Now, scientists have furnished genetic evidence to show that several thousand years ago, India experienced a change in ways of living, after the caste system came into being.
Marriages between different groups or communities became rarer leading to less mixing of genes between groups. Before this change, people easily married outside of their groups leading to a wider intermixing of genes, they said.
Dr Lalji Singh, molecular biologist, vice- chancellor of Benaras Hindu University Varanasi, and one of the authors of a recent paper on the subject, said in an email to Express, “We have been able to conclude that admixture in North India had occurred approximately 2,000 years ago, while South India saw it approximately 4,000 years ago. Earlier, we had described a mutation (change) which is responsible for sudden cardiac arrest; it originated 30,000 years ago and spread in India, Sri Lanka, Indonesia etc. We also found that the caste system in India is a more recent phenomenon.’’ Singh said that less intermixing has led to the finding of genetically recessive disorders. “Many Indian groups contain genetic variants which account for substantial rates of recessive diseases like Pseudocholinesterase deficiency in the Vysya population of Andhra Pradesh; Familial Madras Motor Neuron Disease (FMMND) that has a unique geographic distribution in Tirupati-Chittoor, Southern India; sickle cell anaemia in some North and Northeast Indian populations, including the tribes of Chhattisgarh; Handigodu syndrome seen in Sagara taluk of Shimoga district of Karnataka; predominance of breast cancer among Parsis and occurrence of sudden cardiac arrests in South Asians.”
Dr Thangaraj who is studying genetic variation at Centre for Cellular and Molecular Biology (CCMB), Hyderabad, said earlier, “The characteristic features in FMMND occur in young children, with weakness and wasting of limbs, multiple lower cranial nerve palsies, tongue atrophy and loss of hearing. The Vysya population in Andhra Pradesh cannot metabolise general anaesthesia and suffer from paralysis of muscles.”
But S Settar, historian at National Institute of Advanced Sciences, Bangalore, said, “One cannot say that caste system controlled genetic intermingling. When invaders or migrants came from countries like Persia, Greece and other European countries, they were generally men and considered Mlecchha or outcastes. After they became a powerful ruling family, they married among other castes and Brahmins and were called as Brahma Kshatriyas. A rigidity of caste was exhibited only by Brahmins and not among Kshatriyas, Vaishyas and Shudras who intermarried quite often.”
He explained: “The early civilised age began in 2 or 3 BC. This is when intermixing began in an orderly form. For example, there is a group of people in Bhatkal in coastal Karnataka called Navayats who don’t marry outside. They are migrants from Persia who married into another trading community of India, the Jains. A new caste system emerged. The women are Jains while the men are Muslims. They eat their meals before sunset, a Muslim custom, while the women avoid meat, a Jain trait! Linking genetic intermixing to caste system is not convincing enough.”