Soil Secrets | Explorers in the Field

(Rhythmic music) (Train horn) - I feel like that saying, if they say, you can make it in New York, you can make it anywhere. I am from Brooklyn, so I feel like I can do anything. My name is Carter Clinton, and I'm a genetic anthropologist and a National Geographic Explorer.

Presently, one of the major issues that we find in genomic research is the lack of representation for African Americans. Genomic research is the study of all of your genes at a basic level. And one of the major goals of this project was to contribute information from a historic, African American population. Soil has a lot of secrets that you can't see with the naked eye.

I'm studying 400-year-old grave soil to learn more about the health and lifestyles of a historic African American population. (Footsteps) (Oriental music) So this is the New York African Burial Ground. It's now a national monument. (Oriental music) In 1991, a construction crew attempted to erect a federal building at 290 Broadway.

Being one of the taller buildings in the area, it was about 30 stories high, they had to dig 30 feet below. And around 25 feet, they began to uncover and unearth human remains. After they found the human remains, they went back to the historical maps, and they realized that they had just rediscovered the New York African Burial Ground.

419 were excavated, and that's out of an estimated 15,000 individuals, over 6.6 acres of land. So here we have the New York African Burial Ground Grave Soil Collection, housed at Howard University. And each of the samples represents an individual who was buried 400 years ago, and each sample is collected from a specific body region from each of those individuals.

So we each have our own unique bacterial community, or signature, if you will, of bacteria that live within us, on us, like on our skin and our gut. When we die, that bacteria is the leading force in how our bodies are decomposed.

So what we're looking at is what survives after 400 years after a person has been buried. So we took the original soil samples, we sieved it, we collected those fine particles, and then we attempted a DNA extraction. So we did that hundreds of times over the span of about six months.

And then one day, we actually got results. It was the best day ever; it was the best day ever. So, even hundreds of years after a person passes away, you can see infectious disease bacteria that may be the result of what that person died from. (Running water) (Piano playing)

I feel proud. I feel proud to be an African American working on what could possibly be my direct ancestors. Being an African American and native New Yorker at the same time. It's so much more than just the tangible.

It's the knowledge that you had ancestors who lived years ago that contributed to this greater picture that you're now a part of. So we're not just contributing to science; we're contributing to history.