title: On the allopolyploid origin and genome structure of the closely related species Hordeum secalinum and Hordeum capense inferred by molecular karyotyping.
abstract: To provide additional information to the many phylogenetic analyses conducted within Hordeum , here the origin and interspecific affinities of the allotetraploids Hordeum secalinum and Hordeum capense were analysed by molecular karyotyping.
  
  
  
  Karyotypes were determined using genomic in situ hybridization (GISH) to distinguish the sub-genomes and , plus fluorescence in situ hybridization (FISH)/non-denaturing (ND)-FISH to determine the distribution of ten tandem repetitive DNA sequences and thus provide chromosome markers.
  
  
  
  Each chromosome pair in the six accessions analysed was identified, allowing the establishment of homologous and putative homeologous relationships. The low-level polymorphism observed among the H. secalinum accessions contrasted with the divergence recorded for the sub-genome of the H. capense accessions. Although accession H335 carries an intergenomic translocation, its chromosome structure was indistinguishable from that of H. secalinum .
  
  
  
  Hordeum secalinum and H. capense accession H335 share a hybrid origin involving Hordeum marinum subsp. gussoneanum as the genome donor and an unidentified genome progenitor. Hordeum capense accession BCC2062 either diverged, with remodelling of the sub-genome, or its genome was donated by a now extinct ancestor. A scheme of probable evolution shows the intricate pattern of relationships among the Hordeum species carrying the genome (including all H. marinum taxa and the hexaploid Hordeum brachyantherum ).
authors.affiliation: Department of Biomedicine and Biotechnology, University of Alcalá, 28871 Alcalá de Henares (Madrid), Spain.
authors.forename: Ángeles
authors.initials: Á
authors.lastname: Cuadrado
authors.affiliation: Department of Biomedicine and Biotechnology, University of Alcalá, 28871 Alcalá de Henares (Madrid), Spain.
authors.forename: Alfredo
authors.initials: A
authors.lastname: de Bustos
authors.affiliation: Department of Biomedicine and Biotechnology, University of Alcalá, 28871 Alcalá de Henares (Madrid), Spain.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Jouve
mesh_terms: D005075:Biological Evolution; D018745:Genome, Plant; D001467:Hordeum / Q000145:classification* / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D010802:Phylogeny; D011123:Polyploidy
keywords: Allopolyploids; FISH; GISH; Hordeum brachyantherum subsp. brachyantherum; Hordeum marinum subsp. gussoneanum; Hordeum marinum subsp. marinum; ND-FISH