Geneticist says we are all cousins under the skin

By Victoria Hansenvhansen@abcnews4.com

Charleston, S.C. (WCIV) -- If you've ever tried to trace your family history, chances are you didn't get very far, maybe a couple hundred years.{}

But what if you could learn more about your ancestors from thousands and thousands of years ago?{} According to one National Geographic explorer, you can. He says you already have what you need-- your DNA.

"Genetics can kind of take up where the written record leaves off," said Spencer Wells.

He's a population geneticist for National Geographic. Simply put, he studies the human race through DNA.

"DNA is a very long molecule. Believe it or not, if you took the DNA of just one cell in your body and you stretched it end to end it's a linear molecule," he said.{} "It would be about six feet long, one tiny microscopic cell and it's all packed into that cell."

Wells says copying that cell over and over again through generations is what makes us who we are. But, he says it's complex and tedious, with plenty of room for mistakes.{}

He likens it to copying a really, really long book in a short amount of time.{}

"So you're going back and checking and double checking but occasionally you're gonna make a typo. That happens at the DNA level too," he said. "It happens randomly at a low but measurable rate and that's what we call a mutation."

It's those mistakes, or mutations Wells looks for in tracing our ancestors thousands of years ago.

"Those become markers of descent over time," Wells said. "If you share one of these changes in your DNA with another person, means you share an ancestor the person who first had that chance in their DNA and passed it on to the two of you."

Wells says he's been able to use those markers of time to trace our human family tree back 60,000 years -- to Africa.

"So really what genetics is revealing is how closely related we all are.{} And then the actual journeys that we took as we started to leave Africa."

To track those journeys, Wells{}collects hundreds of thousands of DNA samples from people around the world.{} With the simple swab inside the cheek, he says he can tell when your ancestors left Africa and where they went.

"Often the reasons people were moving are the same reasons they might be forced to move today," he said.{}

Food, water, climate change all had an impact.

Wells spoke before a packed auditorium at MUSC Wednesday as part of their global health conference. One man in the audience had this reaction, "It gave us a lot of things to think about, not only our past, but mostly even how we will go forward in the future."

Wells says that's the point. Will climate change force us to move even more? He believes yes.{}

Are we really that different after all?

"We're really all cousins under the skin," Wells said. "We may think of people as being so different from ourselves, but in fact we aren't."