Chromosome analysis and molecular characterization of highly repeated DNAs in the aphid Acyrthosiphon pisum (Aphididae, Hemiptera).

Despite the interest in aphid biology, information on chromatin organization of their holocentric chromosomes is still limited to few species. In order to fill this gap, we have performed an extensive survey on pea aphid mitotic chromosomes using both classical and molecular cytogenetic techniques. Our results after silver, CMA3 and DAPI-staining, C-banding and fluorescent in situ hybridization (FISH) using 28S rDNA and 5S rDNA as probes evidenced a tendency of repetitive DNAs to be concentrated on the X chromosomes. FISH experiments with the telomeric probe (TTAGG)n revealed bright hybridization signals on each telomere of all Acyrthosiphon pisum chromosomes. No interstitial signals were seen.