Light-induced banding (LIB) in metaphase chromosomes of Culiseta longiareolata (Diptera: Culicidae)

The metaphase banding pattern produced in the chromosomes of Culiseta longiareolata (Diptera: Culicidae) by AluI restriction endonuclease or actinomycin-D treatment followed by acridine-orange staining

“…Even though the molecular mechanism of counterstaining procedures may also involve the transfer of electronic energy from AO to Act-D (Sahar & Latt, 1980;Lin et al~ 1980), the longitudinal differentiation we found indicates chromosome areas with larger or smaller amounts of AT or GC base pairs. Therefore, given the characteristics of Act-D/AO counterstaining, as well as the coincidence between Act-D; AO bright areas and 33258 Hoechst bands, we postulate, according to what we already reported (Mezzanotte et al, 1979c(Mezzanotte et al, , 1982a, the existence of an AT-rich DNA in such regions. Moreover, considering that thin Act-D,' AO bright bands coincide with a portion of large Alul bright blocks, we hypothesize that these areas contain a highly repeated, AT-rich DNA.…”