title: Deep rooting in-situ expansion of mtDNA Haplogroup R8 in South Asia.
abstract: BACKGROUND
  The phylogeny of the indigenous Indian-specific mitochondrial DNA (mtDNA) haplogroups have been determined and refined in previous reports. Similar to mtDNA superhaplogroups M and N, a profusion of reports are also available for superhaplogroup R. However, there is a dearth of information on South Asian subhaplogroups in particular, including R8. Therefore, we ought to access the genealogy and pre-historic expansion of haplogroup R8 which is considered one of the autochthonous lineages of South Asia.
  
  
  RESULTS
  Upon screening the mtDNA of 5,836 individuals belonging to 104 distinct ethnic populations of the Indian subcontinent, we found 54 individuals with the HVS-I motif that defines the R8 haplogroup. Complete mtDNA sequencing of these 54 individuals revealed two deep-rooted subclades: R8a and R8b. Furthermore, these subclades split into several fine subclades. An isofrequency contour map detected the highest frequency of R8 in the state of Orissa. Spearman's rank correlation analysis suggests significant correlation of R8 occurrence with geography.
  
  
  CONCLUSIONS
  The coalescent age of newly-characterized subclades of R8, R8a (15.4+/-7.2 Kya) and R8b (25.7+/-10.2 Kya) indicates that the initial maternal colonization of this haplogroup occurred during the middle and upper Paleolithic period, roughly around 40 to 45 Kya. These results signify that the southern part of Orissa currently inhabited by Munda speakers is likely the origin of these autochthonous maternal deep-rooted haplogroups. Our high-resolution study on the genesis of R8 haplogroup provides ample evidence of its deep-rooted ancestry among the Orissa (Austro-Asiatic) tribes.
authors: Centre for Cellular and Molecular Biology, Hyderabad, India. thangs@ccmb.res.in
authors: Kumarasamy
authors: K
authors: Thangaraj
authors: Amrita
authors: A
authors: Nandan
authors: Vishwas
authors: V
authors: Sharma
authors: Varun Kumar
authors: VK
authors: Sharma
authors: Muthukrishnan
authors: M
authors: Eaaswarkhanth
authors: Pradeep Kumar
authors: PK
authors: Patra
authors: Sandhya
authors: S
authors: Singh
authors: Sashi
authors: S
authors: Rekha
authors: Monika
authors: M
authors: Dua
authors: Narendra
authors: N
authors: Verma
authors: Alla G
authors: AG
authors: Reddy
authors: Lalji
authors: L
authors: Singh
mesh_terms: D004272:DNA, Mitochondrial / Q000235:genetics*; D006239:Haplotypes; D006801:Humans; D007194:India; D010802:Phylogeny
chemical_list: D004272:DNA, Mitochondrial