title: Y-chromosomal insights into the genetic impact of the caste system in India.
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.
authors.affiliation: The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambs, CB10 1SA, UK.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Zerjal
authors.forename: Arpita
authors.initials: A
authors.lastname: Pandya
authors.forename: Kumarasamy
authors.initials: K
authors.lastname: Thangaraj
authors.forename: Edmund Y S
authors.initials: EY
authors.lastname: Ling
authors.forename: Jennifer
authors.initials: J
authors.lastname: Kearley
authors.forename: Stefania
authors.initials: S
authors.lastname: Bertoneri
authors.forename: Silvia
authors.initials: S
authors.lastname: Paracchini
authors.forename: Lalji
authors.initials: L
authors.lastname: Singh
authors.forename: Chris
authors.initials: C
authors.lastname: Tyler-Smith
mesh_terms: D041322:Chromosomes, Human, Y / Q000235:genetics*; D005819:Genetic Markers; D005828:Genetics, Population; D006239:Haplotypes; D006801:Humans; D007194:India; D008297:Male; D010802:Phylogeny; D012923:Social Class
chemical_list: D005819:Genetic Markers