title: Complete genome sequencing and evolutionary analysis of Indian isolates of Dengue virus type 2.
abstract: Dengue is the most important arboviral infection of global public health significance. It is now endemic in most parts of the South East Asia including India. Though Dengue virus type 2 (DENV-2) is predominantly associated with major outbreaks in India, complete genome information of Indian DENV-2 is not available. In this study, the full-length genome of five DENV-2 isolates (four from 2001 to 2011 and one from 1960), from different parts of India was determined. The complete genome of the Indian DENV-2 was found to be 10,670 bases long with an open reading frame coding for 3391 amino acids. The recent Indian DENV-2 (2001-2011) revealed a nucleotide sequence identity of around 90% and 97% with an older Indian DENV-2 (1960) and closely related Sri Lankan and Chinese DENV-2 respectively. Presence of unique amino acid residues and non-conservative substitutions in critical amino acid residues of major structural and non-structural proteins was observed in recent Indian DENV-2. Selection pressure analysis revealed positive selection in few amino acid sites of the genes encoding for structural and non-structural proteins. The molecular phylogenetic analysis based on comparison of both complete coding region and envelope protein gene with globally diverse DENV-2 viruses classified the recent Indian isolates into a unique South Asian clade within Cosmopolitan genotype. A shift of genotype from American to Cosmopolitan in 1970s characterized the evolution of DENV-2 in India. Present study is the first report on complete genome characterization of emerging DENV-2 isolates from India and highlights the circulation of a unique clade in South Asia.
authors.affiliation: Division of Virology, Defence R&D Establishment, Jhansi Road, Gwalior, MP 474002, India. pabandash@rediffmail.com
authors.forename: Paban Kumar
authors.initials: PK
authors.lastname: Dash
authors.forename: Shashi
authors.initials: S
authors.lastname: Sharma
authors.forename: Manisha
authors.initials: M
authors.lastname: Soni
authors.forename: Ankita
authors.initials: A
authors.lastname: Agarwal
authors.forename: Manmohan
authors.initials: M
authors.lastname: Parida
authors.forename: P V Lakshmana
authors.initials: PV
authors.lastname: Rao
mesh_terms: D019943:Amino Acid Substitution; D001483:Base Sequence; D003716:Dengue Virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D019143:Evolution, Molecular; D014644:Genetic Variation; D016679:Genome, Viral; D005838:Genotype; D006801:Humans; D007194:India; D016366:Open Reading Frames; D010802:Phylogeny; D012367:RNA, Viral / Q000032:analysis* / Q000235:genetics; D012641:Selection, Genetic; D017423:Sequence Analysis, RNA; D012689:Sequence Homology, Nucleic Acid; D014759:Viral Envelope Proteins / Q000235:genetics
chemical_list: D012367:RNA, Viral; D014759:Viral Envelope Proteins
keywords: Complete genome; DENV-2; Molecular epidemiology; Phylogeny; Selection pressure