Molecular Cytogenetics ofMusaSpecies, Cultivars and Hybrids: Location of 18S-5.8S-25S and 5S rDNA and Telomere-like Sequences

Osuji, Julian O.; Crouch, Jonathan H.; Harrison, G. E.; Heslop-Harrison, J. S.

doi:10.1006/anbo.1998.0674

Cited by 44 publications

(44 citation statements)

References 31 publications

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“…2b). FISH proved valuable for both fundamental and applied aspects of studies of genome evolution and plant breeding (Osuji et al 1998). Besides, this technique is a powerful tool for regional mapping of DNA sequences on chromosomes in interphase and metaphase (Ansari et al 1999, Weiss andMaluszynska 2001).…”

Section: Discussionmentioning

confidence: 99%

Classical and Molecular Cytogenetic Tools to Resolve the Bixa Karyotypes

Almeida

Carvalho

2006

CYTOLOGIA

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SummaryThe cytogenetic studies performed in Bixa orellana have reported 2nϭ14 or 2nϭ16 chromosomes with little karyotypic information. In this context, an improved cytogenetic protocol using enzymatic maceration of meristematic cellular walls and digital image analysis was applied to B. orellana and B. arborea. In B. arborea, the high-resolution technique, Ag-NOR and C banding methods, and FISH using a probe of 45S rDNA genes, were also performed. Prometaphasic and standard C-metaphasic chromosomes presented well-defined primary and secondary constrictions facilitated the pairing of homologues and assembly of the karyogram for the 2 species. These species showed similar karyotypes with 2nϭ14 chromosomes, being composed of 5 metacentric pairs (1, 2, 3, 4 and 6) and 2 submetacentric pairs (5 and 7). The chromosome 1 is approximately 2 times as long as the others and possesses the secondary constriction adjacent to the centromere, which suggests that Robertsonian translocation between 2 smaller chromosomes may have occurred during the karyotype evolution of Bixa. Additionally, the active NOR, the NOR-adjacent heterochromatic region and 18S, 5.8S and 26S rDNA genes were identified in the secondary constriction of chromosome 1.

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Section: Discussionmentioning

confidence: 99%

Classical and Molecular Cytogenetic Tools to Resolve the Bixa Karyotypes

Almeida

Carvalho

2006

CYTOLOGIA

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“…Fluorescent in situ hybridization -FISH was based on the methods of OSUJI et al (1998). rDNA probes containing the ribosomal 18S sequence (1100 pb) of Zea mays were cloned in pGEM ® -T Vector (Promega ® ).…”

Section: Methodsmentioning

confidence: 99%

Morphological aspects ofPassiflora edulisf.flavicarpachromosomes using acridine orange banding and rDNA-FISH tools

et al. 2008

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“…Ribosomal RNA (rDNA) genes containing two different families, 45S and 5S, are found to exist universally in plants, with multiple copies of the coding sequences and intergenic spacers as tandem repeats in the genome (Osuji et al 1998;Katsiotis et al 2000). The 45S rDNA consists of tandem repeat units of the 18S-5.8S-26S rRNA genes and non-transcribed spacers, each unit being typically 10 kb long in plants and responsible for the formation of nucleolar organizer regions (Long and Dawid 1980;Lapitan 1992;Heslop-Harrison 2000).…”

Section: Introductionmentioning

confidence: 99%

Comparative chromosomal localization of 45S and 5S rDNAs and implications for genome evolution inCucumis

Zhang

Yang

et al. 2016

Genome

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Ribosomal DNAs are useful cytogenetic markers for chromosome analysis. Studies investigating site numbers and distributions of rDNAs have provided important information for elucidating genome organization and chromosomal relationships of many species by fluorescence in situ hybridization. But relevant studies are scarce for species of the genus Cucumis, especially in wild species. In the present study, FISH was conducted to investigate the organization of 45S and 5S rDNA among 20 Cucumis accessions, including cultivars and wild accessions. Our results showed that the number of 45S rDNA sites varied from one to five pairs in different accessions, and most of these sites are located at the terminal regions of chromosomes. Interestingly, up to five pairs of 45S rDNA sites were observed in C. sativus var. sativus, the species which has the lowest chromosome number, i.e., 2n = 14. Only one pair of 5S rDNA sites was detected in all accessions, except for C. heptadactylus, C. sp, and C. spp that had two pairs of 5S rDNA sites. The distributions of 5S rDNA sites showed more variation than 45S rDNA sites. The phylogenetic analysis in this study showed that 45S and 5S rDNA have contrasting evolutionary patterns. We find that 5S rDNA has a polyploidizationrelated tendency towards the terminal location from an interstitial location but maintains a conserved site number, whereas the 45S rDNA showed a trend of increasing site number but a relatively conserved location.

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Molecular Cytogenetics ofMusaSpecies, Cultivars and Hybrids: Location of 18S-5.8S-25S and 5S rDNA and Telomere-like Sequences

Cited by 44 publications

References 31 publications

Classical and Molecular Cytogenetic Tools to Resolve the Bixa Karyotypes

Classical and Molecular Cytogenetic Tools to Resolve the Bixa Karyotypes

Morphological aspects ofPassiflora edulisf.flavicarpachromosomes using acridine orange banding and rDNA-FISH tools

Comparative chromosomal localization of 45S and 5S rDNAs and implications for genome evolution inCucumis

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