March 28, 2008

Genetic Signatures in Lebanon Traced Back to the Crusades

A genetic anthropological study known as The Genographic Project has found what is believed to be faint genetic traces left by medieval crusaders in the Middle East.

The team has uncovered a specific DNA signature in Lebanon that is probably linked to the Christian crusades of the 7th and 8th centuries.

This discovery was noted when researchers found that some Christian men in Lebanon carry a DNA signature originating from Western Europe.

The scientists found that Lebanese Muslim men typically carried a different genetic structure than Christian Lebanese men. This particular structure has been linked to expansions from the Arabian Peninsula which brought Islam to the area.

However, the team emphasized that Christian and Muslim Arabs in Lebanon share a dynamic common heritage and that the differences between the two communities are minor.

Other studies of the genetics of Middle Eastern and North African populations have demonstrated the significant legacy of Muslim Expansion. But evidence of recent European migration to the region is notably unusual.

The Y chromosome (male) was the focus of the study. The package of genetic material carried only by men is passed down from father to son and is left mostly unchanged, much like a surname.

However, over generations, the chromosome accumulates small changes, or copying errors, in its DNA sequence.

Therefore, Y chromosomes are classified into different groups known as haplogroups, which, to some extent, reflect a person's geographical ancestry.

After analyzing the Y chromosomes of 926 Lebanese Males, the scientists discovered that patterns of male genetic variation in Lebanon were more closely related to religious lines than geographical lines.

WES1, a genetic signature on the male chromosome, typically found in European populations, was noted among the Lebanese males used in the study.

"It seems to have come in from Europe and is found mostly in the Christian population," said Dr Spencer Wells, director of the Genographic Project.

"Typically we don't see this sort of stratification by religion when we are looking at the relative proportions of these lineages - and particularly immigration events."

Wells told BBC news that in the same data set a similar enrichment of lineages coming in from the Arabian Peninsula in the Muslim population wasn't seen [as often] in the Christian population.

High frequencies of a Y chromosome grouping known as J1 were found in Lebanese Muslim men"”typical of populations originating from the Arabian Peninsula, who were involved in the Muslim expansion.

"The goal of the study was to put some science to the history of this country - which is very rich," said Pierre Zalloua, a co-author on the paper, from the Lebanese American University in Beirut.

"To have these great civilizations - with the Islamic expansion and the migration from Europe - coming to Lebanon, leaving not only their genes but also some of their culture and way of life, it can only make us feel richer," said Zalloua.

The Genographic Project is a five-year genetic anthropology study that aims to map historical human migration patterns by collecting and analyzing DNA samples from hundreds of thousands of people from around the world.

The company also sells self-testing kits from which a mouth swabbing is obtained, analyzed and the DNA information placed on a web accessible database.


On the Net:

The Genographic Project

Lebanese American University

American Journal of Human Genetics