simpson) are proven descendants of Pocahontas.

Other times, the evidence amounts to little more than vague tales about a rugged pioneer and a Cherokee princess. (Learn what’s wrong with that scenario here.)

Now 23andMe customers who are curious about whether they may have Native American ancestors can look for evidence of it in their genes. The Native American Ancestry Finder uses some existing 23andMe features — Ancestry Painting, Maternal Line and Paternal Line — to look for genetic signatures that are likely to have come from a Native American ancestor.

The Maternal Line and Paternal Line elements of the Finder are pretty straightforward; certain mitochondrial DNA (maternal) and Y chromosome (paternal) haplogroups are often found among Native Americans. These include mitochondrial haplogroups A2, B2, C1, D1 and X2a — which are found exclusively among Native Americans. People in some other branches of the A, B, C and D haplogroups may also have Native American ancestry, but their maternal lines could also trace to Asia. On the paternal side, only Q3 is exclusive to Native Americans, though anyone with a Y chromosome in the C, C3 or Q haplogroup could conceivably have Native American forbears.

A Native American’s Ancestry Painting.

The part of the Finder that uses Ancestry Painting to find evidence for Native American forbears is a little more complicated. It relies on the fact that people of full Native American descent have Ancestry Paintings that are consistently about 75% orange (Asian) and 25% blue (European). This is due to the fact that Native Americans are ultimately descended from populations that lived in northern and central Asia about 15,000 to 20,000 years ago, and the fact that those regions are intermediate between the reference populations that Ancestry Painting classifies as fully Asian (Japanese and Chinese) and fully European (European-Americans living in Utah).

Then the Finder compares your Ancestry Painting proportions to a table that contains the results of an extensive series of simulations that we performed to determine what would happen to that three-to-one Asian/European proportion over the generations if a Native American and a partner of all-European descent had a child who then reproduced with another all-European partner, and so on. We did the same analysis for a Native American marrying into an all-Asian pedigree. Unfortunately, partly due to inadequate sampling of Africa’s genetic diversity, this method cannot yet establish Native American ancestry for African Americans.

We found that it takes at least five generations after the appearance of a single Native American in an otherwise all- European pedigree for the percentage of Asian (orange) DNA to reach zero. In an otherwise all-Asian pedigree that process is much faster — in two generations, the grandchild of that single Native American can have no trace of European in his or her Ancestry Painting.

There are, of course, plenty of Eurasian populations that also have blue-and-orange Ancestry Paintings. So the Native American Ancestry Finder performs a second analysis that can distinguish people of South Asian, Central Asian, Middle Eastern and Ashkenazi descent from those with Native American ancestry. Unfortunately, there is still some uncertainty when it comes to distinguishing people with Native American ancestry.

It’s still a work in progress — that’s what Labs are all about. But we hope customers will help us by trying out the Native American Ancestry Finder and letting us know if anything doesn’t mesh with what they know about their genealogy. You can also contribute by taking the “Where Are You From?” survey in 23andWe.

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Andro is 23andMe’s science and policy liaison. His main responsibility is to monitor opinion in policy, regulatory, academic, and other stakeholder circles, and to integrate this feedback into 23andMe’s product and internal procedures. Recently, he worked on 23andMe’s successful application for a California clinical laboratory license.

Andro on the 23andMe Service:
“My father was born in China and my mother was born in the Philippines, so you’d expect my Ancestry Painting to look all orange (i.e. Asian). But I actually have a a few blue European stretches, especially on chromosome 6. As a scientist, my first instinct was that this must be statistical noise, but my mother has the exact same stretch of blue, in addition to a few others. It turns out that my mother has a Spanish ancestor some generations back, so it’s possible that just by chance, a bit of my European ancestor’s DNA has survived the many meiotic recombinations between us and made it into me.”

Andro on Being a 23andMe Employee:
“After finishing my PhD in molecular and cell biology, I came to 23andMe as its first science writer. 23andMe interested me because it was at the forefront of both genomics and social networking–two areas that had not yet been mixed successfully. What’s most exciting about a disruptive new innovation like 23andMe’s genotyping service is that we get the chance to shape how the field of personal genomics will grow over the next few decades.”

“Education is another reason I joined 23andMe. Genetics is much more complicated than one gene = one trait, even though there are plenty of examples where a single gene does determine a trait (like earwax type). But here at 23andMe, we believe that by giving customers their own genetic data, they will be much more invested in learning about the latest scientific research in an informed way.”


Think you’d like to join our team? Check out our jobs page!

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Now Roy has another genetic puzzle to consider – himself. With the help of 23andMe, he can now see how his own family tree – which has African American, Native American and Ashkenazi Jewish branches – is reflected in his genome.

Roy recently sat down with some of 23andMe’s scientists to look at his Ancestry Painting. (You can watch video of his conversation with 23andMe’s Matt Crenson below.)

An element of our Personal Genome Service, Ancestry Painting examines the 22 bi-parentally inherited chromosomes one segment at a time and determines for each stretch whether it was most likely inherited from ancestors in Africa, Europe or Asia. Roy’s painting is one of the most colorful our scientists have ever seen – an intricate patchwork of blue, orange and green. The colors indicate which segments of Roy’s DNA he inherited from ancestors in Europe, Asia and Africa respectively.

Though the pattern may look random to the untrained eye, it actually reveals a wealth of information about Roy’s ancestry. It also confirms a lot of what he has discovered in researching his genealogy.

For example, Roy has found records indicating that two 19th-century ancestors on his mother’s side were Native American. The orange stretches in his Ancestry Painting support that account. Native Americans tend to have predominantly orange paintings, with a smattering of blue indicating their descent from Ice Age hunters who lived in Siberia, a part of Asia with some European genetic influence.

According to Roy’s family tree about one-quarter of his ancestry should trace to Europe, because his paternal grandfather was an Ashkenazi Jewish man from New York City. His other three grandparents were African American.

So why does his Ancestry Painting indicate 51% European ancestry, rather than something closer to 25%?

The reason is that like most African Americans, Roy has some European ancestry from the pre-Civil War era. Roy’s genealogical research suggests, for example, that his great-grandmother may have been the daughter of a white man who raped his great-great-grandmother. Another of Roy’s great-great grandmothers came from New Orleans, where research has shown that the African Americans average about 20% European ancestry.

For an illustration of how a person’s Ancestry Painting and family tree match up, take a look at this illustration of Roy’s pedigree.

Instead of labeling each oval (indicating a female) or square (male) with names and birthdates, we’ve given them colors. Green indicates a person who would typically be considered African American, blue a person of European descent and orange a Native American.

There appears to be more green in Roy’s family tree compared to his Ancestry Painting, due to the presumed presence of European ancestry among some of Roy’s African American ancestors. But other than that, the two illustrations of his ancestry look remarkably similar.

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Now, 2,000 generations later, 23andMe is launching a new feature that can help you see the traces of those ancient voyages in your chromosomes. As populations became separated over the millennia, small genetic differences developed that can still be used as signatures of geographic ancestry. Ancestry Painting looks at those signatures in the 22 numbered chromosomes (that is, all but X and Y) to infer where in the world the ancestors who passed you each stretch of DNA were most likely to have lived – Africa, Asia or Europe.

Ancestry Paintings essentially give you a snapshot of where your ancestors lived before the beginning of the colonial era about 500 years ago. That’s because the massive migrations that have occurred since then have blurred many of the genetic boundaries that had developed over the millennia. For example, most Americans trace their ancestry not to the continent where they live but to Africa, Asia, Europe or a combination of those places.

The best way to understand Ancestry Paintings is to take a look at some. For example, this is the painting of a woman who has three grandparents from Germany and one from Norway:

Her painting is nearly uniformly navy blue, an indication that all of her chromosomes come from European ancestors. There are a few brief stretches of orange (meaning Asian ancestry), but in light of the overall pattern it is more likely that the orange stretches are statistical “noise” than indicators of true Asian descent.

Now suppose that woman had a child with an African man. Because each person has 22 pairs of numbered chromosomes – one from each parent – Ancestry Paintings depict both in a single band. So the child of a mother with fully European ancestry and a father with fully African ancestry would have a painting consisting of 22 half-navy and half-green stripes.

It’s in subsequent generations that things really get interesting. For example, this is the painting for a man who identifies himself as African American:

Genetic studies show that most African Americans have at least some European ancestry, and that finding is borne out by this man’s Ancestry Painting. In fact, all the chromosomes are at least half blue, suggesting that this person has one parent of fully European ancestry. The solid blue color in some stretches indicates at least partial European ancestry for the other parent, whereas the stretches that are half blue and half green indicate African descent from one parent and European from the other. The overall fraction of each type of ancestry – African, Asian and European – is tabulated in the legend in the upper right of the display.

Log into your 23andMe account to find many more examples of paintings from individuals from around the world, along with descriptions of the events in human history underlying each and more detailed information about how to interpret them.

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