Localization of 45S rDNA and telomeric sites on holocentric chromosomes of Rhynchospora tenuis Link (Cyperaceae)
Genet. mol. biol
; Genet. mol. biol;26(2): 199-201, Jun. 2003. ilus
Article
de En
| LILACS
| ID: lil-345971
Bibliothèque responsable:
BR26.1
RESUMO
Rhynchospora tenuis Link (Cyperaceae) is a weed widely distributed in Brazil that presents a small number of holocentric chromosomes (2n = 4) with some autopolyploid populations (2n = 8). The haploid number n = 2 is considered as a derivative of the base number x = 5. 45S rDNA probes and telomeric DNA were hybridized in both chromosome races of R. tenuis, looking for indications of chromosome fusions. The results showed that hybridization sites of the telomeric probe were restricted to end chromosome regions whereas rDNA sites were terminally located. The chromosome race with n = 4 exhibited a doubled number of sites, with similar size and location to the hybridized sequences, confirming its autopolyploid origin. Furthermore, the terminal location of the single 45S rDNA site in the 2n = 4 race suggested that disploid reduction in Rhynchospora, from n = 5 to n = 2, was followed by elimination or reorganization events, keeping the terminal distribution of these sites, as in an others species of the genus
Texte intégral:
1
Indice:
LILACS
Sujet Principal:
Plantes
/
ADN ribosomique
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Hybridation fluorescente in situ
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Telomerase
Pays comme sujet:
America do sul
/
Brasil
langue:
En
Texte intégral:
Genet. mol. biol
/
Genet. mol. biol. (Online)
/
Genetics and molecular biology (Impresso)
Thème du journal:
GENETICA
Année:
2003
Type:
Article