Global Gene Project to Trace Humanity's Migrations
Hillary Mayell for National Geographic News
|April 13, 2005|
New DNA studies suggest that all humans descended from a single African ancestor who lived some 60,000 years ago. To uncover the paths that lead from him to every living human, the National Geographic Society today launched the Genographic Project at its Washington, D.C., headquarters.
The project is a five-year endeavor undertaken as a partnership between IBM and National Geographic. It will combine population genetics and molecular biology to trace the migration of humans from the time we first left Africa, 50,000 to 60,000 years ago, to the places where we live today.
Ten research centers around the world will receive funding from the Waitt Family Foundation to collect and analyze blood samples from indigenous populations (such as aboriginal groups), many in remote areas. The Genographic Project hopes to collect more than a hundred thousand DNA samples to create the largest gene bank in the world. Members of the public are also being invited to participate.
"Our DNA tells a fascinating story of the human journey: how we are all related and how our ancestors got to where we are today," said American geneticist and anthropologist Spencer Wells, the project leader. "This project will show us some of the routes early humans followed to populate the globe and paint a picture of the genetic tapestry that connects us all."
Wells, a National Geographic explorer-in-residence, feels a certain sense of urgency. Wars, environmental disasters, and increasing globalization are causing more people to move, and the world is gradually becoming less culturally and genetically diverse.
"We need to take a genetic snapshot of who we are as a species before the geographic and cultural context are lost in the melting pot," Wells said. He cites language as a measure of the disappearance of cultures. "There are around 6,000 languages spoken in the world today, and by the end of the century, between half and 90 percent of those are going to be gone."
IBM, as the technology partner of the project, will participate in collecting the data, storing it, and analyzing it.
"We have some indications, from prior studies about the migration of people, how the diversity and similarity that we see in peoples of the world might have happened in the last 50,000 to 10,000 years," said Ajay Royyuru, a senior manager of IBM's Computational Biology Center. "But what is missing is the detail, the ability for everyone on the planet to be able to see, understand, exactly how they got to be where they are."
Tracking Genetic Markers
Each human parent contributes half of a child's DNA, which combines with the other parent's DNA to form a new genetic combination. This so-called recombination gives each of us a unique set of attributes: hair, eye, and skin color; athleticism or lack thereof; susceptibility to certain diseases; and so on.
However, the chunk of DNA known as the y chromosome, which only males possess, is passed from father to son without recombining. The y chromosome, therefore, remains basically unchanged through generations, except for random mutations. Similarly, women pass mitochondrial DNA, which also does not recombine, on to both their sons and daughters.
Random mutations to DNA, which happen naturally and are usually harmless, are called markers. Once a marker has been identified, geneticists can go back in time and trace it to the point at which it first occurred. This way, they are able to determine when and where a new lineage began.
If they can be traced to a particular region, these lineages can be used to track prehistoric migration patterns. However, indigenous identities are being lost as more and more people move from their ancestral villages.
"And when they do [leave], their kids [absorb] the dominant culture in that [new] city and lose touch with the old ways," Wells said. "So what we lose is the context in which their genetic diversity arose. The genes are still going to be there, but without the geographical context, we can't infer anything historical from the genetic data."
Battur Tumer, a descendant of Genghis Khan and one of the participants at the project launch today in Washington, D.C., exemplifies the importance of finding indigenous populations in their ancestral lands.
Wells's team collected y chromosome data in a region of Asia once ruled by the 13th-century Mongolian warrior. Their analysis identified a marker that originated about a thousand years ago and was carried by about 8 percent of the men living in the region. The marker was found in only one population outside of Asiathe Hazaras tribe in Pakistan. The Hazaras have a long oral tradition that says they're Khan's direct descendants.
Tying the marker to a geographic location and looking at the region's historyGenghis Khan's armies often raped the women of vanquished villages, and his descendants later expanded the empiresuggests that today roughly 16 million men carry a genetic mutation that probably originated with Khan's great-great-grandfather.
The spread of that particular mutation was the result of a cultural artifactmilitary success combined with a culture in which men could have many wives and concubinesbut it exemplifies much of the impetus of the Genographic Project.
"The shared marker was identified because a focused effort was made to sample specific populations, going after populations like the Hazara, who have this oral history and want to test it to see if it's true," Wells said.
"In addition, the people in the region had lived there for centuries, and enough samples were collected to do an analysis. The indigenous groups participated because the wanted their stories told."
The Genographic Project is designed to tell everyone's story, though, not just the stories of indigenous cultures. What is unique about this project is the extent to which it relies on public participation.
"Most research happens through the hands of researchers, and the public at large gets to hear about it and learn about it on occasion, but there isn't a way for them to participate. This project is actually inviting individuals all over the world to be sort of associate researchers," Royyuru said. "Success is actually going to be determined by how many and how diverse the people are that participate, which is a fascinating thing."
The DNA data being collected places a person in a "haplogroup"a lineage or branch on the human family tree that is defined by a set of genetic markers. Haplogroup R, for instance, is identified by a y chromosome mutation known as M173. Roughly 70 percent of English men have this lineage, 95 percent of Spanish men, and 95 percent of Irish men.
"The reason a lot of western Europeans have it is because it defines an expansion in the end of the last ice age as people moved north out of Iberia [ancient Spain]," Wells said. "The cool thing is that the penultimate markerif you go back one step from M173is M45, which arose in Central Asia, so it tells you about this journey your ancestors took through the steppes of Central Asia hunting mammoths and so on. Before that they were down in the Middle East."
The Middle Eastern marker, M89, represents a wave of migration out of Africa that occurred around 45,000 years ago. The Haplogroup R lineage ultimately traces all the way back to marker M168.
"Every non-African has M168, which appeared in eastern Africa around 60,000 years ago," Wells said.
"Some geographies have been better studied than others," Royyuru said. "In Europe we have a much better understanding of the genotypic diversity that exists and how that population happens to be so diversewho came from where at what point in time. That is not the case with a large majority of Asia and Africa. There is certainly some understanding of the possible waves of migration and the routes that people might have traveled to populate North and South America, but even those are not definitive."
Should you want to get an idea of your own origins, National Geographic is selling kits that allow an individual to take a cheek swab, send it to a laboratory in Arizona, and then track the information on the Genographic Project Web site.
The kits will sell for U.S. $99.95 plus shipping and handling. The net proceeds from sales of the kits will fund additional research and the Legacy Project, which will aid indigenous cultures.
Legacy and Controversy
"The three main pillars of the project are field research, public participation and communication, and the Legacy Project," Wells said. "We see this as a collaborative effort with the indigenous populations."
The Legacy Project will provide indigenous groups participating in the Genographic Project with direct help through development projects, education, and public-awareness campaigns aimed at preserving traditional cultures.
The idea of creating the world's largest DNA database and collecting blood samples from indigenous groups could raise objections.
Genographic was specifically designed to dispel many of these concerns. The kits are designed so that there's no way to tie a kit's identification number to a specific individual.
Wells emphasizes the public nature of the project.
"We want this to be a very open project. We want to tell the public what it is we're doing, the goals, the methods, and we want to explain the results," Wells said. "We're not doing anything medically relevant, not patenting anything," he added.
"We see this as information that's part of the [common heritage] of our species. It's going to be released into the public domain, and people can go back and reanalyze it and query it and learn about it. We're hoping to create a virtual museum of human history."
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