INVESTIGADORES
URTUBEY estrella
congresos y reuniones científicas
Título:
Karyotype structure on populations of two species of Hypochaeris (H.catharinensis and H. lutea), Asteraceae from South Brazil
Autor/es:
VIDOTTO, T.; RUAS, E. A.; FIORIN F. G.; RUAS, P. M.; VANZELA, A. L.; M. A. ORTIZ; S. TALAVERA; T. F. STUESSY; E. URTUBEY; K. TREMETSBERGER; N. I. MATZENBACHER; C. F. RUAS
Lugar:
Guaruya
Reunión:
Congreso; 56 Congresso Brasileiro de genética; 2010
Institución organizadora:
Sociedad de genetica
Resumen:
Karyotypes were investigated in ten populations of H. catharinensisand five populations of H. lutea using Feulgen staining, fluorochrome banding (CMA and DAPI) and FISH. The study revealed the typical asymmetrical and bimodal karyotypes with 2n = 8 chromosomes that characterize the South American species of Hypochaeris. One population of H. lutea was entirely polyploid adding up a novel cytotype for this species.CMA banding showed strong signals on both arms of chromosomes 3 and 4 of H. catharinensis, besides many dispersed but less intense signals, revealing a novel pattern in the distribution of GC-rich heterochromatin in Hypochaeris. Except for one population, the CMA banding in H. luteavalidates the pattern already described for this species. DAPI banding was detected the first time in Hypochaeris revealing a weak signal in H. catharinensis and absence of signals in H. lutea. FISH with rDNA inH. catharinensisrevealed a unique locus of 5S rDNA at intercalary position on short arm of pair 2 and a terminal 45S rDNA locus on short arm of pair 3. The presence of unusual large blocks of GC-rich heterochromatin suggests that significant chromosome rearrangements, related to dispersion of heterochromatin, are taking place in the karyotype of H. catharinensis. The novel polyploidcytotype identified in H. luteasuggests that polyploidization is an active process of chromosome evolution in Hypochaeris. Financial support: CAPES, CNPQ.