By: Qasim Ayub
Image shows the location of Parsi samples from South Asia and an ADMIXTURE plot demonstrating that the Parsis from India and Pakistan are a homogenous population that are genetically closer to present day Iranians. Credit: Gyaneshwer Chaubey et al. (2017)
I have always been fascinated by the Parsi (or Parsee) population of the Indian sub-continent, whom I encountered for the first time when visiting the port city of Karachi in Pakistan as a child with my parents. My recollection was of a cultured, well educated, generous community with their own beliefs and customs and who served delicious mouth-watering food. When I grew up I began to admire their seminal contributions to education, medicine, commerce and the many excellent philanthropic charities they supported.
Who are the Parsis? They are a small ethnic group from South Asia and followers of one of the world’s earliest religion, Zoroastrianism, which flourished in pre-Islamic Persia (present day Iran). Legends record their arrival in Sanjan, off the coast of Gujarat in present day India, during the 7-10th century where they were referred to as ‘Parsi’ (literally meaning ‘people from Paras’, the local term for Persia). Gyaneshwer Chaubey, from the Estonian Biocentre in Tartu, is working on contemporary Parsi samples from India and initiated the collaboration when he found out that I had genotyped Parsi samples from Pakistan. We decided to pool our resources and add results obtained from some ancient DNA extracted from human bones collected from the Sanjan dokhama (tower of silence), a site that the Indian archaeologists concluded was most likely one of the earliest Parsi burial sites in India. These ancient samples were analyzed under the supervision of Dr. Kumarasamy Thangaraj at the CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India. The study was recently published in the journal Genome Biology.
The analyses confirm that the Parsis from India and Pakistan were a homogenous population that were genetically closer to the ancient Neolithic Iranians, followed by present day Near Eastern, Iranian and Caucasian populations, rather than local populations from the vicinity. The results also demonstrate that these migrants genetically admixed with the Indian population about 1,200 years ago, around the time of their reported arrival in the sub-continent as recorded in their legends. This study supports sex-specific admixture and prevailing female gene flow from South Asians to the Parsis, that was observed in earlier studies using male (Y chromosomal) and female (mitochondrial) specific markers. The mitochondrial DNA analysis of the bones recovered from the Parsi burial site indicated that this admixture occurred soon after their arrival.
World Zoroastrian Organisation – Senior Citizens Home, Navsari. Credit: Parzor Foundation, India
This genetic analysis supports the account of the Parsi arrival in India as recorded in the Qissa-e-Sanjan. It records that the local ruler sent a glass full of milk to the Parsi group seeking refuge to indicate that his kingdom was full to the brim and could not accept immigrants. The Zoroastrian priest responded by putting sugar into the full glass of milk to indicate that they would assimilate with the locals like “sugar in milk” and they did indeed do so.
About the authors:
Dr Qasim Ayub has been working with the Human Evolution Team at the Wellcome Trust Sanger Institute since 2008. His research focuses on the analyses of DNA variation in human genomes in order to understand how they adapted to local diets, environments and pathogens as they established themselves in different parts of the world. Qasim continues to maintain his interest in human Y chromosomal variation and South Asian population genomics in health and disease.
Gyaneshwer Chaubey et al. (2017) “Like sugar in milk”: reconstructing the genetic history of the Parsi population. Genome Biology. DOI: 10.1186/s13059-017-1244-9