DNA analysis traces African slaves back to their roots

Maxilla and mandible of one of the three 17th century skeletons from the Caribbean island of St. Martin showing a common type of African dental modification. PNAS/H. Schroeder et. al.

To better understand the complex history of slavery, it helps to know more about the origins of millions of individuals who were shipped from their homes in Africa to plantations in the Caribbean, South America and the United States.

Historians have a good idea that 12 million or so slaves came from West and West-Central Africa between 1500 and 1850. But incomplete and scarce historical records have made it difficult to offer crucial details about the slaves' ethnic origins and the regions from which they were taken.

Now, a team of researchers says they have for the first time used a new DNA technique to fill in these gaps, which could provide further insight into the slave trade.

14 Photos

Sixteen years after hundreds of remains were found, a national monument opens to the public

Writing in Proceedings of the National Academy of Sciences (PNAS) Monday, researchers led by Hannes Schroeder of the Centre for GeoGenetics at the University of Copenhagen described how they used whole genome capture to retrieve the DNA from 400-year-old skeletal remains of three slaves, known as the Zoutsteeg Three.

"There are historical records - merchant ledgers, shipping records and the like - but they tend to refer to coastal shipping points rather than the slaves' actual ethnic or geographic origins. This is where the DNA comes in," Schroeder said. "It can provide new insights where historical information is missing. In that way, DNA is simply another type of archive that we can use to study the past."

Schroeder and his team analyzed the DNA from teeth recovered from a construction site on the Caribbean island of Saint Martin back in 2010. They then used a different technique known as principal component analysis to compare that DNA with 11 modern West African reference populations. From that, they were able to conclude the individuals most likely came from Bantu-speaking groups in northern Cameroon and non-Bantu-speaking communities living in present-day Nigeria and Ghana.

When they were first uncovered, the remains of the three slaves were dated back to the 17th century by way of shards of pottery and other artifacts found at the site. It was also determined they were most likely slaves, given the time period and the fact their teeth had been filed, a common custom among Africans then.

More here:
DNA analysis traces African slaves back to their roots