A family tree for all mankind?

To all humans reading this — science confirms what Sister Sledge had been singing all along. We are family, and now there’s a family tree to prove it.

It’s not as simple as tracing lines between you and Grandma Edna all the way back to Noah and Adam. According to the study published in the Feb. 25 issue of the journal Science, the world’s largest unified human family tree was created by merging DNA samples from 3,601 modern people and eight ancient people and extrapolating estimated genetic variation, reproduction rates, and human migration patterns.

The idea of a genetic family tree isn’t new, but until recently no one had been able to piece together so many DNA samples into one coherent family picture. One reason is the size and location of the data.

Yan Wong, a researcher at the University of Oxford’s Big Data Institute and one of the primary authors of the study, said the full genomes of the 3,609 people take up about 6 terabytes of data and were spread across eight databases. Using modern technology, Wong and the rest of the research team developed ways to combine, convert, and compress this data into a manageable workload. Even so, processing the data still required about a week using a powerful computer cluster at their research facility.

Wong argues that this family tree, and the study of modern genetics in general, does not support the idea that humans were descended from two humans. In other words, scientists think Adam and Eve had company, and they most likely did not look like modern humans.

However, "we don’t have a preconceived idea of human history,” and Wong hoped the data would “speak for itself.”

A digital visualization of the family tree shows man appearing on the global scene in northeast Africa hundreds of thousands of years ago. Wong said the study doesn’t imply a particular start date for humankind. “I don’t think that our study says anything about when humans ‘came to be,’ other than confirming that it was a gradual and complex process,” he said.

Ann Gauger, a senior fellow at the Seattle-based Discovery Institute who holds to a creationist view of man, isn’t troubled by the study. She pointed to the family tree’s assumption of interbreeding between Neanderthals and Denisovans — ancient human species Gauger likens to “cousins of Adam and Eve.” Gauger said the fact that the family tree has them showing up around 500,000 years ago lines up with her own calculations of placing Adam and Eve at the start of mankind.

“It might strike you as crazy to have a 500,000-year-old Adam and Eve, but I’m fine with it,” she said.

Other scientists took more serious issue with the study’s findings. Robert Carter, a scientist and speaker for Creation Ministries International, said the study wrongly assumed that the location a person died — and left his bones and DNA — matched where he was born. Carter argued the stories of the Flood and the Tower of Babel point to the reality that mass migrations occurred even in ancient times.

There were other omissions in the genetic family tree, like the lack of any lines drawn out of Australia. Wong said the research team just didn’t have any indigenous Australian DNA samples, but with more data, future iterations of the family tree will be fuller and more accurate.

Even so, Wong and co-author Dr. Anthony Wilder Wohns admit they will never have a complete picture because that would require getting a DNA sample of every human ever known.

Which means, just like every family and every human, any future family tree will be imperfect.