ISHS Acta Horticulturae 358: International Symposium on Alliums for the Tropics
PRELIMINARY STUDY FOR THE PHYSICAL ORGANIZATION OF DNA SEQUENCES IN ALLIUM CEPA (ONION) CHROMOSOMES |
| Authors: | A. Ricroch, A. Rouamba, S. Yakovlev, A. Sarr |
| Abstract:
In this preliminary study we examined the physical distribution of repeated DNA sequences along chromosomes of onion ecotypes using several fluorochromes in conjunction with fluorescent in situ hybridization. These preliminary results obtained with Hoechst-labeling (for AT-rich DNA), Chromomycin-labeling (for GC-rich DNA), and C-banding show the same telomeric location of staining in all chromosomes except satellited chromosomes. The nucleolar organizer regions (rDNA genes) were not stained by Hoechst-labeling (for AT-rich DNA). Instead, the regions are GC-rich rDNA repeat units. The structure of repeated DNA sequences in relation with constitutive heterochromatin was discussed. | |
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