title: Genomic changes in synthetic Arabidopsis polyploids.
abstract: Polyploids are common and arise frequently by genome duplication (autopolyploids) or interspecific hybridization (allopolyploids). Neoallopolyploids display sterility, lethality, phenotypic instability, gene silencing and epigenetic changes. Little is known about the molecular basis of these phenomena, and how much genomic remodeling happens upon allopolyploidization. Extensive genomic remodeling has been documented in wheat, but little remodeling occurs in cotton. Newly synthesized Arabidopsis allopolyploids, which display phenotypic instability and low fertility, displayed several, possibly related mechanisms that can remodel genomes. We detected transcriptional activity of several transposons although their transposition was limited. One represents a new family of conditionally active En-Spm-like transposons of Arabidopsis thaliana, which underwent remodeling of CG methylation upon allopolyploidization. A random amplified fragment length polymorphism survey suggested remodeling at few, specific loci. Meiotic analyses revealed the appearance of chromosomal fragments in a substantial fraction of anther meiocytes. In several individuals produced by hybrids between the synthetic and a natural allopolyploid pollen viability inversely correlated with meiotic instability. Activity of selected DNA transposons and the possibly related chromosomal breaks could cause changes by inducing translocations and rearrangements.
authors.affiliation: Department of Biology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Andreas
authors.initials: A
authors.lastname: Madlung
authors.forename: Anand P
authors.initials: AP
authors.lastname: Tyagi
authors.forename: Brian
authors.initials: B
authors.lastname: Watson
authors.forename: Hongmei
authors.initials: H
authors.lastname: Jiang
authors.forename: Trevor
authors.initials: T
authors.lastname: Kagochi
authors.forename: Rebecca W
authors.initials: RW
authors.lastname: Doerge
authors.forename: Robert
authors.initials: R
authors.lastname: Martienssen
authors.forename: Luca
authors.initials: L
authors.lastname: Comai
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D002874:Chromosome Mapping; D004251:DNA Transposable Elements; D044127:Epigenesis, Genetic; D018745:Genome, Plant; D010802:Phylogeny; D011123:Polyploidy; D019105:Random Amplified Polymorphic DNA Technique; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D004251:DNA Transposable Elements