title: Genome Sequencing Reveals the Origin of the Allotetraploid Arabidopsis suecica.
abstract: Polyploidy is an example of instantaneous speciation when it involves the formation of a new cytotype that is incompatible with the parental species. Because new polyploid individuals are likely to be rare, establishment of a new species is unlikely unless polyploids are able to reproduce through self-fertilization (selfing), or asexually. Conversely, selfing (or asexuality) makes it possible for polyploid species to originate from a single individual-a bona fide speciation event. The extent to which this happens is not known. Here, we consider the origin of Arabidopsis suecica, a selfing allopolyploid between Arabidopsis thaliana and Arabidopsis arenosa, which has hitherto been considered to be an example of a unique origin. Based on whole-genome re-sequencing of 15 natural A. suecica accessions, we identify ubiquitous shared polymorphism with the parental species, and hence conclusively reject a unique origin in favor of multiple founding individuals. We further estimate that the species originated after the last glacial maximum in Eastern Europe or central Eurasia (rather than Sweden, as the name might suggest). Finally, annotation of the self-incompatibility loci in A. suecica revealed that both loci carry non-functional alleles. The locus inherited from the selfing A. thaliana is fixed for an ancestral non-functional allele, whereas the locus inherited from the outcrossing A. arenosa is fixed for a novel loss-of-function allele. Furthermore, the allele inherited from A. thaliana is predicted to transcriptionally silence the allele inherited from A. arenosa, suggesting that loss of self-incompatibility may have been instantaneous.
authors.affiliation: Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.|Vienna Graduate School of Population Genetics, Institut für Populationsgenetik, Vetmeduni, Vienna, Austria.
authors.forename: Polina Yu
authors.initials: PY
authors.lastname: Novikova
authors.affiliation: Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuchimatsu
authors.affiliation: Université de Lille CNRS, UMR 8198 - Evo-Eco-Paleo, Villeneuve d'Ascq, France.
authors.forename: Samson
authors.initials: S
authors.lastname: Simon
authors.affiliation: Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.
authors.forename: Viktoria
authors.initials: V
authors.lastname: Nizhynska
authors.affiliation: Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.
authors.forename: Viktor
authors.initials: V
authors.lastname: Voronin
authors.affiliation: Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.
authors.forename: Robin
authors.initials: R
authors.lastname: Burns
authors.affiliation: Institute of Biology, Karelian Research Center of the Russian Academy of Sciences,  Republic of Karelia, Petrozavodsk, Russia.
authors.forename: Olga M
authors.initials: OM
authors.lastname: Fedorenko
authors.affiliation: Faculty of Science, Technology and Media, Department of Natural Sciences, Mid Sweden University, Sundsvall, Sweden.
authors.forename: Svante
authors.initials: S
authors.lastname: Holm
authors.affiliation: Department of Biology, Lund University, Lund, Sweden.
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Säll
authors.affiliation: Centre National de Ressources Génomiques Végétales, INRA-CNRGV, Castanet-Tolosan, France.
authors.forename: Elisa
authors.initials: E
authors.lastname: Prat
authors.affiliation: Centre National de Ressources Génomiques Végétales, INRA-CNRGV, Castanet-Tolosan, France.
authors.forename: William
authors.initials: W
authors.lastname: Marande
authors.affiliation: Université de Lille CNRS, UMR 8198 - Evo-Eco-Paleo, Villeneuve d'Ascq, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Castric
authors.affiliation: Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.
authors.forename: Magnus
authors.initials: M
authors.lastname: Nordborg
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D001483:Base Sequence / Q000235:genetics; D002874:Chromosome Mapping / Q000379:methods*; D049810:Genetic Speciation; D014644:Genetic Variation / Q000235:genetics; D016678:Genome / Q000235:genetics; D018745:Genome, Plant / Q000235:genetics; D010802:Phylogeny; D011123:Polyploidy; D057945:Self-Fertilization / Q000235:genetics; D017422:Sequence Analysis, DNA / Q000379:methods; D057891:Tetraploidy
keywords: Arabidopsis arenosa; Arabidopsis suecica; Arabidopsis thaliana; hybridization; polyploidy; shared polymorphism; speciation