title: Diversity of a complex centromeric satellite and molecular characterization of dispersed sequence families in sugar beet (Beta vulgaris).
abstract: OBJECTIVE
  The aim of this work was the identification and molecular characterization of novel sugar beet (Beta vulgaris) repetitive sequences to unravel the impact of repetitive DNA on size and evolution of Beta genomes via amplification and diversification.
  
  
  METHODS
  Genomic DNA and a pool of B. vulgaris repetitive sequences were separately used as probes for a screening of high-density filters from a B. vulgaris plasmid library. Novel repetitive motifs were identified by sequencing and further used as probes for Southern analyses in the genus Beta. Chromosomal localization of the repeats was analysed by fluorescent in situ hybridization on chromosomes of B. vulgaris and two other species of the section Beta.
  
  
  RESULTS
  Two dispersed repetitive families pDvul1 and pDvul2 and the tandemly arranged repeat family pRv1 were isolated from a sugar beet plasmid library. The dispersed repetitive families pDvul1 and pDvul2 were identified in all four sections of the genus Beta. The members of the pDvul1 and pDvul2 family are scattered over all B. vulgaris chromosomes, although amplified to a different extent. The pRv1 satellite repeat is exclusively present in species of the section Beta. The centromeric satellite pBV1 by structural variations of the monomer and interspersion of pRv1 units forms complex satellite structures, which are amplified in different degrees on the centromeres of 12 chromosomes of the three species of the Beta section.
  
  
  CONCLUSIONS
  The complexity of the pBV1 satellite family observed in the section Beta of the genus Beta and, in particular, the strong amplification of the pBV1/pRv1 satellite in the domesticated B. vulgaris indicates the dynamics of centromeric satellite evolution during species radiation within the genus. The dispersed repeat families pDvul1 and pDvul2 might represent derivatives of transposable elements.
authors.affiliation: Institute of Botany, Dresden University of Technology, D-01062 Dresden, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Menzel
authors.forename: Daryna
authors.initials: D
authors.lastname: Dechyeva
authors.forename: Torsten
authors.initials: T
authors.lastname: Wenke
authors.forename: Daniela
authors.initials: D
authors.lastname: Holtgräwe
authors.forename: Bernd
authors.initials: B
authors.lastname: Weisshaar
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmidt
mesh_terms: D027461:Beta vulgaris / Q000235:genetics*; D002503:Centromere / Q000235:genetics; D002871:Chromosome Banding; D032461:Chromosomes, Plant / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics*; D004276:DNA, Satellite / Q000235:genetics*; D018745:Genome, Plant; D015698:Genomic Library; D017404:In Situ Hybridization, Fluorescence; D016133:Polymerase Chain Reaction; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D018744:DNA, Plant; D004276:DNA, Satellite