Jews and Arabs share genes, Stanford research scientist says

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Peter Underhill, a senior research scientist in the department of genetics at Stanford University, has a reality check for the Middle East:

“No matter how you define yourself today — whether Palestinian, Israeli, Syrian, Turkish — Middle Easterners share much of the same gene pool.”

Based on research on the Y chromosome, published by Underhill and Stanford colleagues in a recent issue of Nature Genetics, Underhill said, “There’s no specific molecular signature unique to a particular faith since genes predate more recent events like the invention of monotheism.”

In the midst of the current conflict, it may also serve as an important reminder that “whether Jewish, Christian or Moslem,” people in the Middle East are really of rather close relation, he said.

“It always strikes me how hard it is,” he added, “to find differences between people in genetic sequences.”

Underhill, along with Stanford colleagues and geneticists in the United States, Europe, Israel and Africa, have been working with the paternally transmitted Y chromosomes of more than 1,000 men from 22 geographical areas in order to trace historical migrations and “how we arrived at where we are today.”

They achieved results by testing DNA samples, isolated from white blood cells, from indigenous groups such as aborigines in Australia and Native Americans.

Testing the Y chromosome, said Underhill, is actually fairly new. Generally researchers have concentrated on the X chromosome or on mitochondria, strands in the cytoplasm that contain genetic material.

So why did they study the Y?

“Since only men can get the Y chromosome, and only from your father, the Y is a clearer pathway,” than the maternally transmitted X, which can be inherited by both men and women, he pointed out.

“The clarity of the story is noteworthy.”

For instance, Underhill described a so-called “spelling change in the Y chromosome,” distinctive to many East Asian men.

“Because of a harmless, mutational event — a transcription error — a son inherited a C rather than an A [in his DNA],” he said. “Now when we find men with this marker, we know they come from a common East Asian ancestor.”

So far the scientists have been able to trace worldwide chromosomes of all men back to a common African ancestor, around 59,000 years ago.

“Modern humans, like you and I…even people in the Middle East…have recent African ancestry,” Underhill said. “The root of our tree seems to be in Africa.”

The scientists have also followed the evolution of men after they left Africa, discovering a “distinctive way” that men in various parts of the world “coincide with the origins of other populations.”

“This is kind of like a metaphor for the evolution of our whole species,” said Underhill. “It’s risky to take one system and say this is reminiscent of the origins of populations, but it looks very promising.”

The gene pool of Middle Easterners, in particular, was “rather complex,” said Underhill, describing, “many distinctive Y’s” and “many distinctive characteristics.”

But, Underhill said that most the distinctions found in the Middle East are composed “from mostly contemporary gene pools.”

“The Middle East is a complex region genetically, but it’s also very united,” he said. “Geopolitical boundaries, even religion, are very recent in terms of the time scale we’re looking at.

“Our research goes beyond a geopolitical boundary drawn up by the United Nations.”

Aleza Goldsmith

Aleza Goldsmith is a former J. staff writer.