Posted by Julie Granka on September 12, 2013 in DNA, Science

The AncestryDNA science team presented the results of their latest research today at the Smithsonian Institute’s symposium on The African Diaspora in Washington D.C. Using unique proprietary DNA samples and a variety of statistical approaches, our science team has been able to separate West Africa into six separate population groups based on genetic data.  This advancement will provide a finer-resolution genetic ethnicity estimate for individuals with West African ancestry.

West African ethnicity

AncestryDNA’s six new ethnicity regions of West Africa include Senegal, Mali, Ivory Coast/Ghana, Benin/Togo, Nigeria, and Cameroon/Congo, each of which has a distinct set of tribal affiliations.  The division of West Africa into these groups marks the first time that West African genetic ethnicity estimates can achieve this level of detail, bringing AncestryDNA’s total number of reported genetic ethnicity regions in Africa to ten.

The announcement of the new genetic ethnicity regions were presented at The African Diaspora event earlier today by Dr. Jake Byrnes, population genomics senior analyst on the AncestryDNA science team.  Although these new ethnicity updates will not be made available to all AncestryDNA users for a few more months, we wanted to give the inside scoop on Jake’s Smithsonian presentation detailing the West African ethnicity update as well as additional research findings on the genetics of African Americans.

It can be extremely difficult to research one’s African ancestry using historical records alone, as most African American individuals in the U.S. are unable to find detailed records of their ancestors before the 1870s. Our AncestryDNA test can help family historians use genetics to pick up where the paper trail ends.

AncestryDNA leverages a unique proprietary collection of DNA samples from individuals with well-documented family trees to conduct innovative research in population genetics, human evolution, and migration. The science behind AncestryDNA is continually evolving and improving. During this ongoing process, the science team demonstrated that genetic data reliably shows population structure in Western Africa.  What this means is that the DNA of individuals from Western Africa clusters into a number of distinct groups. As a result, AncestryDNA can now more finely define genetic ethnicity regions in Western Africa. (See the visual representations below.)

 Caption: The graph on the left 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 (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. Comparison of the graph on the left and the map on the right reveals the similarity of the genetic and geographic structure.

Caption: The graph on the left 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 (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. Comparison of the graph on the left and the map on the right reveals the similarity of the genetic and geographic structure.

Population structure such as this is not new, and even exists in the U.S today.  Here’s an example from the 2010 census data.  Each point is an individual, colored by their self-reported ethnicity.

West African ethnicity 3

You’ll notice that people of similar backgrounds tend to stay and live in the same general geographic areas.  Imagine now if we could roll this map back in time to see where an individual’s ancestors immigrated to the U.S.!

The AncestryDNA science team is looking toward a future where we could reveal, in the absence of a family tree, the most probable locations where one’s ancestors lived – both in the U.S. and abroad.  To do this, the science team hopes to harness the power of collectively analyzing family trees of individuals with similar genetic profiles.

Though this project is still in its infancy, the science team has made some progress. First, we looked at the birth locations of individuals in the trees of all African Americans. Then, we looked for locations where, relative to all African Americans, there appeared to be an over-representation of birth locations in trees of individuals with a particular West African ancestry.  For individuals with Senegalese genetic ethnicity, we found what seems to be an over-representation of birth locations in South Carolina and Georgia in the 1700’s and 1800’s.

This might be an example where the genetics matches up with history.  In the 18th century, plantation owners in South Carolina and Georgia knew little about rice cultivation and preferred to import slaves from Sierra Leone, Gambia, and Senegal (the Windward Coast), where rice is a commonly grown crop. It is thought by some scholars that the Gullah people, who today live in coastal Georgia and South Carolina, descend from slaves imported from the Windward Coast to work specifically on rice plantations.

Providing more detailed ethnicity estimates for West African populations is crucial for American family historians.  Approximately 85-90% of today’s African Americans are descendants of enslaved Africans brought to America between 150 and 450 years ago – leaving many African Americans without a known family history prior to this time. AncestryDNA’s new West African ethnicity update will 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 important historical stories.

West African ethnicity 4

Thanks to the science team’s findings of genetic structure in West Africa, the new African ethnicity regions will be a breakthrough for many African Americans and may even reunite the origins of disrupted families.  But more is to come, as we are only scratching the surface of what is possible.

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.

37 Comments

    • Julie Granka

      Within the coming months AncestryDNA customers will start to see the fruits of our research incorporated into their ethnicity results.

    • Julie Granka

      Thank you for your interest! This advance in our genetic ethnicity estimates only relates to autosomal DNA — not to Y or mitochondrial DNA.

    • Julie Granka

      It will. All AncestryDNA customers will receive their new ethnicity results with these updates without having to take the test again.

  1. anthony parker

    I’ve asked Ancestry.com if they will have a raw data upload like Familytreedna has where you can upload raw data from 23andme to them,and they said there are no plans right now. That makes me upset,I would love to have my maternal grandparents 23andme looked at by Ancestrydna since they are the only ones with this new west African breakdown. I promised my grandparents when they did 23andme that they wouldn’t do any more tests (and spitting,even with an assistant collection kit,was rough for them).

  2. LaKisha David

    Wow. I just want to say THANK YOU! …and keep up the good work. Seriously, please keep it up. There’s some real healing going on from your work. Thank you.

  3. I had my test done through another company and it narrowed it down to Mozambique. It looks like your test doesn’t cover that area. Are there plans to expand to that other area where Africans were taken and enslaved in the Americas?

  4. Wanda

    Hi Julia,
    I have received my results from my DNA test, and I have a question regarding the findings. I was excited to know that West Africa especially the Ivory Coast was where the highest concentration of my genetics found. The other region in West Asia was a bit of a surprise but not entirely, because I have always felt a kindred spirit with the culture of Turkish people. I like the style of clothing, music, etc. I also have some European genes, which was not a surprise. What I would like to know is how did the emigration occur? I live in the Texas in the U.S. thank you for all of the research that you are doing, it really helps in knowing where one is from.
    Thanks again,
    Wanda

    • Julie Granka

      Hi Wanda, thanks again for your interest! I’d suggest looking through the detailed region descriptions on your results pages, as they main help to reveal some interesting history about your possible ancestors from that region.

  5. James

    I also had a significant amount of ethnicity correlated with Ghana. Are the results dealing with Ghana/ Ivory Coast related mainly to Akan tribes/peoples? Would it be possible to tell the self proclaimed ethnicity of the Individuals tested?

  6. Francesca Abbey

    My great grandmother Lila told me the story of our heritage so many times that it stayed on my mind all these years. What she also told me was that her African mother was a princess in Dahomey. So I had to find out who was king in Dahomey at the time her mother was a little girl. She had to be the daughter of either Ahosu Ghezo, (king is Ahosu in the Fon language) who was king of Dahomey from 1818 to 1858 or Ahosu Glele, who was king of Dahomey from 1858 to 1889. I’m figuring the young girl might have been born around 1856, give or take a few years.

  7. Eva S.

    Very interesting article. Will you be able to do more detailed work for Native Americans, too, sometime in the future? I have a relative that has been told that he has Native American in his blood, but your estimation will be too general to really pinpoint whether it is North American or South America. It seems there should be a way to be more specific in regard to Native American heritage, and I hope you will some day consider this as your next project. 🙂

  8. Sonia

    This is a great tool for those who are at a loss as to where to turn next. Do you have plans to do more research for slaves who were sent to the Caribbean?

  9. Karim

    This is excellent. What Ancestry’s science team is striving to do here is exactly what I’m trying to accomplish with my overall family history research. I look forward to the next phase of updates regarding this pertinent project.

  10. monica

    I was surprised and fascinated to learn that I have trace ancestry from Senegal and 6% Native American. Given all this amazing work on African ancestries, I am wondering why there is so little detail about Native American ancestry? I’m hoping that a breakdown of the North and South American continents will soon be possible too. Thanks.

  11. Julie

    I just found out my Father is <1% Mali. This is all new to me. I am excited but wondering many generations this would go back?

  12. Kenyan Summers

    I am so excited about seeing my roots. My DNA result was so worth the price and the wait (which was about 2 weeks).

  13. Jess

    Howdy, I am white. Have white parents and grandparents, etc… My DNA ethnicity revealed 1% Senegalese. My grandmother is from South Carolina and mentioned a couple times having “negro” in her family history. What is the chance that this Senegalese is accurate? Or not accurate?

  14. Beth W

    I am a White presenting person with only knowledge of northern european ancestry. So far, out of 6 relatives on my mother’s side, I am the only one who has had 12% Iberian Peninsula and 2% Mali DNA results, the rest european. What does this mean? How can I begin to trace what side of my family our ancestors with African DNA came from?

  15. mahamat

    all of this is not real you people are trying to divide us with your fake history and genetics you don’t know african people because you aren’t african

  16. Government should be left responsible for the funding of this project, especially since they also funded off of the oppression of our Ancestors, & haven’t been held accountable for their hand in the confusion of our people.

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