Abstract
The caste system has persisted in Indian Hindu society for around 3,500 years. Like the Y chromosome, caste is defined at birth, and males cannot change their caste. In order to investigate the genetic consequences of this system, we have analysed male-lineage variation in a sample of 227 Indian men of known caste, 141 from the Jaunpur district of Uttar Pradesh and 86 from the rest of India. We typed 131 Y-chromosomal binary markers and 16 microsatellites. We find striking evidence for male substructure: in particular, Brahmins and Kshatriyas (but not other castes) from Jaunpur each show low diversity and the predominance of a single distinct cluster of haplotypes. These findings confirm the genetic isolation and drift within the Jaunpur upper castes, which are likely to result from founder effects and social factors. In the other castes, there may be either larger effective population sizes, or less strict isolation, or both.
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Acknowledgments
We thank all sample donors for participating in this project, and Kamal Bagai for help with sample collection. We also thank Ed Southern for his interest and contribution to this work, Yali Xue with advice on data analysis and Denise Carvalho-Silva for comments on the manuscript. TZ and CTS are supported by The Wellcome Trust.
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Tatiana Zerjal and Arpita Pandya contributed equally to this work.
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Zerjal, T., Pandya, A., Thangaraj, K. et al. Y-chromosomal insights into the genetic impact of the caste system in India. Hum Genet 121, 137–144 (2007). https://doi.org/10.1007/s00439-006-0282-2
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DOI: https://doi.org/10.1007/s00439-006-0282-2