Geneticist Rick Kittles and Gina Page helping families put together missing pieces of their heritage through African Ancestry.

The UN designated the International Decade for People of African Descent, from 2015 to 2024, to promote the recognition, justice, and development of African descendants worldwide. Through various programs, events, and awareness campaigns, the Decade seeks to create a platform for dialogue, understanding, and positive change in the lives of people in the diaspora. Africa Renewal is highlighting the journeys African Americans are taking to reconnect with Africa - the continent their ancestors called home. This is the last piece in the four-part series:

In 1999, the pioneering geneticist Rick Kittles joined a team of historians, archaeologists and biological anthropologists to examine remains in New York City's Financial District.

Some scientists and experts suggested that the remains may be those of Native Americans or Europeans, Dr. Kittles said. "My role was to isolate DNA [deoxyribonucleic acid] from the bones and develop a way to figure out if they were of African descent."

They were.

Today, that landmark near Wall Street is the African Burial Ground National Monument. It is considered one of the most important archeological finds of the 20th century," according to the US National Park Service, which estimated that 15,000 free and enslaved Africans were interred there.

Dr. Kittles, who received his PhD in biological sciences from George Washington University in Washington DC, spent five years on the interdisciplinary project.

A reporter once asked him, "If you can do that for the bones, why can't you do that for regular people?" in reference to DNA tracing.

So, he drew from his research in anthropology, evolutionary biology and human genetics and applied it to the field of ancestry.

In 2003, Dr. Kittles partnered with Dr. Gina Paige to launch African Ancestry Inc., a genetic tracing company that boasts the largest database of African lineages dating back 500 to 2,000 years. Unlike other genetic and genealogy firms, African Ancestry does not provide percentages of one's lineage rather it pinpoints to a present-day African country or ethnic group of origin by tracing one's maternal or paternal line.

A mixture of lineages

According to a study in the American Journal of Human Genetics, the average African American carries 24 percent European ancestry. For test-takers, it can be a painful reminder of how the legacy of slavery still robs African Americans of their identities.

Unlike other genetic and genealogy firms, African Ancestry does not provide percentages of one's lineage. Instead, the company pinpoints a specific present-day African country and ethnic group of origin by tracing one's maternal or paternal line.

LaKisha David has been conducting academic genealogical research while she was a graduate student at the Massachusetts Institute of Technology and as a PhD student and assistant professor at the University of Illinois at Urbana-Champaign. During that time, Ms. David has also dedicated time to personal genealogical research.

"I already had a psychological connection to Africa, so I wanted to get more details," said Ms. David.

Early in her research, she received her family's DNA results from African Ancestry revealing that she hailed from the Tikar, Hausa, and Fulani people of Cameroon.

"The African Ancestry results helped me to narrow down my search to a specific area," said Ms. David, who appreciated the ancient discovery. "It made me more eager to learn about the area, the history and the nuances."

Now that she knew her roots, Ms. David wanted to explore more recent branches of her tree, particularly the period before her ancestors were enslaved. "The narrative was that the period of separation was too long ago to find living African relatives," said Ms. David.

Then she submitted DNA to other genetic testing sites including 23 and Me, which is where she found a cousin from Cameroon. "We shared an ancestor within the last 500 years," said Ms. David. "Now I have a family history, even though it's not complete. "I have an even greater connection and a psychological claim to Cameroon."

When Dr. Kittles tested his own DNA, he expected to find a mixture of lineages because enslavers were constantly separating and selling enslaved Africans to different colonies or states in America.

On his mother's side, he found Ibo and Hausa from Nigeria; on his father's side, he found Mandinka and European. "I was shocked to see the results in the lab," he said of his European ancestry. He reconciled his scientific revelation by remembering family stories of a white ancestor and understanding the legacy of slavery.

That legacy involved generations of European captors raping and breeding enslaved African women and girls like cattle.

Harriet Jacobs recounted the horror in her 1861 autobiography, Incidents in the Life of a Slave Girl. More than 2,300 other survivors shared their testimonies in the collection, Born in Slavery: Slave Narratives from the Federal Writers' Project, 1936-1938.

"Those men passed their European ancestry to their African male children," the company stated in a blog post. It cautions its African American clients, particularly men who take what it calls the PatriClan Test to trace their paternal DNA, that their results have only a 65 percent chance of yielding an ancestor from Africa.

However, both genders can trace their maternal lineage with the company's MatriClan Test, which has a 92 percent chance of yielding an African ancestor.

Philadelphia-based genealogist Dena M. Chasten fell into that small percentage of test-takers whose results failed to yield an African maternal ancestor.

"When I tested my DNA on my maternal line, I was expecting to find my African lineage. Then when the results came back European, I said, ' What is that!"'

Ms. Chasten's confusion motivated her to dig deeper by working with additional genetic testing firms, following a paper trail and making phone calls. Eventually, her search resulted in locating a distant cousin in Ghana. (You can read about her journey here).

Act of resistance

Test results help to heal the trauma of the transatlantic slave trade and welcome African Americans home, Dr. Paige explained. "Black people should take the test as an act of resistance, because [our ancestry] was something we were never supposed to know."

Denying them knowledge of their origins was an intentional strategy to keep African Americans disconnected from their power and their roots, Dr. Paige said. "When you are unrooted, you have no foundation. You are at the mercy of whatever happens around you."

Dr. Kittles grew up feeling that disconnection. "I wanted us to see ourselves in African people and the culture," he said. He believed that, if African Americans knew their origins, then they would be more inclined to tackle the challenges and help alleviate hardships facing those nations.

With this information, people can operate differently, Dr. Paige said. "We have the ability to live more purposefully because we have strengthened our identities."

Ironically, when her DNA test revealed that she was Hausa from Nigeria, she was not particularly moved: she found pride in knowing that she was simply a descendant of Africa.

Besides, Dr. Paige had her hands full at the time. "I was in the midst of launching a start-up," said the Stanford-educated entrepreneur. "I was focusing on making sure the business was going to be sustainable."

Ancestral imperative

Twenty years later, African Ancestry has helped more than one million descendants of slaves unravel the mysteries of their heritage.

The company works with Diallo Sumbry, Ghana Tourism Authority's first American ambassador, as its director of partnerships. A Fulani descendant, Mr. Sumbry was instrumental in arranging for African Ancestry to share DNA results on the site of the former slave dungeons in Cape Coast, Ghana, during the Year of Return.

In addition to Ghana, the company hosts African American family reunion tours in Cameroon, Gabon, Senegal, and Sierra Leone. During the tours, it presents test-takers with their ancestry reveals.

While doing the ancestry reveals, Dr. Paige has discovered what she refers to as an "ancestral imperative" when she described a scene that happened like clockwork.

"At the Door of No Return, about five minutes before every single ceremony, I'd start crying uncontrollably out of nowhere," she said. "I didn't know why I would start crying. I would have to wait for the tears to stop."

One day, a spiritual leader at the ceremony told her, "'You are giving birth. You are giving someone a new perspective on their life."'

Now she lets the tears flow, with no apologies.

"It's very clear to me that I'm doing this work because the ancestors want this work done," Dr. Paige said. "The ancestors want us to know who they are."

Ms. Beard is a writer and educator based in New York.