The asymmetric meiosis in pentaploid dogroses (Rosa sect. Caninae) is associated with a skewed distribution of rRNA gene families in the gametes
Language English Country England, Great Britain Media print-electronic
Document type Comparative Study, Journal Article, Research Support, Non-U.S. Gov't
PubMed
18648391
DOI
10.1038/hdy.2008.63
PII: hdy200863
Knihovny.cz E-resources
- MeSH
- DNA, Plant genetics MeSH
- Phylogeny MeSH
- Genome, Plant MeSH
- Cloning, Molecular MeSH
- Plant Leaves genetics MeSH
- Meiosis * MeSH
- DNA, Ribosomal Spacer genetics MeSH
- Molecular Sequence Data MeSH
- Multigene Family * MeSH
- Mutation MeSH
- Polyploidy * MeSH
- Pollen genetics MeSH
- RNA, Ribosomal genetics MeSH
- Rosa classification genetics physiology MeSH
- Base Sequence MeSH
- Germ Cells physiology MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Comparative Study MeSH
- Geographicals
- Sweden MeSH
- Names of Substances
- DNA, Plant MeSH
- DNA, Ribosomal Spacer MeSH
- RNA, Ribosomal MeSH
In pentaploid dogroses, Rosa section Caninae (2n=5x=35), the pollen transmits one basic genome (x=7) derived from the seven segregating bivalents, whereas the egg transmits four basic genomes (4x=28) one set derived from the segregation of seven bivalents and three sets of univalent-forming chromosomes. Chromosomes from all five genomes carry 18-5.8-26S nuclear ribosomal DNA (rDNA) sites. This mode of sexual reproduction, known as permanent odd polyploidy, can potentially lead to the independent evolution of rDNA on bivalent- and univalent-forming chromosomes. To test this hypothesis, we analyzed rRNA gene families in pollen and somatic leaf tissue of R. canina, R. rubiginosa and R. dumalis. Six major rRNA gene families (alpha, beta, beta' gamma, delta and epsilon) were identified based on several highly polymorphic sites in the internal transcribed spacers (ITSs). At least two of the major rRNA gene families were found in each species indicating that rDNAs have not been homogenized across subgenomes. A comparison of ITS1 sequences from leaf and pollen showed differences: the shared beta rRNA gene family was more abundant among pollen clones compared to leaf clones and must constitute a major part of the rDNA loci on bivalent-forming chromosomes. The gamma and delta families were underrepresented in pollen genomes and are probably located predominantly (or solely) on the univalents. The results support the hypothesis that pentaploid dogroses inherited a bivalent-forming genome from a common proto-canina ancestor, a likely donor of the beta rDNA family. Allopolyploidy with distantly related species is likely to have driven evolution of Rosa section Caninae.
References provided by Crossref.org
Astonishing 35S rDNA diversity in the gymnosperm species Cycas revoluta Thunb
GENBANK
EU168707, EU168708, EU168709, EU168710, EU168711, FM164423, FM164424, FM164946, FM164947, FM164948, FM164949, FM164950
