title: Global distribution of nearly identical phage-encoded DNA sequences.
abstract: Phages, the most abundant biological entities on the planet, play important roles in biogeochemical cycling, horizontal gene transfer, and defining microbial community composition. However, very little is known about phage diversity or biogeography, and there has not yet been a systematic effort to compare the phages found in different ecosystems. Here, we report that T7-like Podophage DNA polymerase sequences occur in every major biome investigated, including marine, freshwater, sediment, terrestrial, extreme, and metazoan-associated. The majority of these sequences belong to a unique clade that is only distantly related to cultured isolates. Some identical T7-like phage-encoded DNA polymerase genes from this clade were >99% conserved at the nucleotide level in multiple different environments, suggesting that these phages are moving between biomes in recent evolutionary time and that the global genomic pool for T7-like phages may be smaller than previously hypothesized.
authors.affiliation: Department of Biology, LS301, Center for Microbial Sciences, San Diego State University, 5500 Campanile Drive, LS301, San Diego, CA 92182-4614, USA.
authors.forename: Mya
authors.initials: M
authors.lastname: Breitbart
authors.forename: Jon H
authors.initials: JH
authors.lastname: Miyake
authors.forename: Forest
authors.initials: F
authors.lastname: Rohwer
mesh_terms: D017124:Conserved Sequence; D004279:DNA, Viral / Q000032:analysis* / Q000235:genetics / Q000302:isolation & purification; D004259:DNA-Directed DNA Polymerase / Q000235:genetics*; D017753:Ecosystem; D004783:Environmental Microbiology; D019143:Evolution, Molecular; D005618:Fresh Water / Q000821:virology; D005814:Genes, Viral; D019015:Geologic Sediments / Q000821:virology; D008969:Molecular Sequence Data; D010802:Phylogeny; D017902:Podoviridae / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D012623:Seawater / Q000821:virology; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
chemical_list: D004279:DNA, Viral; D004259:DNA-Directed DNA Polymerase