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Insight & Intelligence : May 7, 2014
Genographic Project Records Global Population Gene Flow over Time
Researchers at National Geographic are learning what happened genetically when different cultures appeared.!--h2>
With advanced tools of genetic analysis and a database of more than 600,000 individuals, Spencer Wells, Ph.D., and his team at National Geographic’s Genographic Project (www.genographic.com) are now able to do something that not only has never been thought possible before, they’re able to do something that probably never occurred to people up until a few years ago. In ancestry research, they’ve going from the equivalent of snapshots to a feature length film.
To see this in actual practice, one only needs to take a look at the example of the Mittelelbe-Saale region of Germany. Scientists can easily discover the genetic makeup of the residents there today. Dr. Wells’ Genographic colleagues Wolfgang Haak and Alan Cooper have done something different, and the results have changed our understanding of how humans populated the earth.
As Dr. Wells describes it, “The team looked across a transect in an archeological dig in Germany and, over a span of several thousand years, were able to decipher what happened genetically when different cultures appeared.”
The researchers learned that, 7,500 years ago, the original indigenous hunter-gatherers were largely replaced by farmers coming from what is now Turkey. Then, about 4,800 years ago, a cultural innovation appeared: pottery with a particular corded pattern.
Dr. Wells goes on to say that before researchers were able to extract and analyze maternal mitochondrial DNA from the teeth of skeletons found in the area, we could have assumed that the hunter-gatherers learned to farm and then a few millennia later, learned to make pottery. “What’s truly new in our understanding is the insight that as the cultures changed, the genetic patterns changed,” he explains. “Before, we could see only the end results of who was living where, but we didn’t necessarily understand the ebb and flow of genes over time.”
Solving an Old Debate
Importantly, the genetic research has helped to resolve a 100-year-old debate in archaeological research: do cultures diffuse to people, or do people spread cultures? Dr. Wells and his colleagues used unprecedented numbers of individual genetic samples in their answer to this question, and today we know that, at least in this example from Central Europe, it wasn’t cultures moving among groups, but rather the major cultural changes appear to have come about when new people appeared on the scene, carrying novel genetic lineages. “With modern genetics we are able to see the past dynamics,” says Dr. Wells.
The project that has shed so much light on our human heritage was launched in 2005, a joint project of the National Geographic Society and IBM. In the time since, the Genographic Project has enrolled nearly 600,000 people who’ve paid for a public participation kit, and that’s in addition to the 70,000 indigenous people who have also been tested.
The kit itself enables Genographic researchers to process DNA extracted from a cheek swab that participants mail in. In 2005 there were only a few ancestry-informative genetic markers, but the new Geno 2.0 chip can now rapidly process 140,000 markers optimized for the study of ancestry. This includes mitochondrial information passed down from mother to daughter, Y-chromosome information passed down from father to son, plus information derived from the rest of the genome.
There are many exciting parts of this effort, but among the most exciting in his view is the new power of crowdsourcing. The citizen scientists who have joined the project by purchasing public participation test kits are providing the funding not only to continue the project, but also to help fund cultural preservation projects, including such things as languages and cultural patterns.
Dr. Wells is, of course, deeply pleased that after the startup funding, the current public participation model has enabled the project not only to be self-sustaining but it also is now helping fund additional basic research and on-going testing. He’s particularly proud of the fact that there are so many citizen scientists who are willing to support the effort and care about the research involved.
“They’re interested in their own ancestry, particularly what happened before the genealogy their families were able to tell them about,” he goes on to say, “More than 80% of the kits have been sold in the U.S., although 130 countries are represented. We’re a nation of immigrants and many Americans are trying to discover where their ancestors came from.”
Finding Unsought Patterns
The whole notion of citizens science thrills Dr. Wells. “As scientists we see patterns, and we’re looking for hypotheses we can test. But we are finding that having large numbers of citizens involved means we learn of patterns that we wouldn’t necessarily be looking for on our own,” he notes. “For example, one woman wrote to us saying she was a big fan. But she said, ‘You need to reevaluate your tests because I know my genetic background. You told me that I have a Siberian or a Central Asian genetic lineage, but my family has records including church records that show we came from Hungary. Please retest me.’”
“I got very excited,” recalls Dr. Wells, “not because I wanted the lab to do additional retesting (the result was correct), but because it identified a new pattern. We knew from linguistic data that Hungary is different from the surrounding countries and that people from the Central Asian Steppes have had a huge cultural impact.
“However, up to now we hadn’t seen a significant genetic connection. Because of her question, we pulled the Hungarian population data and saw that 2 to 3% are descendants of people from the Central Asian Steppes.”
Dr. Wells emphasizes that the genetic information we get doesn’t tell a complete story by itself. “The genetic data gives us the who, where, and when, and it also reveals migration patterns. However, to make sense of those patterns requires interpreting the how and the why,” he explains. “Where it truly becomes data rich is when we put it together with information that we now have from paleoclimatology, archeology, paleolinguistics, and paleoanthropology.”
One of the most surprising things that’s come out in the field as a whole is that non-Africans on average have 2% of their genetic material coming from Neanderthals. This likely took place in the Middle East. “We had no idea about this until advances in technology enabled us to see it,” says Dr. Wells.
If his work has transformed ancestry research from family snapshots to a full-length movie, here’s a suggestion for what to name that movie: Where We Came from: The Greatest Journey Ever Told.
Mitzi Perdue, GEN’s corresponding editor, holds degrees from Harvard and George Washington University. She has authored more than 1,600 newspaper and magazine articles on science R&D and clinical medical applications, as well as on food, agriculture, and the environment. Perdue has a strong understanding of complex scientific and mathematical concepts. For 22 years, she was a syndicated columnist for the Scripps Howard News Service and before that, California’s Capitol News. Perdue is also the author of the newsletter from the professional association, Academy of Women’s Health. She has produced and hosted more than 400 interview shows, often in conjunction with scientists at the University of California at Davis. She is a former Commissioner for the U.S. National Commission on Libraries and Information Science and a former Trustee for the National Health Museum.
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