finding your roots

Haplogroups: Tracing Deep Roots with DNA

Genealogy Team May 15, 2012

At one point in the PBS series Finding Your Roots, Harvard genetics professor and founder of the Personal Genome Project George Church is asked about the difference between written genealogical records and DNA.

“Written records go back to the dawn of written history,” Church said. “DNA goes back to the dawn of human existence.”

This is the power of genetics — it can tell us not just about ourselves, but also about human history and our place in it.

We can map the story of human migration out of Africa not just from archaeological evidence — the bones and artifacts our ancient ancestors left behind — but also using the DNA we inherit only from our mothers or only from our fathers.

These bits of DNA — the Y chromosome (y-DNA) passed from father to son, or mitochondrial-DNA (mtDNA) passed from mother to child — are inherited almost identically in each new generation. The key word here is “almost.”

Over thousands of years there are occasionally small changes in the mtDNA and the y-DNA that become a kind of timestamp for a person’s deep ancestry. Because geneticists can calculate the rate of those changes over time, the changes act as markers in time that conveniently match up with points in the history of human migration.

As people migrated, groups of people also became more isolated from one another. The small changes concentrated over generations within these isolated populations set the stage for the pattern of genetic diversity we see today. Specific y-DNA sequences and specific mt-DNA sequences are associated with certain groups that were culturally or geographically more isolated, passing certain mutations from one generation to the next until they were prevalent.

People with similar geographic ancestry share these small differences in their mtDNA or their y-DNA and they are grouped together in what are called haplogroups— specific clans or branches of the human family tree. There are hundreds of different haplogroups on both the maternal and paternal sides. Some of them can indicate things like whether you have ancestry in a Nordic country or the Middle East

In a family tree, the maternal line (like mitochondrial DNA) traces back through a string of mothers; the paternal line (like the Y chromosome) traces back through a string of fathers.

This doesn’t mean that if you (or your father if you are a woman) have the same paternal haplogroup as Thomas Jefferson (T), or Genghis Khan (C3), or Bono (V) or Albert Einstein (E1b1b1*), that you are “related” to them, at least not in a strict sense. It does mean that you have a common ancestor dating back thousands of years. You could find that common ancestor if you followed your father’s, father’s, father’s line back each generation and the other person did the same. Eventually those two paternal lines would meet with a shared ancestor.

By finding out his haplogroup, Prof. Gates now knows that he is likely to have Irish ancestry on his paternal side. He, and a majority of men in Ireland, share the paternal haplogroup, R1b1b2a1a2f2. It is thought to come from an Irish King named Niall of the Nine Hostages. Prof. Gates is one of the very few African Americans, about 1 percent, who traces his ancestry on both his maternal and paternal side to Europe.

By tracking their maternal DNA, Prof. Gates was able to inform the actresses Kyra Sedgwick and Maggie Gyllenhaal not just of their Jewish ancestry, which isn’t so surprising, but in Gyllenhaal’s case that her Jewish ancestry traces back to one of four Jewish founding mothers who lived thousands of years ago. In the case of Brown University President Ruth Simmons, Prof. Gates was able to look at her maternal line and see that she has Native American ancestry. (Women do not get y-DNA from their fathers, but their paternal ancestry can be traced by testing a close male relative.)

With the help of geneticist Rick Kittles, Prof. Gates was able to help his guests track their ancestry to regions of Africa. He did this by comparing the guest’s mt-DNA with databases of people from certain locations in Africa. This is how Prof. Gates was able to tell former Secretary of State Condoleezza Rice that her maternal DNA shows she has ancestry in what is now modern day Cameroon and Samuel Jackson that his y-DNA indicates he has ancestry from what is now modern day Gabon.

This map shows the origins of the maternal line of Finding Your Roots guest Sanjay Gupta. This genetic lineage, U2c, is found primarily in South Asia. Darker colors show where this lineage is most common.

Although this information doesn’t always tell the guests much about close relatives, it gives them a connection to their deep ancestral roots in a way that resonates. Gates took his guests comedian Margaret Cho, entrepreneur Martha Stewart and CNN medical correspondent Sanjay Gupta on a similar journey tracing back deep ancestry by looking at their maternal haplogroups. Cho’s D5a haplogroup is rare among Koreans, and indicated ancestry in China, while Stewart’s maternal haplogroup W6 connects her eastern European roots to the Tatars people of the near east. In the case of Gupta, his maternal haplogroup U2c only confirmed his deep roots in India going back thousands of years.

In each case, the guests said the information not only helped them complete the picture of their families, but also the picture of themselves.

About the Authors:
Joanna Mountain is a geneticist who is a consultant to the PBS series “Finding Your Roots,” and consulted previously on the PBS series “Faces of America.” Dr. Mountain completed her PhD in Genetics at Stanford University and has spent over 20 years studying human genetic diversity. Currently, she is Senior Director of Research at 23andMe, Inc.

Scott Hadly is a writer with extensive experience as an investigative reporter. Currently Mr. Hadly is Content Editor at 23andMe, Inc.



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  • Louise Halsell

    May 16, 2012 at 12:24 am

    This is a most exciting educational
    experience. Thank you for explaining
    this very complicated material so
    beautifully and simply.

    It leaves me breathless!

  • garth tuttle

    May 19, 2012 at 1:55 pm

    just this: looking at the map, I see that many of dr. Gupta’s ancestors came from areas where people from the Elamite/ Tamil -Dravidian cultures (and languages ) are common; some also outline the coastal areas in South Asia where the Chola Empire had suzreinity; in the area of south -eastern arab peninsula, they seem to be located also in Muscat and near the coast of Barain – which was thougt by at least one archeologist to be the location of the legendary state of dilmum (sp?) – which traded as far away as South Asia

  • Louise Cates Jones

    May 23, 2012 at 8:23 pm

    Enjoyed all of Mr. Lewis’ programs – wish I had time and knowledge as to how I might trace my ancestry. I find all of this very, very interesting.

  • Debra Cramer

    May 24, 2012 at 2:45 pm

    There is a community in New Jersey called Timbuctoo. As reported in the Washington Post, “Timbuctoo was founded by freed blacks and escaped slaves in the 1820s. It was probably named after Timbuktu, the town in Mali near the Niger River, although researchers are still trying to find out how and why it got its name. The neighborhood still exists in the township of Westampton, N.J., about a 45-minute drive northeast of Philadelphia, an enclave of many acres, so tiny and tucked away that when you ask someone at the store two miles away, he tells you he has no idea where it is. ” Many descendants of the original occupants still live there. I think it would be great is you could help them to find out if they are descended from slaves who were brought from Tinbuktu in Mali.

  • Donna L. Ramirez

    May 29, 2012 at 10:03 pm

    My question relates somewhat to the haplogroup conversation in that with Linda Chavez you found her roots beyond the Americas. This is also our family. We have the very same Apodacas in our family tree, but our research stopped here in the Americas. Would we be able to access Linda Chavez’ family tree? My father, who has worked so hard on hid family tree would be most appreciative.

  • cindy rieth

    June 21, 2012 at 4:38 am

    My mother is 93 and always proud of having Native american indian in her geneology. my neice how has been tracing her geneology tells her no. her greatgrandmother was not indian as my mother had been told. i sent her DNA to I still can not tell her. it is so complicated. where did i go wrong and is there a web stie that i could send her dna that would just answer the question- does she have native american blood. i feel as if i would have to be a scientist to deceifer the info i rec’d from genebase.

  • July 7, 2012 at 1:02 am

    i must know because my mother & grandmother are into genealogy of your outer banks..

  • Catharine

    July 7, 2012 at 4:07 pm

    As a warning to people planning to do this. My sister bought the 23 and me kit for her husband as a father’s day gift and what she got back was NOTHING like what they show on the TV. In a multi page report there were only three lines that applied specifically to my brother-in-law and they were very generic in nature. It’s not worth the 300 dollars they are charging.

  • July 26, 2012 at 10:06 pm

    How and where do i begin tracing my roots? I was born in Jamaica in 1958 father last name is LaMont and mother’s maiden name is Fyfe sometimes spelt Fyffe. Can i provide my DNA if yes… is ther a kit or something i can purchase and or order/ Please advise


    Patrick LaMont


    August 18, 2012 at 1:57 am

    cindy rieth, DNA tests don’t tell everything. Y-DNA and mtDNA are a very small part of one’s genetic history. Your mother’s father and all his ancestors, and of your father’s mother and all her ancestors can’t be seen. Same with your maternal grandmother’s father and with your paternal grandfather’s mother. And so on, so forth.
    The Y-chromosome is passed from father to son unchanged. The mtDNA is passed on intact from mother to child. All people–men and women alike– inherit their mtDNA exclusively from their mothers.
    For example, there is a woman Rita her mother’s father is an asian but testing her DNA you can’t see that she is a quarter asian.

  • August 25, 2012 at 5:26 am

    I have a commment & a question 1st thank God for shows like this they inspired me to continue searching an unkown family in my
    mother side 2sd how can I contnue a search that involves the caribbean/Spain/France and decendants that are unwilling to help me on this search when I do not have a lot of info on my mother father and his family?is like a everyone does not want me to search ?help

  • November 9, 2012 at 1:19 am

    and so it has to start again and it’s not technically wrong

  • Pamela Harvey

    December 17, 2012 at 3:03 pm

    I took a genetictest from and they stated that they could not idenity 11% of my DNA related to any ethnic group. What does this mean?

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About the Series

The basic drive to discover who we are and where we come from is at the core of the new 10-part PBS series Finding Your Roots with Henry Louis Gates, Jr., the 12th series from Professor Gates, the Alphonse Fletcher University Professor at Harvard University and director of the W.E.B. Du Bois Institute for African and African American Research. Filmed on location across the United States, the series premieres nationally Sundays, March 25 – May 20 at 8 pm ET on PBS (check local listings).

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Posted by Genealogy Team, 15/5/2012
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Posted by Henry Louis Gates, Jr., 15/5/2012

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