Posted by Anna Swayne on February 21, 2014 in AncestryDNA

Just the other day, I had a conversation over the fence with my neighbor about family history, and how she could trace her genetic roots back to Africa. Usually, we are talking about how her cats got out, and whether or not I have seen them.

She was intrigued and surprised to hear that you can now trace your roots back to specific regions of the world based on the DNA you’ve inherited. I explained that the science and technology has advanced so much in the last few years that from a simple DNA sample, AncestryDNA now can tell her what her ethnic mix is.

Mary, being almost 90, told me that finding more about her family history is something that she has always wanted to do. Growing up in Alabama, she could only go back so far, and she told me how extremely difficult it can be to research one’s African ancestry using historical records alone. I showed her the map of African regions for which we can estimate someone’s ethnicity, and she exclaimed, “This may be able to help me where the paper trail has ended!”

Mary just sent in her DNA sample, and we are waiting for her results.  Maybe she will share what she finds out with all of you.

african map

This will be an exciting genetic journey for Mary, and potentially many of you.  She may unlock a story waiting in her DNA.

How can AncestryDNA tell you such a detailed genetic ethnicity?

The short answer is that we have an outstanding science team that is doing a lot of research. AncestryDNA’s genetic ethnicity estimate will become even more refined based on the science team’s research and data.

For example, look at the improvements that the AncestryDNA science team has made to our African ethnicity estimates. The pictures below show that only a few short months ago, we estimated an individual’s West African ethnicity as only one region. Recently the science team has split the region into six separate regions.  This means that individuals now can have a finer-grained view of their Western African roots.

This was a breakthrough, and something very exciting for people just like Mary.  Those who believe that their family comes from West Africa will now hopefully be able to explore a country or other more specific region in which they may have ancestry.

before and after of africa

Getting more into the details

AncestryDNA has a unique collection of DNA samples from individuals all across Africa.  By looking at their genetic data, we can cluster certain individuals based on genetic similarity.  The points in the graph below (on the left) are colored by the part of West Africa in which the samples were collected (see the map to the right to coordinate colors with locations).

Interestingly, people group by color, which means that their genetic data tends to group by geographic region.  This shows that we can use an individual’s DNA to say something about where in the world their ancestors came from.

populations of africa
The graph above depicts the distinct genetic clusters of individuals from West Africa. Each point is an individual with deep ancestry in West Africa from our proprietary sample database. The color of each point corresponds to the country/region (shown in the map on the right) where a majority of that individual’s ancestors lived. The x and y axes indicate two primary axes of genetic differentiation (called principal components, or PCs) as inferred from sample DNA. Points closer together on the plot are more similar genetically.

AncestryDNA’s six new ethnicity regions of West Africa include Senegal, Mali, Ivory Coast/Ghana, Benin/Togo, Nigeria, and Cameroon/Congo.  The division of West Africa into these groups marks the first time that West African genetic ethnicity estimates have achieved this level of detail – bringing AncestryDNA’s total number of reported genetic ethnicity regions in Africa to nine.

AncestryDNA’s West African ethnicity update can help to link African American individuals to specific locations in West Africa. In the future, more detailed analyses of genetic data and family trees have the potential to reveal other important historical stories.

Thanks to the science team’s findings of genetic structure in West Africa, the new African ethnicity regions will provide a breakthrough for many African Americans, and may even help to reunite members of disrupted families.

Mary is hoping that this will be the case for her family.  “I better do this before I die, because if I don’t, who knows if anyone else will.”


Anna Swayne

Anna Swayne has 9 years of experience in the DNA genealogy world. At Ancestry, she leads efforts in developing education to help our community maximize their experience with AncestryDNA. She believes there is real power behind DNA and the story it can unlock for each of us. When she is not talking DNA you can find her hiking or cycling in the mountains or cooking at home.

1 Comment

  1. Paula Tillman

    I have considered doing a DNA test on my husband. His biological father is from Nigeria (we don’t know much else about him) and his mother is African American with some English and Native American. It would be interesting to see what else would come up. My son is a wonderful mix of both of us! (I am French, Irish, Italian, English).

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