Crusader Y chromosomes in Lebanon

The most comprehensive genetic study yet on the world's ancient crossroads - Lebanon - reveals the legacies left by travellers to and invaders of Lebanon - showing that the Crusaders left chromosomes as well as castles. The results were obtained by a global team of Genographic scientists, led by Dr. Pierre Zalloua of Lebanese American University, Beirut and Dr. Chris Tyler-Smith of the Wellcome Trust Sanger Institute, Hinxton, near Cambridge, UK.

Crusader Y chromosomes in Lebanon

 

crusader-map_300.pngNational Geographic Society
Map of the Crusader Y chromosomes in Lebanon

While all religious communities living in Lebanon carry very similar genetic markers, the new analysis of 926 men from the Christian, Muslim and Druze communities of Lebanon reveals that recent historical migrations had detectable consequences. Lebanese Christian men are more likely to carry genetic signatures found in Europe - and thought to have been carried there by the Crusades; Lebanese Muslim men are more likely to carry genetic signatures deriving from the Muslim expansions of the 7th and 8th centuries. This is one of the few times that scientists have been able to relate distinct genetic patterns to well-documented population movements within a geographic region.

"We are fortunate that the history of Lebanon is so well documented. History gives us a perfect starting point and historians have known about these migrations for centuries. Now we geneticists can detect them as well. It shows how powerful genetics has become and is great news for future studies of places where we don't know so much about the history."

Genographic Associate Researcher Chris Tyler-Smith, at the Wellcome Trust Sanger Institute ​

The analysis of the Y chromosome, a "genetic surname" specific to men, reveals that Lebanese populations are very closely related, and the novel findings result from a detailed analysis of many more markers and many more people than has been attempted before. However, over the past 1400 years geographically distinct populations from Europe and the Arabian Peninsula have entered Lebanon.

The data revealed several interesting findings. A genetic signature called WES1 that is found only in European populations was found also in Lebanese Christian men. Also, Lebanese Muslim men have very high frequencies of J1, typical of the populations of the Arabian Peninsula that were involved in the Muslim expansion. The study found no impact of the Ottoman expansion from Turkey in the 16th century.

This is the most careful and comprehensive study of these populations ever undertaken, and it's revealed new insights into the complex history of my country. The subtle effects we have detected are really exciting but should not obscure the extensive underlying similarity among all of the populations of present-day Lebanon, a country that for too long has been divided along religious lines."

Pierre Zalloua, Genographic Principal Investigator, Middle East/North Africa

The study made use of comparative data from Genographic public participants living in Europe. Over 8,000 people from France, Italy and the UK have now participated - anonymously - in the project, and a subset of their data was used for comparative purposes to track the expansion of these lineages during the time of the Crusades.

"The massive database that we have assembled from Middle Eastern and European populations, including Genographic public participants, has allowed us to detect the subtle genetic impact of these historical events. This study illustrates the power of large amounts of data, and demonstrates how public participants from around the world can help to decipher historical migratory events."

Dr Spencer Wells, Genographic Project Director

Notes to Editors
Publications
  • Y-chromosomal diversity in Lebanon is structured by recent historical events.

    Zalloua PA, Xue Y, Khalife J, Makhoul N, Debiane L et al.

    American journal of human genetics 2008;82;4;873-82

Funding

This project was supported in part by a grant from the National Geographic Committee for Research and Exploration; YX and CTS were supported by the Wellcome Trust. We thank Janet Ziegle and Applied Biosystems for providing STR genotyping and QA support. The Genographic Project is supported by funding from the National Geographic Society, IBM, and the Waitt Family Foundation.

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