Gene study explains spread of Islam

Hyderabad, Oct. 23: The spread of Islam in India was predominantly a cultural conversion associated with minor (but detectable) levels of gene flow primarily from Iran and Central Asia, and not directly from the Arabian peninsula, revealed a new research study done in collaboration by the city-based Centre for Cellular and Molecular Biology (CCMB).

The study also found that most of the Indian Muslim population received its major genetic input from geographically close non-Muslim population. “We have observed low levels of sub-Saharan African, Arabian and West Asian admixture among Indian Muslims. We rule out significant gene flow from Arabia,” said Dr K. Thangaraj, a senior scientist at CCMB.

The CCMB took up the study in collaboration with the National DNA Analysis Centre of the Central Forensic Science Laboratory, Kolkata; State Forensic Laboratory, Lucknow; Leverhulme Centre for Human Evolutionary Studies of University of Cambridge, UK; Department of Evolutionary Biology of Estonian Biocentre and Tartu University, Estonia, and; the Wellcome Trust Sanger Institute, UK.

To estimate the contribution of West Asian and Arabian admixture to Indian Muslims, the team assessed genetic variation in mitochondrial DNA (mother’s lineage), Y-chromosomal (father’s lineage) and genetic markers representing six Muslim communities from different geographical regions of the country.

“Most Indian Muslims are closely related to their neighbouring non-Muslim populations and this suggests that they descend primarily from local Hindu converts. The exception to this are some northern and north-western Indian Muslims, who differ from the indigenous Hindu populations. This is likely because of a higher proportion of genetic lineages of external origin,” the study pointed out. The researchers used 472 Indian Muslim mitochondrial DNAs, 431 Indian Muslim Y chromosomes and 747 Indian Muslim and non-Muslim gene (MCM6) profiles for the study.

“There is a notable variation between different Indian Muslim populations, some being highly similar to local Indian populations and others having similarities with external populations, so that when they are all grouped together as ‘Indian Muslims’, the group difference is statistically insignificant from that of non-Muslims,” said Dr Thangaraj.