Restriction endonuclease digestion and chromosome banding in the mosquito, Culiseta longiareolata (Diptera: Culicidae)

Publisher Website
Google Scholar
Abstract
Fixed chromosomes of the mosquito, Culiseta longiareolata (2n = 6) were treated in situ with nine restriction endonucleases and stained with ethidium bromide or Giemsa. All the heterochromatic regions were apparently protected from digestion by all enzymes except Mbo I. This enzyme selectively digested one of the three types of heterochromatin present in the species. Staining with the fluorochrome quinacrine after enzyme treatment produced a standard Q-banding pattern or a Hoechst 33258-like pattern, depending on the enzyme. These results confirmed: (a) the presence of three types of heterochromatic containing different DNA fractions in the chromosomes of this species, (b) restriction enzymes accessibility to the DNA of heterochromatin regions, and (c) the selective cleavage of particular DNA fractions without DNA removal. Moreover, quinacrine staining after enzyme digestion proved useful in detecting differential activity among enzymes which produced the same banding pattern with standard dyes.