title: Compact genome of the Antarctic midge is likely an adaptation to an extreme environment.
abstract: The midge, Belgica antarctica, is the only insect endemic to Antarctica, and thus it offers a powerful model for probing responses to extreme temperatures, freeze tolerance, dehydration, osmotic stress, ultraviolet radiation and other forms of environmental stress. Here we present the first genome assembly of an extremophile, the first dipteran in the family Chironomidae, and the first Antarctic eukaryote to be sequenced. At 99 megabases, B. antarctica has the smallest insect genome sequenced thus far. Although it has a similar number of genes as other Diptera, the midge genome has very low repeat density and a reduction in intron length. Environmental extremes appear to constrain genome architecture, not gene content. The few transposable elements present are mainly ancient, inactive retroelements. An abundance of genes associated with development, regulation of metabolism and responses to external stimuli may reflect adaptations for surviving in this harsh environment.
authors.affiliation: 1] Department of Genetics, Stanford University, 300 Pasteur Drive, Stanford, California 94305, USA [2] School of Biological Sciences, Washington State University, 100 Dairy Road, Pullman, Washington 99164, USA.
authors.forename: Joanna L
authors.initials: JL
authors.lastname: Kelley
authors.affiliation: 1] Department of Entomology, Ohio State University, 300 Aronoff Laboratory, 318W. 12th Avenue, Columbus, Ohio 43210, USA [2] Department of Evolution, Ecology and Organismal Biology, Ohio State University, 300 Aronoff Laboratory, 318W. 12th Avenue, Columbus, Ohio 43210, USA [3].
authors.forename: Justin T
authors.initials: JT
authors.lastname: Peyton
authors.affiliation: 1] Department of Biology, Stanford University, 371 Serra St., Stanford, California 94305, USA [2] Institut des Sciences de l'Evolution, UMR5554 CNRS-Université Montpellier 2, Montpellier Cedex 05, France [3].
authors.forename: Anna-Sophie
authors.initials: AS
authors.lastname: Fiston-Lavier
authors.affiliation: 1] Department of Entomology, Ohio State University, 300 Aronoff Laboratory, 318W. 12th Avenue, Columbus, Ohio 43210, USA [2] Department of Entomology and Nematology, University of Florida, Gainesville, Florida 32611, USA.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Teets
authors.affiliation: 1] Department of Genetics, Stanford University, 300 Pasteur Drive, Stanford, California 94305, USA [2] Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.
authors.forename: Muh-Ching
authors.initials: MC
authors.lastname: Yee
authors.affiliation: Department of Entomology, Texas A&M University, College Station, Texas 77843, USA.
authors.forename: J Spencer
authors.initials: JS
authors.lastname: Johnston
authors.affiliation: Department of Genetics, Stanford University, 300 Pasteur Drive, Stanford, California 94305, USA.
authors.forename: Carlos D
authors.initials: CD
authors.lastname: Bustamante
authors.affiliation: Department of Zoology, Miami University, Oxford, Ohio 45056, USA.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Lee
authors.affiliation: 1] Department of Entomology, Ohio State University, 300 Aronoff Laboratory, 318W. 12th Avenue, Columbus, Ohio 43210, USA [2] Department of Evolution, Ecology and Organismal Biology, Ohio State University, 300 Aronoff Laboratory, 318W. 12th Avenue, Columbus, Ohio 43210, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Denlinger
mesh_terms: D000064:Acclimatization / Q000502:physiology; D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology; D000818:Animals; D000864:Antarctic Regions; D002683:Chironomidae / Q000235:genetics* / Q000502:physiology*; D003080:Cold Temperature; D004247:DNA / Q000235:genetics; D004777:Environment; D017344:Genes, Insect / Q000235:genetics; D049750:Genome, Insect / Q000235:genetics* / Q000502:physiology*; D007438:Introns / Q000235:genetics; D005810:Multigene Family / Q000235:genetics
chemical_list: D004247:DNA