Pan Africanism : Global Gene Project to Trace Humanity's Migrations...

Discussion in 'Black History - Culture - Panafricanism' started by Aqil, Apr 26, 2005.

  1. Aqil

    Aqil Well-Known Member MEMBER

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    By Hillary Mayell
    National Geographic News

    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, DC 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% 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."

    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 re-combination 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 re-combining. The y chromosome, therefore, remains basically unchanged through generations, except for random mutations. Similarly, females pass mitochondrial DNA, which also does not re-combine, 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 children 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, exemplifies the importance of finding indigenous populations in their ancestral lands. Wells' 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% of the men living in the region. The marker was found in only one population outside of Asia—the Hazaras tribe in Pakistan. The Hazaras have a long oral tradition that says they are Khan's direct descendants. Tying the marker to a geographic location and looking at the region's history—Genghis Khan's armies often raped the women of vanquished villages, and his descendants later expanded the empire—suggests 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 artifact—military success combined with a culture in which men could have many wives and concubines—but 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% of English men have this lineage, 95% of Spanish men, and 95% 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 marker—if you go back one step from M173—is 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 diverse—who 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."

    "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 re-analyze it and query it and learn about it. We're hoping to create a virtual museum of human history."

    http://news.nationalgeographic.com/news/2005/04/0413_050413_genographic.html
     
  2. African_Prince

    African_Prince Well-Known Member MEMBER

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    Did I read right, 50-90% of the 6000 languages spoken around the world will be extinct by the end of the century?
     
  3. Aqil

    Aqil Well-Known Member MEMBER

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    "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% of those are going to be gone."
     
  4. Nisa

    Nisa Well-Known Member MEMBER

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    wow thanks aqil for this powerful powerful info, ill be sure to have members of my family read this. thanks again :bowdown:
     
  5. Aqil

    Aqil Well-Known Member MEMBER

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    You're quite welcome, Nisa...
     
  6. Aqil

    Aqil Well-Known Member MEMBER

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    Geneticists Link Modern Humans to Single Band Out of Africa

    By Nicholas Wade
    May 12, 2005

    A team of geneticists believe they have shed light on many aspects of how modern humans emigrated from Africa by analyzing the DNA of the Orang Asli, the original inhabitants of Malaysia. Because the Orang Asli appear to be directly descended from the first emigrants from Africa, they have provided valuable new clues about that momentous event in early human history.

    The geneticists conclude that there was only one migration of modern humans out of Africa - that it took a southern route to India, Southeast Asia and Australasia, and consisted of a single band of hunter-gatherers, probably just a few hundred people strong. A further inference is that because these events took place during the last Ice Age, Europe was at first too cold for human habitation and was populated only later - not directly from Africa but as an offshoot of the southern migration which trekked back through the lands that are now India and Iran to reach the Near East and Europe.

    The findings depend on analysis of mitochondrial DNA, a type of genetic material inherited only through the female line. They are reported in today's issue of Science by a team of geneticists led by Vincent Macaulay of the University of Glasgow.

    Everyone in the world can be placed on a single family tree, in terms of their mitochondrial DNA, because everyone has inherited that piece of DNA from a single female, the mitochondrial Eve, who lived some 200,000 years ago. There were, of course, many other women in that ancient population, but over the generations one mitochondrial DNA replaced all the others through the process known as genetic drift. With the help of mutations that have built up on the one surviving copy, geneticists can arrange people in lineages and estimate the time of origin of each lineage.

    With this approach, Dr. Macaulay's team calculates that the emigration from Africa took place about 65,000 years ago, pushed along the coastlines of India and Southeast Asia, and reached Australia by 50,000 years ago, the date of the earliest known archaeological site. The Orang Asli - meaning "original men" in Malay - are probably one of the surviving populations descended from this first migration, since they have several ancient mitochondrial DNA lineages that are found nowhere else. These lineages are between 42,000 and 63,000 years old, the geneticists say.

    Groups of Orang Asli like the Semang have probably been able to remain intact because they are adapted to the harsh life of living in forests, said Dr. Stephen Oppenheimer, the member of the geneticists' team who collected blood samples in Malaysia.

    Some archaeologists believe that Europe was colonized by a second migration, which traveled north out of Africa. This fits with the earliest known modern human sites - which date to 45,000 years ago in the Levant and 40,000 years ago in Europe. But Dr. Macaulay's team says there could only have been one migration, not two, because the mitochondrial lineages of everyone outside Africa converge at the same time to the same common ancestors. Therefore, people from the southern migration, probably in India, must have struck inland to reach the Levant, and later Europe, the geneticists say.

    Dr. Macaulay said it was not clear why only one group had succeeded in leaving Africa. One possibility is that since the migration occurred by one population budding into another, leaving people in place at each site, the first emigrants may have blocked others from leaving. Another possibility is that the terrain was so difficult for hunter-gatherers, who must carry all their belongings with them, that only one group succeeded in the exodus.

    Although there is general, but not complete, agreement that modern humans emigrated from Africa in recent times, there is still a difference between geneticists and archaeologists as to the timing of this event. Archaeologists tend to view the genetic data as providing invaluable information about the interrelationship between groups of people, but they place less confidence in the dates derived from genetic family trees.

    There is no evidence of modern humans outside Africa earlier than 50,000 years ago, says Dr. Richard Klein, an archaeologist at Stanford University. Also, if something happened 65,000 years ago to allow people to leave Africa, as Dr. Macaulay's team suggests, there should surely be some record of this event in the archaeological record within Africa, Dr. Klein said. Yet signs of modern human behavior do not appear in Africa until the transition between the Middle and Later Stone Age, 50,000 years ago, he said. "If they want to push such an idea, find me a 65,000-year-old site with evidence of human occupation outside of Africa," Dr. Klein said.

    Geneticists counter that many of the coastline sites occupied by the first emigrants would now lie under water, since sea level has risen more than 200 feet since the last Ice Age. Dr. Klein expressed reservations about this argument, noting that rather than waiting for the rising sea levels to overwhelm them, people would build new sites further inland.

    Dr. Macaulay said that genetic dates have improved in recent years now that it is affordable to decode the whole ring of mitochondrial DNA, not just a small segment as before. But he said he agreed "that archaeological dates are much firmer than the genetic ones" and that it is possible his 65,000-year date for the African exodus is too old.

    Dr. Macaulay's team has been able to estimate the size of the population in Africa from which the founders are descended. The calculation indicates a maximum of 550 women, but the true size may have been considerably less. This points to a single group of hunter-gatherers, perhaps a couple of hundred strong, as the ancestors of all humans outside of Africa, Dr. Macaulay said.

    http://www.nytimes.com/2005/05/12/s...&en=dc84b1703a80659f&ei=5094&partner=homepage
     
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