engleski

Ribosomal genes and heterochromatin organization on chromosomes of eleven Quercus species

Eleven Quecus species, deciduous as well as evergreen ones, were studied for heterochromatin and ribosomal gene organization by means of fluorochrome banding and fluorescent in situ hybridization (FISH). Curiously, banding patterns, and number and position of ribosomal loci were identical for all the species regardless of their systematic position, geographical origin or ecophysiology. DAPI and CMA bands were juxtapositioned at near-centromeric region of all chromosomes. There were two loci of 18S-5.8S-26S rDNA genes separated on two different chromosome pairs; the major locus at subterminal SC and the minor one at paracentromeric SC. The only 5S rDNA locus appeared at paracentromeric region of the second-sized pair. Ribosomal genes were associated with GC-rich heterochromatin. Considerable progress was done in oak cytogenetics by use of air drying technique for protoplast preparation and by use of FISH. The present work is also the first rapport of physical mapping on oak chromosomes. DAPI banding pattern and FISH markers permitted establishing the karyograms, however, only five pairs were unambiguously identified. The karyograms appeared to be the same among the species studied. Such prominent similarity of chromosome morphology as well as of distribution and position of heterochromatin and ribosomal genes indicates on highly conserved genome organization within Quercus genes.

nije evidentirano

nije evidentirano