1.Other Backward Classes (OBC) (about 41.0% of the population)
2. Scheduled Castes (about 19.7% of the population)
3. Scheduled Tribe (about 8.5% of the population)
A study by researchers from the National Institute of BioMedical Genomics (NIBMG) in West Bengal has looked at the genes of various communities to answer questions that have often been suggested in history books: when did caste become the dominant norm for ethnic communities of the region.
For most upper-caste communities, endogamy (that is marrying within one’s caste) started nearly 70 generations ago, or around the time of the Hindu Gupta period around 1,500 years ago, says the study published in the latest issue of the journal PNAS (Proceedings of the National Academy of Sciences of the United States of America).
“A lot of social transformation took place during the Gupta period. Notable among these was the enforcement of social strictures against marriage between castes, as enshrined in the Dharmasastra. This reveals that some social norms leave imprints on the DNA, which can be reconstructed by careful genetic studies,” says Partha P. Majumder, Director, NIBMG, who, along with Analabha Basu and Neeta Sarkar Roy, authored the study.
By looking at the block lengths of ancestral genes, the team could pinpoint the era when mixing of castes ended. In the case of West Bengal Brahmins, marriages with the northeastern communities continued until the arrival of the 8th century Pala dynasty which cut off these regions
of traffic in human beings, all forms pf forced labour and begar. of employment of below the age of 14 years in any factory, or hazardous occupations.
here is ur answer
25 june 1983