Genetic 'atlas' shows just how much of a hodgepodge we all are

Invasions, mass migrations, and other historical events have contributed to humanity's rich and diverse pool of DNA, a new study shows.

|
Ng Han Guan/AP
This picture taken in 2006 shows Mongolian soldiers in traditional warrior outfit reenact Genghis Khan's legendary conquering hordes in Tov, south of Ulan Bator, Mongolia. About 500 Mongolian soldiers on horsebacks took part in the event to mark the 800th anniversary of the widely revered Mongolian conqueror.

Do you know where your DNA really comes from? A new, interactive "world map" might have an answer. 

In a paper titled "A Genetic Atlas of Human Admixture History" published this week in the journal Science, researchers from Oxford University, University College London, and the Max Planck Institute for Evolutionary Anthropology analyzed the DNA of 1,490 individuals in 95 populations across Europe, Africa, Asia, and South America to understand how populations around the world mixed with each other over the last four millenniums.

The research documents the effect of historical events, such as the Mongol expansion and the Arab slave trade, on the gene pool of the world.

For example – it is widely believed that the Hazara, an ethnic group in Pakistan, are descended in part from Mongol warriors. This study confirmed that Mongol DNA did indeed, enter the population during the period of the Mongol Empire.

“DNA really has the power to tell stories and uncover details of humanity's past”, said Simon Myers of Oxford University's Department of Statistics and Wellcome Trust Centre for Human Genetics, co-senior author of the study.

“Because our approach uses only genetic data, it provides information independent from other sources. Many of our genetic observations match historical events, and we also see evidence of previously unrecorded genetic mixing. For example, the DNA of the Tu people in modern China suggests that in around 1200CE, Europeans similar to modern Greeks mixed with an otherwise Chinese-like population. Plausibly, the source of this European-like DNA might be merchants travelling the nearby Silk Road.”

The researchers used a software called GLOBETROTTER to date events occurring 160 generations ago, or almost 4500 years ago.

"GLOBETROTTER can likely date events somewhat older than this, but this is a rough idea of how old it can go in its current implementation, and technical reasons will make it challenging to go back tens of thousands of years," the authors said. 

Scientists used statistical software to cluster individuals into groups based on the genetic similarity. 

When individuals from different groups interbreed, their children have DNA of both the parents. Researchers looked for these "characteristic signatures" in DNA of the individuals to trace their ancestry.

The team used genome data for all the individuals in order to recognize the "chunks" of DNA that these individuals share with different populations. Therefore, "populations sharing more ancestry share more chunks, and individual chunks give clues about the underlying ancestry along chromosomes," according to a press release from the Max Planck Society is Germany.

Each population has a particular genetic ‘palette’”, said Daniel Falush of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, co-senior author of the study. “If you were to paint the genomes of people in modern-day Maya, for example, you would use a mixed palette with colours from Spanish-like, West African and Native American DNA. This mix dates back to around 1670 AD, consistent with historical accounts describing Spanish and West African people entering the Americas around that time. Though we can’t directly sample DNA from the groups that mixed in the past, we can capture much of the DNA of these original groups as persisting, within a mixed palette of modern-day groups.”

You've read  of  free articles. Subscribe to continue.
Real news can be honest, hopeful, credible, constructive.
What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

QR Code to Genetic 'atlas' shows just how much of a hodgepodge we all are
Read this article in
https://www.csmonitor.com/Science/2014/0213/Genetic-atlas-shows-just-how-much-of-a-hodgepodge-we-all-are
QR Code to Subscription page
Start your subscription today
https://www.csmonitor.com/subscribe