Chromosome phylogeny of Zamia and Ceratozamia by means of Robertsonian changes detected by fluorescence in situ hybridization (FISH) technique of rDNA

Tagashira, Norikazu; Kondo, Katsuhiko

doi:10.1007/s006060170045

Cited by 35 publications

(33 citation statements)

References 21 publications

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“…Half of the homologous arms are perfectly matched in length (2B-3B, 3b-4b, 5c-6c, 8E-9E, 10F-11F, 11f-12f); thus, the involvement of the chromosomes harbouring them in whole arm rearrangements seems conceivable. In general, models of karyotype evolution are becoming more complex than previously envisaged, as combinations of peri-and/or paracentric inversions and translocations are now thought to be frequent [22,24,36,37]. In both animals and plants, structural rearrangements are among the mechanisms proposed to be involved in relocating rDNA or seeding its parts (if a breakpoint splits a locus into minor ones), creating new rDNA loci [38][39][40][41].…”

Section: Discussionmentioning

confidence: 99%

Ribosomal DNA, tri- and bi-partite pericentromeres in the permanent translocation heterozygote Rhoeo spathacea

Golczyk

Hasterok

Szklarczyk

2010

Cellular and Molecular Biology Letters

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High-and low-stringency FISH and base-specific fluorescence were performed on the permanent translocation heterozygote Rhoeo spathacea (2n = 12).Our results indicate that 45S rDNA arrays, rDNA-related sequences and other GC-rich DNA fraction(s) are located within the pericentromeric regions of all twelve chromosomes, usually colocalizing with the chromomycin A 3 -positive bands. Homogenization of the pericentromeric regions appears to result from the concerted spread of GC-rich sequences, with differential amplification likely. We found new 5S rDNA patterns, which suggest a variability in the breakpoints and in the consequent chromosome reorganizations. It was found that the large 5S rDNA locus residing on each of the 8E and 9E arms consisted of two smaller loci. On each of the two chromosome arms 3b and 4b, in addition to the major subtelomeric 5S rDNA locus, a new minor locus was found interstitially about 40% along the arm length. The arrangement of cytotogenetic landmarks and chromosome arm measurements are discussed with regard to genome repatterning in Rhoeo.

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Section: Discussionmentioning

confidence: 99%

Ribosomal DNA, tri- and bi-partite pericentromeres in the permanent translocation heterozygote Rhoeo spathacea

Golczyk

Hasterok

Szklarczyk

2010

Cellular and Molecular Biology Letters

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“…This is particularly prevalent in the cycad genus Zamia where chromosome numbers include 2n = 16, 18, and 21-28 (Caputo et al, 1996;Tagashira & Kondo, 2001; Fig. 3e), although chromosome number changes between and within cycad genera may also involve more complex rearrangements (Kokubugata & Kondo, 1998).…”

Section: Chromosome Number Diversity -Reduced Diversity In Coniferalesmentioning

confidence: 99%

“…In gymnosperms, unreduced gametes may be produced less frequently. Indeed, we are aware of only one paper reporting (Tagashira & Kondo, 2001). In Cycas revoluta rRNA distal on 4 submetacentric and all 12 telocentric chromosomes (Hizume et al, 1992).…”

Section: Polyploidy and Endoreduplication -Reduced Incidence In Cycadmentioning

confidence: 99%

Ecological and genetic factors linked to contrasting genome dynamics in seed plants

2012

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SummaryThe large-scale replacement of gymnosperms by angiosperms in many ecological niches over time and the huge disparity in species numbers have led scientists to explore factors (e.g. polyploidy, developmental systems, floral evolution) that may have contributed to the astonishing rise of angiosperm diversity. Here, we explore genomic and ecological factors influencing seed plant genomes. This is timely given the recent surge in genomic data. We compare and contrast the genomic structure and evolution of angiosperms and gymnosperms and find that angiosperm genomes are more dynamic and diverse, particularly amongst the herbaceous species. Gymnosperms typically have reduced frequencies of a number of processes (e.g. polyploidy) that have shaped the genomes of other vascular plants and have alternative mechanisms to suppress genome dynamism (e.g. epigenetics and activity of transposable elements). Furthermore, the presence of several characters in angiosperms (e.g. herbaceous habit, short minimum generation time) has enabled them to exploit new niches and to be viable with small population sizes, where the power of genetic drift can outweigh that of selection. Together these processes have led to increased rates of genetic divergence and faster fixation times of variation in many angiosperms compared with gymnosperms.

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“…The preparations were post-denatured on hot plate at 72°C for 2 min and incubated in humid chamber at 37°C overnight. After hybridization, the slides were treated as described in Tagashira and Kondo (2001). Stringent washes were done in 2XSSC at 42 °C for 15 min twice.…”

Section: Plantmentioning

confidence: 99%

Cytogenetic comparison among three cultivars of cucumber (Cucumis sativus L.) by using post-heated DAPI band, 45S and 5S rDNA sites

et al. 2009

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ABSTRACT. The positions of heterochromatic bands, 45S and 5S rDNA regions were detected on the chromosomes in three cultivars of cucumber (Cucumis sativus L.). The post-heated DAPI bands, which revealed heterochromatic region, were observed on the both terminal and pericentromeric regions of most of the chromosomes in three cultivars. However, these band patterns were different between European and Eastern Asian cultivars. The major 45S rDNA sites were found around the centoromeric region of the chromosomes 1, 2 and 5, and the minor 45S rDNA sites were found around centoromeric region of the chromosomes 3 and 7. The positional variation of this region was not found among three cultivars, but size difference was observed in the chromosome 5. The 5S rDNA site was observed on the interstitial region of the chromosome 6 in all of the cultivars studied. These results indicated that the variation of chromosome structure among cucumber cultivars occurred in the heterochromoatic region and suggested that the genetic variation in cucumber cultivars would be revealed by strict analysis and comparison for the position and size of heterochromatic region.

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Chromosome phylogeny of Zamia and Ceratozamia by means of Robertsonian changes detected by fluorescence in situ hybridization (FISH) technique of rDNA

Cited by 35 publications

References 21 publications

Ribosomal DNA, tri- and bi-partite pericentromeres in the permanent translocation heterozygote Rhoeo spathacea

Ribosomal DNA, tri- and bi-partite pericentromeres in the permanent translocation heterozygote Rhoeo spathacea

Ecological and genetic factors linked to contrasting genome dynamics in seed plants

Cytogenetic comparison among three cultivars of cucumber (Cucumis sativus L.) by using post-heated DAPI band, 45S and 5S rDNA sites

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