title: Characterization of Heterochromatin in the Salivary Gland Chromosomes of Chironomus riparius Meigen and Chironomuspiger Strenzke (Diptera, Chironomidae) by Differential and Fluorochrome Staining.
abstract: The constitutive heterochromatin of two homosequential sibling species, Chironomus riparius and Chironomus piger, was studied. The salivary gland chromosomes of both species were analyzed using three staining methods: orcein and C band staining combined with DAPI and CMA3 fluorochrome staining. Both species have the chromosome set 2n = 8, with the same banding pattern and chromosome arm combinations: AB, CD, EF, G, but they differed in number and distribution of heterochromatic bands, AT-rich sequences (DAPI+) and GC-rich sequences (CMA3+). In the polytene chromosomes of C. piger, C-bands were found in centromeres only. They contain two types of repetitive DNA sequences: DAPI+ (very weak) and CMA3+ sequences. However, the polytene chromosomes of C. riparius have many interstitial heterochromatic bands in addition to the centromeric heterochromatin. Some of these bands contain both AT-rich and GC-rich sequences, while others are either AT-rich (DAPI+) or GC-rich (CMA3+). Therefore, these closely related species differ both in the content and localization of constitutive heterochromatin. The species-specific organization of the constitutive heterochromatin can be used as an additional cytogenetic marker for species differentiation.
authors.forename: Paraskeva
authors.initials: P
authors.lastname: Michailova
authors.forename: Julia
authors.initials: J
authors.lastname: Ilkova
authors.forename: Anna
authors.initials: A
authors.lastname: Maryańska-Nadachowska
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Warchałowska-Śliwa
mesh_terms: D000818:Animals; D002683:Chironomidae / Q000235:genetics* / Q000502:physiology*; D002871:Chromosome Banding; D020732:Cytogenetic Analysis; D006570:Heterochromatin / Q000502:physiology*; D007814:Larva; D012469:Salivary Glands / Q000166:cytology*; D013045:Species Specificity
chemical_list: D006570:Heterochromatin