Chromatin organization in the holocentric chromosomes of the aphid Schizaphis gruminum has been investigated at a cytological level after C-banding, NOR, Giemsa, DAPI and CMA, staining. C-banding technique showed the presence of numerous C bands on the two X chromosomes both in telomeric and intercalary regions, whereas autosomes show a small number of heterochromatic bands. Contrary to the results with other aphid species, in S. gruminum the C-banding pattern is peculiar to each chromosome pair, thus allowing the identification of homologues and the reliable reconstruction of a karyotype. These cytogenetic data could be useful for the identification of chromosomal rearrangement eventually occurred between different S. gruminum biotypes. Moreover, silver staining and fluorescent in situ hybridization (FISH) with a 28s rDNA probe localized rDNA genes on one telomere of each X chromosome; these are the only brightly fluorescent C-positive regions revealed after CMA, staining, whereas all other heterochromatic bands are DAPI positive
Cytogenetic analysis on holocentric chromosomes in the aphid Schizaphis graminum
Ganassi S;
1999-01-01
Abstract
Chromatin organization in the holocentric chromosomes of the aphid Schizaphis gruminum has been investigated at a cytological level after C-banding, NOR, Giemsa, DAPI and CMA, staining. C-banding technique showed the presence of numerous C bands on the two X chromosomes both in telomeric and intercalary regions, whereas autosomes show a small number of heterochromatic bands. Contrary to the results with other aphid species, in S. gruminum the C-banding pattern is peculiar to each chromosome pair, thus allowing the identification of homologues and the reliable reconstruction of a karyotype. These cytogenetic data could be useful for the identification of chromosomal rearrangement eventually occurred between different S. gruminum biotypes. Moreover, silver staining and fluorescent in situ hybridization (FISH) with a 28s rDNA probe localized rDNA genes on one telomere of each X chromosome; these are the only brightly fluorescent C-positive regions revealed after CMA, staining, whereas all other heterochromatic bands are DAPI positiveI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
