A group of researchers have concluded that Thiyyas, Ezhavas, and Nairs from Kerala, and Bunts and Hoysalas from Karnataka in the southwest coast of India are genetically closer to populations of northwest India. The genetic study was conducted by a team of researchers led by Dr Kumarasamy Thangaraj, JC Bose Fellow, CSIR-Centre for Cellular and Molecular Biology (CCMB), Hyderabad. They used blood samples from 213 healthy and unrelated individuals belonging to Nair, Thiyya, Bunt, Ezhava, and Hoysala populations, who historically had the status of traditional warriors and feudal lords, and mostly inhabit the Konkan and Malabar regions of Karnataka and Kerala. The findings were recently published in the journal Genome Biology and Evolution.
In their study, the researchers have pointed out that the south-west coast of India is a region of high population diversity and with complex genetic history, which has happened due to migration, admixture, and cultural assimilation and development over a millennium. The region houses several caste groups linguistically belonging to either the Dravidian family (Malayali and Tulu) or Konkani branch of Indo-European language family and historically falling under priestly (Havik and Hoysala), warrior (Nair and Thiyya) and landlord (Bunt) status.
Previous studies on more recent migrants who inhabit southwest India, including Jews, Parsis, and Roman Catholics, also reveal the complex genetic heritage of this region. Research has also suggested multilayered genetic admixture among different caste groups.
Historians and written records relate southwestern coastal groups with traditional 'warrior' and 'feudal lord' status to migrants from Ahichhatra (Iron age civilization) in Gangetic plain, while others relate them to Indo-Scythian clan migrants from northwest India.
In the recent genetic study, the researchers looked for genome-wide autosomal markers and maternally inherited mitochondrial DNA markers, and compared their results with ancient and contemporary Eurasian populations ranging from the Bronze age to present day groups.
“Our genetic study revealed that the Nair and Thiyya warrior communities share most of their ancestry from ancient migrants of northwest India, and have enhanced Iranian ancestry, similar to Kamboj and Gujjar populations,” said Dr Thangaraj.
According to the study, their maternal genome also reflects higher distribution of West Eurasian mitochondrial lineages, suggesting female-mediated migration, unlike most of the recent migrant groups such as Siddis.
“Our machine-learning based study suggests that the migration of these groups happened following northwest to central India to the southwest coast during late Bronze age or probably Iron age,” said Dr Lomous Kumar, first author of the study, who was the PhD student of the CCMB and presently is at the Birbal Sahni Institute of Palaeosciences, Lucknow.
“This study suggests that the southwest coastal groups are remnants of very early migrations from northwest India following the Godavari basin to Karnataka and Kerala,” CCMB Director Dr Vinay K Nandicoori said.
Other researchers who were involved in this study are Dr Moinak Banerjee, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram; and Dr. Mohammed S. Mustak, Mangalore University, Mangaluru.