title: The influence of natural barriers in shaping the genetic structure of Maharashtra populations.
abstract: BACKGROUND
  The geographical position of Maharashtra state makes it rather essential to study the dispersal of modern humans in South Asia. Several hypotheses have been proposed to explain the cultural, linguistic and geographical affinity of the populations living in Maharashtra state with other South Asian populations. The genetic origin of populations living in this state is poorly understood and hitherto been described at low molecular resolution level.
  
  
  RESULTS
  To address this issue, we have analyzed the mitochondrial DNA (mtDNA) of 185 individuals and NRY (non-recombining region of Y chromosome) of 98 individuals belonging to two major tribal populations of Maharashtra, and compared their molecular variations with that of 54 South Asian contemporary populations of adjacent states. Inter and intra population comparisons reveal that the maternal gene pool of Maharashtra state populations is composed of mainly South Asian haplogroups with traces of east and west Eurasian haplogroups, while the paternal haplogroups comprise the South Asian as well as signature of near eastern specific haplogroup J2a.
  
  
  CONCLUSIONS
  Our analysis suggests that Indian populations, including Maharashtra state, are largely derived from Paleolithic ancient settlers; however, a more recent (∼10 Ky older) detectable paternal gene flow from west Asia is well reflected in the present study. These findings reveal movement of populations to Maharashtra through the western coast rather than mainland where Western Ghats-Vindhya Mountains and Narmada-Tapti rivers might have acted as a natural barrier. Comparing the Maharastrian populations with other South Asian populations reveals that they have a closer affinity with the South Indian than with the Central Indian populations.
authors.affiliation: Centre for Cellular and Molecular Biology, Hyderabad, India. thangs@ccmb.res.in
authors.forename: Kumarasamy
authors.initials: K
authors.lastname: Thangaraj
authors.forename: B Prathap
authors.initials: BP
authors.lastname: Naidu
authors.forename: Federica
authors.initials: F
authors.lastname: Crivellaro
authors.forename: Rakesh
authors.initials: R
authors.lastname: Tamang
authors.forename: Shashank
authors.initials: S
authors.lastname: Upadhyay
authors.forename: Varun Kumar
authors.initials: VK
authors.lastname: Sharma
authors.forename: Alla G
authors.initials: AG
authors.lastname: Reddy
authors.forename: S R
authors.initials: SR
authors.lastname: Walimbe
authors.forename: Gyaneshwer
authors.initials: G
authors.lastname: Chaubey
authors.forename: Toomas
authors.initials: T
authors.lastname: Kivisild
authors.forename: Lalji
authors.initials: L
authors.lastname: Singh
mesh_terms: D000465:Algorithms; D001208:Asia; D041322:Chromosomes, Human, Y / Q000648:ultrastructure; D004272:DNA, Mitochondrial / Q000235:genetics*; D005006:Ethnicity; D005828:Genetics, Population; D005843:Geography; D006239:Haplotypes; D006801:Humans; D007194:India; D018895:Microsatellite Repeats; D008957:Models, Genetic; D015233:Models, Statistical; D010802:Phylogeny; D025341:Principal Component Analysis
chemical_list: D004272:DNA, Mitochondrial