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Feature Story: The African Diaspora

Researcher draws human pedigree on window

The African Diaspora: Integrating Culture, Genomics, and History

Identity, Health, and Personal Ancestry Come Together

by Jacquelyn K. Beals

“The genetic techniques have to be combined with anthropological knowledge, with historical knowledge and, ultimately, the people who we’re discussing have a say in their identity. … Identity is more than just the science, it’s also the culture.”   

                                            – Fatimah Jackson, UNC Chapel Hill

The Smithsonian and the National Human Genome Research Institute in September 2013 co-hosted a symposium on the African Diaspora: Integrating Culture, Genomics, and History (view video), in conjunction with the “Genome Unlocking Life’s Code” exhibition.  “The Symposium explored how historical and genomic information is used to understand identity, health, culture and personal ancestry," stated Vence Bonham, chair of the planning committee.

With advances in technology, a younger group of genealogists now searches for their personal history and identity using genomic analyses and Internet search engines.  Symposium speaker Dr. Alondra Nelson showed a typical group of genealogists when her research started a decade ago. “It tended to be a pursuit of older folks, older African-Americans,” said Dr. Nelson. Today she’s “trying to make connections with younger genealogists, and you find a lot of these on YouTube.” For younger African-Americans, genealogy is less about archival research and more about cutting-edge DNA ancestry testing and its results. 

Dr. Nelson speaking at podiumDr. Nelson’s shared the story of a young Black woman who’d just received her genetic ancestry test results and called her grandmother to share the results. “Grandma,” she said excitedly, “we’re from Cameroon!” After a pause her grandma replied: “No, we’re from South Carolina.”

And therein lies the big question – where is anyone from, really? And another compelling question – what can our origins tell us about ourselves? People used to answer these questions by following paper trails. Has DNA testing made genealogy simpler or more complex?  It depends who you ask.

Where are we from, really?

Mary Jo Arnoldi, curator of Africa Voices and chair of the museum’s Department of Anthropology stated,  “that our human species evolved in Africa and we all share the same ancestry at this most profound level.”

“Our human species evolved in Africa and we all share the same ancestry at this most profound level.” 

But African-Americans want to search for ancestors who crossed the oceans – willingly or unwillingly – in the last 500 years.

Testing companies are using that scientific innovation and research to enrich African Americans’ search for their cultural and genetic roots by identifying more specific geographic locations and ethnic groups. With larger and better-researched reference populations, geographical localization will improve. But even the best estimates are based on statistical probability. One respected company requires 70% confidence to report a given result – a reasonable standard, but that 30% leaves a lot of wiggle room!

Types of DNA testing: What can they tell you?

Wall of ACGT charactersMost testing companies analyze three types of DNA:  mitochondrial (mtDNA), Y chromosomes, and autosomal DNA. A woman’s egg passes mtDNA to her children, whether boys or girls, but a sperm’s few mitochondria don’t persist after fertilization. All of your mitochondria contain your mother’s mtDNA, and all her mitochondria contain her mother’s mtDNA, so only one of your eight great-grandparents (your mother’s mother’s mother) contributed your mtDNA. The other seven are not represented, and this ratio gets progressively tinier the further back you go. 

The Y chromosome passes from father to son and genetically defines a human male. Only males can transmit a Y chromosome, and only males inherit them. A man’s Y chromosome can be traced to his father’s, father’s, father’s, father – and farther. But, as with mtDNA, this represents only one man in each generation – one out of 16 great-great-grandparents.

Autosomes are the 22 chromosome pairs that aren’t X or Y. Half come from your mother, half from your father – each parent contributes one of each pair. But during egg or sperm formation, chromosomes are mixed and matched, dealing out randomly assorted chromosomes from each grandparent – and here genetic genealogy gets really fascinating! Scientists are starting to pinpoint small sections of each chromosome, finding their probable origins in African, Asian, European, Jewish, or Native American gene pools.  

What do our origins tell us about ourselves?

DNA evidence can also carry meanings that reach beyond historical records.  A husband-wife team of intermedia artists – Dr. Mendi and Keith Obadike – described their “American Cypher Project,” which examines American stories about race and DNA. Starting with the relationship of Thomas Jefferson and Sally Hemmings, they asked: How has DNA evidence changed the way people talk about that story? How does it raise different questions? What do people think DNA does? Family History DocumentsPaper trails, old photos, and family stories contain inconsistencies and gaps. But people tend to expect precision and infallibility from DNA science.

And yet: “We were really sort of inspired by how ambiguous some of the science was, or how inconclusive it was,” Keith said. “As artists we thrive on ambiguity. It’s like when all the answers aren’t there, so we can really generate some … We don’t know how you feel about it as scientists, but for us, it’s a goldmine.”

Speaker, Dr. Sandra Soo-Jin Lee picked up these ambiguities in her survey research, which asked the question: “An individual who identifies as African-American receives genetic ancestry test results that indicate that she has 0% African ancestry, 87% European and 13% Asian ancestry. I would classify her as _______.”  16% of respondents chose: “What she said is what she is, African-American”; 2% picked Asian-American, 18% said European-American, and 41% said “other”; the remaining 23% “don’t know.” 

The survey allowed respondents to explain their choice of “other.” Write-ins included:  lab mix-up; mixed race, but it’s not up to me to decide; African-American is a cultural identity, not about a “racial blood quantum”; I’d call her Eurasian; and, I’d need to know why the classification: social and cultural might be African-American, but to tailor drugs/treatments for medical purposes, then European/Asian would be most important.

 “Has DNA testing made genealogy simpler or more complex?” It does depend who you ask. 

So we ask again, “Has DNA testing made genealogy simpler or more complex?” It does depend who you ask. But more and more people are asking, and the answers extend far beyond the sequence of bases in DNA, encountering issues of culture, history, and personal identity.  

“Over the past several years, the National Museum of African American History and Culture has produced a very ambitious series of engaging programs with a primary focus on historical events or figures and the vibrancy of  African American culture and art,” said Dierdre Cross, program coordinator at the NMAAHC. But “the African Diaspora Symposium … added another dimension to our programming:  to have our audience participate in discussions focused on scientific innovation, as represented by genomic research, and its direct impact on African American health issues and community history.”

* held September 12, 2013, at the Smithsonian National Museum of Natural History, Washington, DC

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