23 January 2020
Middle East history through the genes of its peoples
Published online 23 July 2016
A comprehensive analysis of Middle Eastern genes shows substantial diversity and interbreeding among various sub-regions and with peoples of other continents.
An international consortium of researchers analysed the coding portions of genes, or “exomes”, belonging to 1,794 nationals of Greater Middle Eastern (GME) countries, a region spanning from Morocco in the west to Pakistan in the east1.
“As expected for a region so rich in history and at the crossroads of many civilizations, the Middle East ‘variome’ [the set of genetic variations in a given population] suggests mixing with other populations, although the percentage varies greatly depending on which subpopulation you look at,” says geneticist Fowzan Alkuraya from Saudi Arabia’s King Faisal Specialist Hospital and Research Center.
Northwest African genes were found in people across northern Africa, most likely representing the Berber genetic background. Arabian Peninsular genes were observed in nearly all GME peoples studied, possibly the result of the Arab conquests of the seventh century.
Similarly, Persian expansion in the fifth century into the Turkish peninsula, the Syrian Desert region and parts of northeast Africa probably accounts for the Persian and Pakistan genetic signal present in the peoples of those regions. The peoples of the Syrian Desert and Turkish peninsular regions show the highest levels of mixing with European populations.
The study, however, didn’t find evidence to support a classical theory on “genetic purging”. The theory assumes consanguineous breeding “brings out” the effects of harmful recessive genes, normally hidden in a population. This ultimately leads to a natural selection process that purges a population from the harmful gene. Despite finding strong evidence of recent and historical consanguineous breeding in the region’s genes, the frequency of gene mutations was similar to that in other populations.
“[This] needs to be followed by many more to improve our understanding of the extent of genetic variation in Middle Eastern populations. That is particularly true for rare and ultra-rare variants that can only be captured by sequencing many more individuals than we did in this paper,” says Alkuraya.
- Scott, E. M. et al. Characterization of Greater Middle Eastern genetic variation for enhanced disease gene discovery. Nat. Genet. http://dx.doi.org/10.1038/ng.3592 (2016).