title: [Molecular-cytogenetic characteristics of B-chromosomes in chironomid (Diptera, Chironomidae)].
abstract: Morphological and molecular study of B-chromosomes of three Chironomus species (siblings Ch. borokensis and Ch. phumosus from plumosus group, and Ch. heterodentatus from obtusidens group) was carried out. Morphological similarity of B-chromosome banding pattern and telomer-centromeric region banding pattern of chromosome IV in Ch. borokensis was shown. Polytene B-chromosomes of Ch. borokensis and Ch. heterodentatus were microdissected, and their DNA was amplified using degenerate oligonucleotide primer polymerase chain reaction. Comparative analysis of the localization of homologous B-chromosome DNA sequences of A- and B-polytene chromosomes was made using in situ fluorescence hybridization. It has been shown that B-chromosomes in the studied species are composed mainly of repetitive DNA sequences homologous to sequences of centromeric and telomeric DNA of A-chromosomes, and also these of the mobile element NLRCthl. The B-chromosome DNA, homologous to sequences of DNA mobile element, was scattered on A-chromosomes (more than 100 sites). No ribosomal DNA repeats were identified in B-chromosome. Heterologous FISH of B-chromosome DNA to polytene A-chromosomes of Ch. thummi, a species lacking B-chromosomes, enabled us to reveal the presence of numerous sites homologous to DNA of B-chromosomes. These are mainly mobile element sites. An origin of B-chromosomes and peculiarities of their organization in chironomids are discussed.
authors.affiliation: Institute of Cytology and Genetics, Siberian Branch of RAS, Novosibirsk.
authors.forename: M T
authors.initials: MT
authors.lastname: Siirin
authors.forename: N B
authors.initials: NB
authors.lastname: Rubtsov
authors.forename: T V
authors.initials: TV
authors.lastname: Karamysheva
authors.forename: A V
authors.initials: AV
authors.lastname: Katokhin
authors.forename: D A
authors.initials: DA
authors.lastname: Karagodin
authors.forename: I I
authors.initials: II
authors.lastname: Kiknadze
mesh_terms: D000818:Animals; D002503:Centromere / Q000235:genetics; D002683:Chironomidae / Q000235:genetics*; D002871:Chromosome Banding; D002875:Chromosomes / Q000648:ultrastructure*; D004247:DNA / Q000235:genetics*; D015342:DNA Probes / Q000235:genetics; D004251:DNA Transposable Elements / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D012469:Salivary Glands / Q000648:ultrastructure; D016615:Telomere / Q000235:genetics
chemical_list: D015342:DNA Probes; D004251:DNA Transposable Elements; D004275:DNA, Ribosomal; D004247:DNA