Unique genomic configuration revealed by microsatellite DNA in polyploid dogroses, Rosa sect. Caninae

Nybom, Hilde; Esselink, G.; Werlemark, G.; Leus, Leen; Vosman, Ben

doi:10.1111/j.1420-9101.2005.01010.x

Cited by 60 publications

(79 citation statements)

References 39 publications

(71 reference statements)

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“…Ploidy levels were determined by flow cytometry in earlier studies (Nybom et al, 2004(Nybom et al, , 2006. All of these accessions were found to be pentaploid (2n ¼ 5x ¼ 35) except for R. mollis, which was tetraploid (2n ¼ 4x ¼ 28).…”

Section: Methodsmentioning

confidence: 99%

“…Plant material R. canina (accession 1073), R. rubiginosa (0391), R. dumalis (8701), R. sherardii (1402), R. caesia (504) and R. mollis (105) plants were collected as root suckers in the wild and subsequently grown at Balsgård, South Sweden (Nybom et al, 2006). Ploidy levels were determined by flow cytometry in earlier studies (Nybom et al, 2004(Nybom et al, , 2006.…”

Section: Methodsmentioning

confidence: 99%

“…However, recent molecular investigations have shed some light on the origin and structure of the individual subgenomes. Specifically, microsatellite DNA markers (Nybom et al, 2004(Nybom et al, , 2006, RAPD (Werlemark and Nybom, 2001) and nuclear ribosomal RNA genes (rDNA) (Kovarik et al, 2008a) have shown that the bivalent-forming genomes seem to be rather similar across different dogrose species, even those occurring in different subsections. In contrast, distinctly different univalent genomes occur within single genotypes, but also show levels of differentiation that are associated with taxonomic distances between genotypes.…”

Section: Introductionmentioning

confidence: 99%

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Frequent silencing of rDNA loci on the univalent-forming genomes contrasts with their stable expression on the bivalent-forming genomes in polyploid dogroses (Rosa sect. Caninae)

et al. 2009

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The polyploid species in Rosa section Caninae (2n ¼ 21, 28 or 35) are characterized by an unusual reproductive system known as odd (or asymmetric) meiosis. Only two chromosome sets form bivalents in meiosis, whereas the remaining chromosomes are transmitted as univalents through the female germline. Evolution of ribosomal rRNA genes (rDNA) does not seem to be significantly affected by interlocus homogenization in dogroses. As a consequence, most species contain several rDNA families falling into two main clades (b and g) thought to be differentially distributed between bivalent and univalent chromosomes, respectively. Here, we have investigated expression of rRNA gene families in five pentaploid species (R. canina, R. rubiginosa, R. dumalis, R. sherardii and R. caesia, 2n ¼ 35) and in one tetraploid (R. mollis, 2n ¼ 28). Using extensive sequencing of ITS clones and cleaved amplified polymorphism sequence (CAPS) analysis, we found that the b-family was constitutively expressed in all species. However, there was large variation in the expression patterns of families constituting the g-clade. In addition, a single family can be active in one species, whereas silenced in another. The data show that the families on bivalent-forming chromosomes dominate rDNA expression in all dogrose species. We hypothesize that genes on bivalent genomes are stably expressed, whereas those on univalent genomes undergo variable levels of epigenetic silencing. Nonetheless, mosaic expression of univalent genomes could contribute to phenotypic variation between the species.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Frequent silencing of rDNA loci on the univalent-forming genomes contrasts with their stable expression on the bivalent-forming genomes in polyploid dogroses (Rosa sect. Caninae)

et al. 2009

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“…In addition, since we study a polyploid species, counting the number of alleles does not take into account that some alleles may be present in the genome more than once. Therefore, microsatellite DNA Allele Counting using Peak Ratios (MAC-PR) [30][31][32] was used as an alternative way to score haplotypes at the individual level. Genetic variability was subsequently quantified as Nei's uncorrected diversity index,…”

Section: Individual Genetic Diversitymentioning

confidence: 99%

Associations between Floral Asymmetry and Individual Genetic Variability Differ among Three Prickly Pear (Opuntia echios) Populations

Helsen

Dongen

2016

Symmetry

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While stress is expected to increase developmental instability (DI), not all studies confirm this. This heterogeneity could in part be due to the use of subtle differences between the left and right side of bilateral symmetrical organisms to quantify DI, leading to large sampling error obscuring associations with DI. Traits that develop simultaneously more than twice (such as flower petals or bird feathers) reflect individual DI more reliably, such that stronger associations are expected to emerge. Furthermore, some studies have shown differences in strengths of associations among populations. We studied the association between individual genetic diversity and DI in flower petals within three Opuntia echios populations inhabiting Galápagos. Quantifying individual DI through variation in length and width of a high number of petals within individual cacti, lead to a strong association between DI and genetic diversity in one population. We conclude that associations between individual DI and genetic diversity can be more easily revealed by measuring traits that develop repeatedly.

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“…All dogrose species have the peculiar ' canina meiosis' described more than 80 years ago [Täckholm, 1920]. In pollen mother cells (PMCs), only 7 bivalents are formed, while the other chromosomes remain as univalents and are excluded from pollen [Nybom et al, 2004[Nybom et al, , 2006Ritz and Wissemann, 2011]. Thus, pollen cells carry 7 chromosomes only, derived from the segregation of the bivalent-forming chromosomes.…”

mentioning

confidence: 99%

High Penetrance of a Pan-Canina Type rDNA Family in Intersection Rosa Hybrids Suggests Strong Selection of Bivalent Chromosomes in the Section Caninae

Khaitová

Werlemark²,

Kovaříková³

et al. 2014

Cytogenet Genome Res

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All dogroses (Rosa sect. Caninae) are characterized by the peculiar canina meiosis in which genetic material is unevenly distributed between female and male gametes. The pan-canina rDNA family (termed beta) appears to be conserved in all dogroses analyzed so far. Here, we have studied rDNAs in experimental hybrids obtained from open pollination of F1 plants derived from 2 independent intersectional crosses between the pentaploid dogrose species (2n = 5x = 35) Rosa rubiginosa as female parent (producing 4x egg cells due to the unique asymmetrical canina meiosis) and the tetraploid (2n = 4x = 28) garden rose R. hybrida ‘André Brichet' as male parent (producing 2x pollen after normal meiosis). We analyzed the structure of rDNA units by molecular methods [CAPS and extensive sequencing of internal transcribed spacers (ITS)] and determined the number of loci on chromosomes by FISH. FISH showed that R. rubiginosa and ‘André Brichet' harbored 5 and 4 highly heteromorphic rDNA loci, respectively. In the second generation of hybrid lines, we observed a reduced number of loci (4 and 5 instead of the expected 6). In R. rubiginosa and ‘André Brichet', 2-3 major ITS types were found which is consistent with a weak homogenization pressure maintaining high diversity of ITS types in this genus. In contrast to expectation (the null hypothesis of Mendelian inheritance of ITS families), we observed reduced ITS diversity in some individuals of the second generation which might derive from self-fertilization or from a backcross to R. rubiginosa. In these individuals, the pan-canina beta family appeared to be markedly enriched, while the paternal families were lost or diminished in copies. Although the mechanism of biased meiotic transmission of certain rDNA types is currently unknown, we speculate that the bivalent-forming chromosomes carrying the beta rDNA family exhibit extraordinary pairing efficiency and/or are subjected to strong selection in Caninae polyploids.

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Unique genomic configuration revealed by microsatellite DNA in polyploid dogroses, Rosa sect. Caninae

Cited by 60 publications

References 39 publications

Frequent silencing of rDNA loci on the univalent-forming genomes contrasts with their stable expression on the bivalent-forming genomes in polyploid dogroses (Rosa sect. Caninae)

Frequent silencing of rDNA loci on the univalent-forming genomes contrasts with their stable expression on the bivalent-forming genomes in polyploid dogroses (Rosa sect. Caninae)

Associations between Floral Asymmetry and Individual Genetic Variability Differ among Three Prickly Pear (Opuntia echios) Populations

High Penetrance of a Pan-<b><i>Canina</i></b> Type rDNA Family in Intersection <b><i>Rosa</i></b> Hybrids Suggests Strong Selection of Bivalent Chromosomes in the Section <b><i>Caninae</i></b>

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