Localization of 45S rDNA and telomeric sites on holocentric chromosomes of Rhynchospora tenuis Link (Cyperaceae)
Genet. mol. biol
; 26(2): 199-201, Jun. 2003. ilus
Article
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| LILACS
| ID: lil-345971
Biblioteca 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
Texto completo:
1
Colección:
01-internacional
Banco de datos:
LILACS
Asunto principal:
Plantas
/
ADN Ribosómico
/
Hibridación Fluorescente in Situ
/
Telomerasa
País/Región como asunto:
America do sul
/
Brasil
Idioma:
En
Revista:
Genet. mol. biol
Asunto de la revista:
GENETICA
Año:
2003
Tipo del documento:
Article
País de afiliación:
Brasil
/
España