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The fate of ribosomal RNA genes in spontaneous polyploid dogrose hybrids [Rosa L. sect. Caninae (DC.) Ser.] exhibiting non‐symmetrical meiosis
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| Zeitschriftentitel: | The Plant Journal |
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| Personen und Körperschaften: | , , , , , |
| In: | The Plant Journal, 94, 2018, 1, S. 77-90 |
| Format: | E-Article |
| Sprache: | Englisch |
| veröffentlicht: |
Wiley
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| Schlagwörter: |
| Zusammenfassung: | <jats:title>Summary</jats:title><jats:p>Dogroses represent an exceptional system for studying the effects of genome doubling and hybridization: their asymmetrical meiosis enables recombination in bi‐parentally inherited chromosomes but prevents it in maternally inherited ones. We employed fluorescent <jats:italic>in situ</jats:italic> hybridization, genome skimming, amplicon sequencing of genomic and cDNA as well as conventional cloning of nuclear ribosomal DNA in two phylogenetically distinct pentaploid (2<jats:italic>n</jats:italic> = <jats:italic>5x</jats:italic> = 35) species, <jats:italic>Rosa canina</jats:italic> and <jats:italic>Rosa inodora</jats:italic>, and their naturally occurring reciprocal hybrids, <jats:italic>Rosa dumalis</jats:italic> (<jats:italic>5x</jats:italic>) and <jats:italic>Rosa agrestis</jats:italic> (<jats:italic>5x, 6x</jats:italic>). Both progenitor species differed in composition, meiotic behaviour and expression of rDNA loci: <jats:italic>R. canina</jats:italic> (five 18S and 5–8 5S loci) was dominated by the Canina ribotypes, but <jats:italic>R. inodora</jats:italic> (four 18S loci and 7–8 5S loci) by the Rubiginosa ribotype. The co‐localized 5S/18S loci occurred on either bivalent‐forming (<jats:italic>R. canina</jats:italic>) or univalent‐forming (<jats:italic>R. inodora</jats:italic>) chromosomes. Ribosomal DNA loci were additively inherited; however, the Canina ribotypes were dominantly expressed, even in genotypes with relatively low copy number of these genes. Moreover, we observed rDNA homogenization towards the paternally transmitted Canina ribotype in <jats:italic>6x R. agrestis</jats:italic>. The here‐observed variation in arrangement and composition of rDNA types between <jats:italic>R. canina</jats:italic> and <jats:italic>R. inodora</jats:italic> suggests the involvement of different genomes in bivalent formation. This results supports the hypothesis that the asymmetrical meiosis arose at least twice by independent ancient hybridization events.</jats:p> |
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| Umfang: | 77-90 |
| ISSN: |
0960-7412
1365-313X |
| DOI: | 10.1111/tpj.13843 |