title: Characterization of fossilized relatives of the White Spot Syndrome Virus in genomes of decapod crustaceans.
abstract: BACKGROUND
  The White Spot Syndrome Virus (WSSV) is an important pathogen that infects a variety of decapod species and causes a highly contagious disease in penaeid shrimps. Mass mortalities caused by WSSV have pronounced commercial impact on shrimp aquaculture. Until now WSSV is the only known member of the virus family Nimaviridae, a group with obscure phylogenetic affinities. Its isolated position makes WSSV studies challenging due to large number of genes without homology in other viruses or cellular organisms.
  
  
  RESULTS
  Here we report the discovery of an unusually large amount of sequences with high similarity to WSSV in a genomic library from the Jamaican bromeliad crab Metopaulias depressus. De novo assembly of these sequences allowed for the partial reconstruction of the genome of this endogenized virus with total length of 200 kbp encompassed in three scaffolds. The genome includes at least 68 putative open reading frames with homology in WSSV, most of which are intact. Among these, twelve orthologs of WSSV genes coding for non-structural proteins and nine genes known to code for the major components of the WSSV virion were discovered. Together with reanalysis of two similar cases of WSSV-like sequences in penaeid shrimp genomic libraries, our data allowed comparison of gene composition and gene order between different lineages related to WSSV. Furthermore, screening of published sequence databases revealed sequences with highest similarity to WSSV and the newly described virus in genomic libraries of at least three further decapod species. Analysis of the viral sequences detected in decapods suggests that they are less a result of contemporary WSSV infection, but rather originate from ancestral infection events. Phylogenetic analyses suggest that genes were acquired repeatedly by divergent viruses or viral strains of the Nimaviridae.
  
  
  CONCLUSIONS
  Our results shed new light on the evolution of the Nimaviridae and point to a long association of this viral group with decapod crustaceans.
authors.affiliation: Ruhr University Bochum, Department of Animal Ecology, Evolution and Biodiversity, Bochum, Germany. andrey.rozenberg@rub.de.
authors.forename: Andrey
authors.initials: A
authors.lastname: Rozenberg
authors.affiliation: Ruhr University Bochum, Department of Animal Ecology, Evolution and Biodiversity, Bochum, Germany. pbrand@ucdavis.edu.|University of California, Davis, Department of Evolution and Ecology, Center for Population Biology, Davis, USA. pbrand@ucdavis.edu.
authors.forename: Philipp
authors.initials: P
authors.lastname: Brand
authors.affiliation: University of Regensburg, Department of Zoology and Evolutionary Biology, Regensburg, Germany. Nicole.Rivera@biologie.uni-regensburg.de.
authors.forename: Nicole
authors.initials: N
authors.lastname: Rivera
authors.affiliation: Ruhr University Bochum, Department of Animal Ecology, Evolution and Biodiversity, Bochum, Germany. Florian.Leese@rub.de.
authors.forename: Florian
authors.initials: F
authors.lastname: Leese
authors.affiliation: University of Regensburg, Department of Zoology and Evolutionary Biology, Regensburg, Germany. Christoph.Schubart@biologie.uni-regensburg.de.
authors.forename: Christoph D
authors.initials: CD
authors.lastname: Schubart
mesh_terms: D000818:Animals; D033364:Decapoda / Q000821:virology*; D005580:Fossils; D016679:Genome, Viral; D046849:Nimaviridae / Q000235:genetics* / Q000302:isolation & purification*; D016366:Open Reading Frames; D033561:Penaeidae / Q000821:virology; D010802:Phylogeny; D046848:White spot syndrome virus 1 / Q000235:genetics*