Molecular Diversity and Physical Mapping of 5S rDNA in Wild and Cultivated Oat Grasses (Poaceae: Aveneae)

Röser, Martin; Winterfeld, Grit; Grebenstein, Bärbel; Hemleben, Vera

doi:10.1006/mpev.2001.1003

Cited by 57 publications

(56 citation statements)

References 57 publications

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“…In relation to Southern blot analyses, García et al [2009] indicated that a ladder of fragments is expected in species with tandem arrays of 5S rDNA since in most angiosperms these genes contain a single conserved Bam HI site [Röser et al, 2001]. A similar outcome was observed in Citrus medica (used here as an outgroup).…”

Section: Linkage Of 5s and 45s Rdna Sequencesmentioning

confidence: 57%

Karyological Features of Achyrocline (Asteraceae, Gnaphalieae): Stable Karyotypes, Low DNA Content Variation and Linkage of rRNA Genes

Mazzella

Rodríguez

Vaio

et al. 2010

Cytogenet Genome Res

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Many Achyrocline (Asteraceae, tribe Gnaphalieae) species are widely used in Argentina, Brazil and Uruguay as popular medicinal and aromatic plants. Achyrocline flaccida, A. satureioides, A. alata, and A. crassiuscula are distributed in Uruguay and popularly known as ‘marcelas’. In order to characterize them, we performed chromosome counts, compared the karyotypes, mapped the 5S and 45S rDNA sites by fluorescent in situ hybridization, and estimated their DNA content. All species were diploid with 2n = 28 chromosomes, this being the first report for A. flaccida and A. crassiuscula. All species showed symmetrical karyotypes composed exclusively of biarmed chromosomes. DNA content estimated by flow cytometry revealed 2C values ranging from 5.73 to 6.03 pg, the amounts for A. alata and A. crassiuscula being higher than those for the other species. Cytogenetic mapping of 5S and 45S rDNA sequences in three species, A. flaccida, A. satureioides and A. alata, showed that in these species both sites co-localized in the pericentromeric region of chromosome 10. This site corresponds to the only DAPI^– and CMA⁺ band of their genomes. Southern blot hybridization of 5S and 45S rDNA on BamHI digested genomic DNA confirmed the tight linkage of these rDNA families into a single unit. Cytological data indicate that Achyrocline species are karyologically poorly differentiated, whereas the uncommon distribution of 5S and 45S rDNA suggests a close relationship with other genera of the Anthemidae tribe.

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Section: Linkage Of 5s and 45s Rdna Sequencesmentioning

confidence: 57%

Karyological Features of Achyrocline (Asteraceae, Gnaphalieae): Stable Karyotypes, Low DNA Content Variation and Linkage of rRNA Genes

Mazzella

Rodríguez

Vaio

et al. 2010

Cytogenet Genome Res

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“…In all angiosperm species studied, 5S genes contain conserved BamHI sites (Röser et al 2001). Thus, if 5S units were in tandem array, it would be expected that hybridisation of 5S probe against BamHI digested DNA would yield mono-, diand oligomeric bands.…”

Section: Pcr Analysis Of Genomes For Linked 5s-35s Rdna Unitsmentioning

confidence: 99%

“…The unit comprises a ∼5.0-kb genic region encoding for 18S-5.8S-26S genes and a more variable IGS. The 5S rDNA unit is much shorter and is composed of a 120-bp genic region and a 100-1,000-bp spacer (Lapitan 1992;Röser et al 2001;Fulnecek et al 2006). Both the 35S and 5S rRNA genes are tandemly arranged forming clusters of thousands of regularly spaced units.…”

Section: Introductionmentioning

confidence: 99%

Linkage of 35S and 5S rRNA genes in Artemisia (family Asteraceae): first evidence from angiosperms

et al. 2008

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Typically in plants, the 5S and 35S ribosomal DNA (rDNA) encoding two major ribosomal RNA species occur at separate loci. However, in some algae, bryophytes and ferns, they are at the same locus (linked arranged). Southern blot hybridisation, polymerase chain reactions (PCR), fluorescent in situ hybridisation, cloning and sequencing were used to reveal 5S and 35S rDNA genomic organisation in Artemisia. We observed thousands of rDNA units at two-three loci containing 5S rDNA in an inverted orientation within the inter-genic spacer (IGS) of 35S rDNA. The sequenced clones of 26-18S IGS from Artemisia absinthium appeared to contain a conserved 5S gene insertion proximal to the 26S gene terminus (5S rDNA-1) and a second less conserved 5S insertion (5S rDNA-2) further downstream. Whilst the 5S rDNA-1 showed all the structural features of a functional gene, the 5S-rDNA-2 had a deletion in the internal promoter and probably represents a pseudogene. The linked arrangement probably evolved before the divergence of Artemisia from the rest of Asteraceae (>10 Myrs). This arrangement may have involved retrotransposons and once formed spread via mechanisms of concerted evolution. Heterogeneity in unit structure may reflect ongoing homogenisation of variant unit types without fixation for any particular variant.

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“…Autopolyploidy is corroborated by karyotype characteristics ( figs. 2 , 5 ) which unambiguously indicate a presence of the M genome [Röser et al, 2001;Winterfeld et al, 2012].…”

Section: Polyploid Formationmentioning

confidence: 88%

“…However, none of the species complexes distinguished within Helictochloa could be resolved in the molecular phylogenetic studies conducted so far. Analyses of nuclear ribosomal DNAs (rDNAs) [Grebenstein et al, 1998;Röser et al, 2001] suggested for the east Mediterranean to Asian distributed diploid H. aetolica , H. versicolor and H. compressa phylogenetically basal positions within the genus. For polyploid taxa, the presence of multiple DNA copies, maybe due to a low number of taxa and selected clones (copies), was not convincingly shown to date, and relationships based on molecular data remained widely unclear.…”

Section: Introductionmentioning

confidence: 99%

Polyploidy and Hybridization as Main Factors of Speciation: Complex Reticulate Evolution within the Grass Genus Helictochloa

Winterfeld

Schneider

Perner

et al. 2014

Cytogenet Genome Res

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To study the origin and evolution of naturally occurring polyploids, we performed phylogenetic analyses of nuclear ribosomal DNA spacers combined with molecular cytogenetics in 55 accessions of 27 taxa of the oat genus Helictochloa. A complex pattern of reticulate evolution was revealed with many diploid species and extensive polyploidy up to 20x. Altogether 11 groups of internal transcribed spacer (ITS) sequences can be distinguished. Sequences from 1-3 different ITS lineages were detected in polyploids. Cytogenetic data allow reconstruction of 8 basic monoploid chromosome sets. Six of these genomes occur in different combinations in the polyploid species. Two genomes are only found in diploids. Our sequence and karyological data highlight the occurrence of autopolyploidy and allopolyploidy, provide new information about the evolutionary history of taxa, and allow a more accurate systematic treatment of the concerned species. The geographical distribution of the 11 ITS lineages distinguished is highly structured and points to an origin of the genus in western Asia, presumably in grasslands like steppes or mountain steppes and meadows. The evolutionary basal lineages are of Asian, Minor Asian and east Mediterranean distribution and are present also in North America. The western and central parts of the Mediterranean and northern Europe harbor the modern lineages.

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Molecular Diversity and Physical Mapping of 5S rDNA in Wild and Cultivated Oat Grasses (Poaceae: Aveneae)

Cited by 57 publications

References 57 publications

Karyological Features of <i>Achyrocline</i> (Asteraceae, Gnaphalieae): Stable Karyotypes, Low DNA Content Variation and Linkage of rRNA Genes

Karyological Features of <i>Achyrocline</i> (Asteraceae, Gnaphalieae): Stable Karyotypes, Low DNA Content Variation and Linkage of rRNA Genes

Linkage of 35S and 5S rRNA genes in Artemisia (family Asteraceae): first evidence from angiosperms

Polyploidy and Hybridization as Main Factors of Speciation: Complex Reticulate Evolution within the Grass Genus <b><i>Helictochloa</i></b>

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