Wednesday, October 11, 2017

Pinpointing the Origin of Family's Igbo Ancestry with DNA

Source: Wikipedia, public domain

DNA-testing multiple family members always prove to be extremely beneficial. About two years ago, I tested my mother’s first cousin with 23andMe. Cousin Armintha’s father and my mother’s father were brothers, so they share the same paternal grandparents, Bill & Sarah Reed of Tate County, Mississippi. Last week, while checking my cousin’s account for new matches, I saw a new DNA relative with an African name. This is always exciting! He shares 0.12% (9.0 cM) [2,240 SNPs] on chromosome 5 with Cousin Armintha. Luckily, his profile indicates that he was born to Nigerian parents of Igbo descent. To safeguard privacy, I will refer to him as Igbo Cousin 1. His posted surnames are Egolum and Anyiwo.

When I viewed the “Relatives in Common” section, I was pleasantly surprised. Igbo Cousin 1 also shares 9.0 cM of DNA [2,290 SNPs] with my mother and her brother, Uncle John. See Figure 1 below. He also matches Cousin Bryan, whose great-great-grandfather, Jerry Edwards, is strongly believed to be a brother to their great-grandfather, Prince Edwards, their Grandma Sarah Reed’s father. In the “Shared DNA” column, YES is noted for both my mother and Uncle John. According to 23andMe, “Shared DNA” means that an individual and their two genetic relatives share a portion of the same DNA segment. Therefore, since Igbo Cousin 1 is matching Cousin Armintha on a single chromosome 5 segment, my mother and Uncle John are also matching him on that same segment. NO is indicated for Cousin Bryan, so he is sharing DNA with Igbo Cousin 1, either on another chromosome or on a different section of chromosome 5.

FIGURE 1: Relatives in Common with Igbo Cousin 1

I also noticed that Igbo Cousin 1 shares 0.36% (27 cM) of DNA with another Nigerian-American who had been in our relative databases for over a year. I will refer to him as Igbo Cousin 2.  YES is also noted for “Shared DNA,” which means that he, Cousin Armintha, Igbo Cousin 1, my mother, and Uncle John all share the same chromosome 5 segment. Wow! They are considered a triangulation group. In other words, they all descend from a common African ancestor. Of course, I immediately clicked YES to view the segments on the chromosome browser. I reorganized the comparison list to compare Igbo Cousin 2 with Igbo Cousin 1, Cousin Armintha, Mom, Uncle John, and Cousin Bryan. See Figure 2 below. I was thrilled with what I saw!

FIGURE 2: Comparing Igbo Cousin 2 with Everyone

FIGURE 3: Comparing Cousin Armintha with Both Igbo Cousins,
Uncle John, and Mom on Chromosome 5

Turns out, Igbo Cousin 1 and Igbo Cousin 2 share 27 cM on two segments – 11.8 cM on chromosome 5 and 14.8 cM on chromosome 8. This is in the range of 3rd cousins-once removed to 4th cousins. Not only that, I discovered that while Cousin Armintha, my mother, and Uncle John share the same chromosome 5 segment with both Igbo cousins, Cousin Bryan shares identical DNA with both Igbo cousins on chromosome 8. This is indicating that the kinship to our Igbo cousins may be thru one of our Edwards ancestors. Everyone likely descend from a common Igbo ancestor. How could I confirm this?

Eager for confirmation, I went to for clues. GEDmatch is a free, third-party DNA utility site that enables people to find the family connection between others who have uploaded their autosomal DNA raw data files from either 23andMe, AncestryDNA, or FTDNA. Think of GEDmatch as “DNA Central” – the central location where autosomal DNA test takers can compare their DNA to others, utilizing their vital chromosome browsers and other neat tools. My goal was to see if there are any known family members who match my mother, Uncle John, and Cousin Armintha on chromosome 5. If so, that will enable me to determine if this chromosome 5 segment truly came from their grandmother, Sarah.

So I performed the “People who match both kits….” function in GEDmatch with Uncle John and Cousin Armintha’s kit numbers first, since they share the longest identical segment (129 cM) on chromosome 5. See the gold bar in Figure 3 above. I then viewed their mutual matches on the 2-D chromosome browser. Lo and behold, their 3rd cousin-once removed, Verena, matches both of them and my mother on chromosome 5, in what genetic genealogists call "overlapping segments." She shares a 7.0-7.3 cM segment [900+ SNPs] with them on chromosome 5. See Figure 4 below. Cousin Verena took the AncestryDNA test and had uploaded her raw data file to GEDmatch. This was a great discovery! Why? Because Cousin Verena is related thru Grandma Sarah. Her great-great-grandfather, Peter Edwards, and Grandma Sarah’s father, Prince Edwards, were brothers. There are no other known connections to Cousin Verena, after analyzing her family tree.

FIGURE 4: Comparing Cousin Verena, a descendant of Peter Edwards,
with Cousin Armintha, Uncle John, and Mom on Chromosome 5 in GEDmatch

FIGURE 5: Cousin Verena inherited the same DNA on chromosome 5
in the boxed section above.

Wonderfully, this confirmed that their chromosome 5 segment came from the Edwards side, thru one of their MRCA (Most Recent Common Ancestor), which would be the parents of Peter and Prince Edwards. In other words, Uncle John and Cousin Armintha, as well as my mother, inherited chunks of the same identical DNA on chromosome 5 from their great-grandfather, Prince Edwards. Since our Igbo cousins share 8 to 9 cM of identical DNA with them on chromosome 5, and since they share 9.0 cM [1,078 SNPs] of identical DNA with Cousin Bryan on chromosome 8, our Igbo cousins are related to the Edwards side of my mother’s family.

“Ogba Ogumba” – an Igbo Name

As I revealed in previous blog posts, oral history and genealogical clues revealed that the parents of Jerry, Prince, Peter, and others were likely Luke Edwards (born c. 1790) and Lucy Edwards (born c. 1795 in Georgia), who may have been known as “Reedia.” The late Cousin Dr. Sidney Edwards Sr., a great-grandson of Jerry, interviewed family elders in Mississippi around 1970. They relayed to him that Luke told their grandparents that he was captured in Africa and brought to Virginia. I uncovered that he had been enslaved by William Edwards of Panola County, Mississippi. Not only that, Luke communicated to his family that his African name was “Ogba(r) Ogumba,” which he was forced to renounce. Recently, several Nigerians of Igbo descent claimed the name as theirs without hesitation. Read more about this here.

Our Igbo cousins are related to my Edwards family, either thru Ogba Ogumba or via Lucy. But as you may imagine, my bets are on Grandpa Ogba Ogumba! And I’m not a gambler. Maybe the future will reveal more definitive evidence. Interestingly, the parents of both Igbo cousins are originally from Anambra State, in southeast Nigeria, the heart of Igboland. But check this out! A tourist attraction in Anambra State are the Ogbunike Caves, which are a collection of caves that are situated in a valley blanketed by tropical rain forests behind the "Ogba Hills." Africans shrouded in those caves from slave-raiding convoys during the period of the transatlantic slave trade.

Transatlantic slave trade voyages data show that nearly 40% of all documented human imports into Virginia and Maryland, the largest concentration of enslaved Africans, were taken from the Bight of Biafra region, also known as the Bight of Bonny. This region encompassed the coasts of present-day Nigeria, Cameroon, Equatorial Guinea, and northern Gabon. A majority of these captives were described as Igbos, who were embarked from the major trading ports at Bonny and Calabar, in present-day southeastern Nigeria. According to Douglas Chambers, the state of Virginia itself received nearly 37,000 enslaved Africans from Calabar in the early 19th century, and 30,000 of them were Igbos [1]. Consequently, most African Americans, who are descendants of enslaved Africans brought to America, have at least one Igbo ancestor. For more information, read Fonte Felipe’s very informative article, The Igbo Connection for Virginia & Virginia-Descendants.

[1] Chambers, Douglas B. (March 1, 2005). Murder at Montpelier: Igbo Africans in Virginia. University Press of Mississippi. p. 23.