Diversity of the repetitive DNA fraction in Cestrum, the genus with the largest genomes within Solanaceae.

Data suggest that the satDNA fraction is conserved in the genus, although there is variation in the number of FISH signals between karyotypes. Except to the absence of FISH signals with probes CsSat1 and CsSat72 in two species, the other satellites occurred in species of different phylogenetic clades. Some satDNA sequences have been detected in the B chromosomes, indicating that they are rich in preexisting sequences in the chromosomes of the A complement. This comparative study provides an important advance in the knowledge on genome organization and heterochromatin composition in Cestrum, especially on the distribution of satellite fractions between species and their importance for the B chromosome composition.