Caste groups were originally tribal populations: The human story of origin of castes in India

By Syed Akbar

India, with its dozens of populations, presents a veritable museum of
humanity. It is the land of tribals and caste groups, not to speak of the 
numerous religious populations. A little peep into the past and analysis 
of the genetic data of different Indian populations shows that many 
groups, which were originally tribal in nature, have now become caste 
populations. And this transformation from "tribal" to "caste" groups 
may outwardly appear to be a simple sociological phenomenon, but a 
recent study reveals that it has genetic structure too.
The Hyderabad-based anthropology unit of the Indian Statistical 
Institute in its study on north-east Indian populations has established 
the effect of the sociological process of a Tribe-Caste continuum on 
genetic structure.
In north-eastern States of India there are two clusters of populations, 
Caucasoid caste populations on one side and Mongoloid tribal groups 
on the other. In between are the populations which were originally 
tribes but now have become semi-Hinduised caste groups, viz., 
Rajbanshi, Ghutiya, and Ahom. These groups have currently assumed 
caste status and speak Indo-European languages.
According to Dr B Mohan Reddy and Vikrant Kumar of Indian 
Statistical Institute, these tribes over a period of time assumed the 
characteristics and status of castes and this transformation of a tribe 
into a caste results in a Tribe-Caste continuum. A few such cases are 
Bhumij, Kharia, Bauris and Raj Gonds.
"This sociological concept of a Tribe-Caste continuum postulates that 
one end of the continuum is formed by caste populations, while the 
tribal populations constitute the other end. In between are the 
populations who were once tribes but gradually adopted the attributes 
of the caste population and ultimately became absorbed as an integral 
part of a caste system, albeit at the lowest rung of caste hierarchy," they 
point out.
One of the best examples is that of Rajbanshi, which claims to be 
Kshatriya, although a majority of them are Koch. Similar processes 
were reported from other groups such as the Dimasa of Tripura, Jantia 
of Jaintipur and Koch of Cooch Behar. The dwindling of Kachari 
groups from a large number of about 30 to 10 at present is said to be a 
result of this process, they said.  
As part of the study the scientific group examined the gene frequency 
data for 11 genetic markers commonly available in the literature for 22 
populations of north-eastern India in the light of their geographic, 
linguistic, and ethnic affiliations. The markers investigated were blood 
groups, serum proteins and enzyme systems.
The neighbour-joining tree and multidimensional scaling of the 
distance matrix suggest relatively high genetic differentiation among 
the Mongoloid groups, with probably diverse origins when compared 
to the Caucasoid Indo-European populations, which had probably come 
from relatively more homogeneous backgrounds. Broadly speaking, the 
pattern of population affinities conforms to the ethno-historic, 
linguistic, and geographic backgrounds, Dr Mohan Reddy and Vikrant 
Kumar observed. 
The north-eastern part of India is inhabited by numerous endogamous 
tribes and castes that have their own distinct social, linguistic and 
biological identity. It has been hypothesised that a plethora of 
migrations, particularly through the north-east Indian corridor, has 
contributed to the present-day population of north-eastern India. 
Ethnically speaking, most of the tribal groups are Mongoloids, whereas 
caste groups are either Caucasoid or show a mosaic of features of both 
the ethnic groups. The Mongoloids/Indo-Mongoloids have come to 
India from different directions at different times and perhaps earlier 
than the Caucasoid.
While the Mongoloids have migrated from eastern, south-eastern and 
central Asian regions, the Caucasoid may have entered from western 
and northern boundaries of this region. While a majority of the 
Mongoloids are tribes affiliated with the Tibeto-Chinese linguistic 
family, excepting Khasi, most of the Caucasoid are caste groups and 
speak Indo-European languages. Although these groups have been 
broadly classified on the basis of language and ethnicity, they show 
considerable variations within these broad categories, they said.
Both the Mongoloid and Caucasoid groups show a certain degree of 
differentiation within themselves in cultural and biological traits such 
as anthropometry, genetic markers, and dermatoglyphics.
The study also confirms the hypotheses that Mongoloids have entered 
north-eastern India at different points of time by different routes and 
therefore might represent different parental stocks. On the other hand, 
the Caucasoid populations except for the Brahmins and Chetri of 
Sikkim, have migrated from the western route of north-eastern India. 
As far as the Brahmins and Chetri of Sikkim are concerned, they came 
from Northern India to Nepal and then to north-eastern India around 
the 19th century.