India and Pakistan genetically linked – by Parsis
doi:10.1038/nindia.2017.67 Published online 15 June 2017
Parsis, a small ethno-religious minority living in India and Pakistan, come from the same original group who landed in Sanjan, in present-day Gujarat, some 1200 years ago, researchers report.
Scientists from the Centre for Cellular and Molecular Biology in Hyderabad, led by Kumarasamy Thangaraj, and colleagues from Estonia, United Kingdom and Pakistan have conducted the first extensive study on Parsis, a community that came to South Asia from Iran.
"Our results are consistent with the historically-recorded migration of the Parsi populations to South Asia in the 7th century and in agreement with their assimilation into the Indian sub-continent's population and cultural milieu "like sugar in milk," the authors report.
With only about 57,264 members, Parsis belong to one of the tiniest religious communities of India, whose fertility and mortality rates have steadily declined over the past century, thus making them vulnerable.
The researchers investigated whether the current Parsi people living in India and Pakistan are genetically related amongst themselves and with the present-day Iranian population, and if their genetic composition has been affected by the neighboring Indian and Pakistani populations.
The scientists analyzed 174 DNA samples from contemporary Indian and Pakistani Parsi populations. They also studied skeletal remains of Parsis excavated from the 'dokhama' (or ‘tower of silence’ where Parsis leave their dead bodies exposed to carrion birds) in Sanjan – the place of their initial settlement in Gujarat.
“We have done extensive analysis using mitochondrial, Y chromosomal and autosomal DNA markers to trace the origin of the Parsi population of the Indian subcontinent and found that they have genetically admixed with the Indian population about 1200 years ago, suggesting that the first Zoroastrian might have arrived India about the same time period,” Thangaraj said.
The study suggested that Parsis of India and Pakistan are from a common stock and collectively showed a significantly closer connection with West Eurasians (Iranians) than to their present geographic neighbours (Sindhis and Gujaratis).
"Our investigation has not only contributed substantial new data, but also provided comprehensive insight into the population structure of Parsis and their genetic links to Iranians and South Asians," the report says.
Villoo Patell, chairman of Bangalore-based Avesthagen Limited, which has an ongoing project on the disease profile of Parsis in India, feels that the sample size used in the study was small. She has expressed interest in extending this study to Avesthagen samples. "We need to see if we get similar results by studying the 4500 (Parsi) samples that we have at Avesthagen, using the same chip they have used."
1. Chaubey, G. et al. “Like sugar in milk”: reconstructing the genetic history of the Parsi population. Genome Biol. doi: 10.1186/s13059-017-1244-9