February 6, 2008
By Syed Akbar
Hyderabad, Feb 5: India got its genes through Indo-Aryans and the Neolithic practices and languages from the Fertile Crescent that makes up the ancient Egypt and the Mediterranean region.
A joint study by S Manjulatha Devi, Irshad Ahmad and others of the city-based Centre for Liver Research and Diagnostics, Deccan College of Medical Sciences and Allied Hospitals, and the Centre for DNA Fingerprinting and Diagnostics, supported the hypotheses related to the gene flow in India through Indo-Aryans.
The scientists conducted the study on Helicobacter pylori, a pathogen that lives in human stomach. The species of H. pylori that is found in present day Indian population is similar to that of the European strain inhabiting the stomachs
of people who live in the West.
"This perhaps conveys the message that H. pylori was most probably introduced to the Indian subcontinent by ancient Indo-European nomadic people and our findings, therefore, are consistent with the idea of a possible gene flow into India with the arrival of Indo-Aryans," the scientists pointed out.
According to the study, H. pylori might have arrived in India probably at the same time when Indo-European language speaking people crossed into India between 4000 and 10,000 years ago. The city scientists arrived at the conclusion as H. pylori co-evolves with its host and thus origins and expansion of multiple populations and sub
populations of the pathogen speak about ancient human migrations.
Since it was not clear how different waves of human migrations in South Asia shaped the population structure of H. pylori, the city scientists went for mapping genetic origins of present day H. pylori in India and its genomic comparison with hundreds of isolates from different geographic regions.
"All the isolates analysed revealed European ancestry and belonged to H. pylori sub-population named hpEurope," they said.
This simple looking organism has now emerged as a reliable biological marker of host-pathogen co-evolution and ancient human migration. It could even provide a window into human origins and migration and the impact of religions and social systems on stratification of human ethnic groups.
The study is consistent with the hypothesis of co-evolution of H. pylori with human beings (Homo sapiens) and thus could form a reliable foundation to test and reconstruct gene flow into India with the arrival of Indo-Aryans or otherwise, they added.
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