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V N Stegniĭ

Publications and source records attributed to V N Stegniĭ.

At least 19 recordsLinked to original sources
PubMed2006

[Localization of repetitive DNA sequences in the pericentromeric heterochromatin of malarial mosquitoes of the "Anopheles maculipennis" complex].

Distribution of eight fragments of conserved repetitive DNA from pericentromeric heterochromatin of chromosome 2 of Anopheles atroparvus has been investigated by in situ hybridization on polytene chromosomes of An. atroparvus and An. messeae. We have shown that heterochromatic regions of all chromosomes both in An. atroparvus and An. messeae vary in combinations of, at least, conserved repeats. Some repeats have been found only in pericentromeric heterochromatic regions of chromosomes 2 (clones Atr2R-46a, Atr2R-73, Atr2R-85a in An. atroparvus and Atr2R-25 in An. messeae). Others have been found in two (clones Atr2R-25a and Atr2R-90 in An. atroparvus, Atr2R-25a in An. messeae) and more (clones Atr2R-118, Atr2R-136 in An. atroparvus, Atr2R-73 in An. messeae) pericentromeric heterochromatic regions of chromosomes. DNA comparison of pericentromeric heterochromatic regions of chromosomes in species of the "Anopheles maculipennis" complex is species- and chromosome-specific, due, in particular, to different maintenance of conserved repeates.

Animals↗
PubMed2006

[Evolutionary significance of chromosome architecture for epigenetic control of eukaryote development and phylogeny].

The significance of the spatial organization of chromosomes in germline tissue as a positional system controlling segregation in oogenesis is considered. The history of the problem is reviewed. The author's data on reorganization of chromosome structure in germline tissue considered in terms of systemic mutations are systematized. The notion of specific morphogenetic field based on chromosome structure, which controls ooplasmic segregation and subsequent developmental stages, is developed.

Animals↗
PubMed2005

[Visualization of chromosome territories in interphase nuclei of ovarian nurse cells in Calliphora erythrocephala Mg. (Diptera: Calliphoridae)].

Analysis of localization of chromosomes 2, 3, and 6 of Calliphora erythrocephala Mg. in ovarian nurse cell nuclei with different chromatin structure has shown that the regions of DNA probe hybridization reduced with increasing chromatin compaction. Hybridization of DNA probes of chromosomes 3 and 6 to secondary reticular nuclei demonstrated that chromosomes retain their territories in the nuclei when the chromatin acquires a reticular structure. These results suggest regular organization of the chromosomal apparatus at all stages of the endomitotic cycle, including the stage of highly polyploid reticular nuclei. FISH of DNA probe of the chromosome 2 telomeric region to secondary reticular nuclei revealed a peripheral distribution of the signal. Zones of more intensive DNA probe hybridization have been distinguished. These zones probably are the regions of accumulation of telomeric and (or) centromeric chromosome regions.

Animals↗
PubMed2004

[Characterization and comparative analysis of DNA from the pericentric heterochromatin of chromosome 2 of Anopheles atroparvus V. Tiel (Culicidae, Diptera)].

The minilibrary containing DNA sequences from the diffuse pericentric heterochromatin from the right arm of Anopheles atroparvus V. Tiel (Culicidae, Diptera) chromosome 2 (2R) was generated by use of chromosome microdissection technique. Southern-blot hybridization of the minilibrary fragments with the labeled genomic DNA of A. atroparvus and analysis of their primary structure showed that this heterochromatin region contained repeated DNA sequences differed by their primary structure and the number of copies. These were mostly AT-rich sequences harboring the features characteristic of the S/MAR regions. Based on the clones homology to the sequences from the An. gambiae and Drosophila melanogaster genomes, it was demonstrated that the pericentric heterochromatin from the right arm of An. atroparvus chromosome 2 contained gypsy-like transposable elements, as well as the sequences homologous to the structural genes. In situ hybridization with the chromosomes of A. atroparvus and of the two representatives of the Anopheles maculipennis species complex, A. messeae and A. beklemishevi, showed that pericentric regions of all these chromosomes contained DNA sequences homologous to the sequences from the region-specific minilibrary. Cloned fragments of conserved repetitive DNA revealed upon interspecific Southern-blot hybridization of the clones with the labeled genomic DNA of A. messeae can be utilized in further investigations of evolutionary rearrangements of the pericentric heterochromatin within the Anopheles maculipennis species complex.

AT Rich Sequence↗
PubMed2003

[Alteration of chromosome structure in ovarian nurse cells of Drosophila melanogaster by hybrid dysgenesis].

The impact of hybrid dysgenesis on the chromosome structure of Drosophila melanogaster ovarian nurse cells was studied. In the examined lines and interlinear hybrids (including those yielded by dysgenic crosses in the P-M and I-R systems of hybrid dysgenesis), disturbed chromosome synapsis was revealed. The disturbance was somewhat similar to that observed in interspecific hybrids. Quantitative analysis showed that the mean frequency of nuclei with defective chromosome pairing ranged from 60.4 to 76%. FISH analysis of ovarian nurse chromosomes of Canton S x Berlin hybrids showed differences in the label localization in asynaptic homologs of arm 2L, which probably results in disrupted homolog pairing and reveal interlinear differences in localization of mobile genetic elements. Our results conform to Sved's model stating that hybrid dysgenesis is based on disorganization of the germline nuclear space.

Animals↗
PubMed2003

[Organization and differential staining of chromosomes from the endomitotic nucleus of trophocytes Calliphora erythrocephala (Diptera: Calliphoridae)].

The structure of primary polytene chromosomes and general architecture of nurse cell nuclei was studied in Calliphora erythrocephala using various methods of differential chromosome banding(G-, R-, C-banding; Ag- and DAPI staining), chromospecific DNA probes and fluorescence in situ hybridization. This analysis revealed differential compaction of particular chromosome regions. The localization of material of polytene chromosome 6 is retained after its rearrangement and the formation of the internal reticular structure of the nucleus. Polytene chromosomes of ovarian nurse cells were shown to have blocks of dense compact material; some of them were more intensely stained by AgNO3. The dynamics of the nucleolus formation was traces at all stages of chromosome polytenization in the C. erythrocephala nurse cells.

Animals↗
PubMed2002

[Chromosome localization of the lambda20p1.4 clone of the Drosophila melanogaster nuclear lamina DNA in the melanogaster species subgroup of the genus Drosophila (Sophophora)].

Chromosome localization of sequences homologous to lambda 20p1.4 of the Drosophila melanogaster nuclear lamina DNA (nlDNA) was established by in situ hybridization in species of the melanogaster subgroup. DNA of the lambda 20p1.4 clone was shown to be located in the chromocenter in all the species examined. Laboratory strains of D. simulans, D. mauritiana, and D. sechellia exhibited interspecific differences in localization of lambda 20p1.4 nlDNA on chromosome arms. In eight natural populations, intraspecific polymorphism of lambda 20p1.4 nlDNA chromosome localization was shown to be present in D. simulans but absent in D. melanogaster. The possible participation of transposable elements in nlDNA relocation is discussed.

Animals↗
PubMed2001

[Haplotype of Y-chromosomes in the Central Asia population].

The distribution of alleles and haplotypes of three diallellic Y-specific loci (YAP, DYF155S2, and Tat) in the populations of Kyrgyz, Uzbeks and Tajiks was analyzed. In Kyrgyzes and Uzbeks, a relatively high frequency of the DYF155S2 deletion (20 and 12.5%, respectively) and the C allele at the Tat locus (11.2 and 8.3%, respectively) were revealed. In the populations of southern Kyrgyzes and Uzbeks, two chromosomes carrying the YAP+ allele were detected. In both cases the YAP+ allele was found within the YAP+/DYF155S2+/TatT haplotype. The Tajik population was monomorphic in respect to the polymorphisms studied. The Tajiks demonstrated the presence of only the YAP-/DYF155S2+/TatT haplotype. This haplotype appeared to be most frequent in Kyrgyz (78.8%) and Uzbeks (83.3%). The question on the origin and the distribution of Y-chromosome variants in Eurasia are discussed.

Asia, Central↗
PubMed2000

[Pericentromeric and intercalating alpha-heterochromatin of polytene chromosomes of the malaria mosquito].

The properties of heterochromatin from polytene chromosomes of the malaria mosquito Anopheles messeae Fal. and A. atroparvus V. Tiel. were studied by various methods of differential staining and by hybridization in situ with two repetitive DNA sequences of Drosophila melanogaster. In malaria mosquito, the heterochromatin was heterogeneous. Two forms of alpha-heterochromatin were revealed: pericentromeric and intercalary heterochromatin, which is localized within the internal chromosome regions.

Animals↗
PubMed2000

[RAPD analysis of the flax (Linum usitatissimum L.) varieties and hybrids of various productivity].

Genetic polymorphism in varieties and hybrids of cultivated flax (Linum usitatissimum L.) has been investigated by RAPD-PCR. Analysis with 15 primers has revealed varietal specificity and hybrid inheritance of RAPD alleles. This allows genetic certification of the original varieties and their hybrids for breeding purposes. Polymorphic amplification products were obtained in RAPD analysis of DNA from two cultivated flax varieties with the use of 10-11 nucleotide primers.

Crosses, Genetic↗
PubMed1999

[Spatial organization of polytene chromosomes in ovarian trophocyte nuclei of the malaria mosquito Anopheles labranchiae Fall].

Spatial arrangement of polytene chromosomes in the ovarian trophocyte nuclei was studied in Anopheles labranchiae Fall. The system of chromosome attachment to the nuclear envelope in this species was found to differ from those in other species of the A. maculipennis complex. These results confirm that the spatial organization of nurse ovarian cell chromosomes is species-specific.

Animals↗
PubMed1997

[Attachment of polytene chromosomes to the nuclear envelope in ovarian pseudonurse cells in Drosophila melanogaster].

Certain aspects of the polytene chromosome attachment to the nuclear envelope (NE) of ovarian pseudonurse cells (PNC) in the mutant strains otu11 and fs(2) B of Drosophila melanogaster were studied. In contrast to salivary a local chromocenter and Rable-orientation of chromosomes were shown to be missing from the PNC nuclei. The pericentric regions were scattered in the nuclear space and were obliged to attach to the NE by specific loci of heterochromatin. These loci were assigned to the regions 20CD and 41, and the proximal regions 81 and 101 of the cytological map of secondary polytene chromosomes. Each of the loci, which was obliged to attach to the NE, had a specific morphology that was similar in the otu11 and fs(2)B strains. PNC were shown to resemble normal ovarian nurse cells of D. melanogaster in the position of the polytene chromosomes and their attachment to the NE.

Animals↗
PubMed1997

[Chromocenter organization in salivary glands of the malaria mosquito Anopheles messeae Fall].

The chromocenter organization and the relationship with the nuclear envelope were studied in Anopheles messeae Fall. malaria mosquito. The interchromosomal contacts within the chromocenter were shown to be formed by both alpha- and beta-heterochromatin. In the pericentric regions of all chromosomes and in highly repeated sequences localized mostly in alpha-heterochromatin, the incorporation of the moderate He-T repeat of D. melanogaster was also found. Each chromosome was shown to have an independent contact to the nuclear envelope via certain beta-heterochromatin loci. The morphology of the Y chromosome, which is also capable of forming ectopic contacts within the chromocenter boundaries, was studied.

Animals↗
PubMed1997

[Polymorphism of pericentromere heterochromatin of polytene chromosomes of ovarian trophocytes in natural populations of the malaria mosquito Anopheles messeae Fall].

Pericentric heterochromatin polymorphism in chromosome 2 of ovarian trophocytes was studied in three natural populations of the malaria mosquito Anopheles messeae Fall. It is shown that pericentric heterochromatin blocks occur in four different variants whose sizes are at the 1:2:3:4 ratio (single, double, triple, and quadruple blocks). Mosquitoes with homo- and heterozygous variants of these blocks were identified. By analyzing frequency distribution of different size variants, interpopulation differences in this parameter were revealed. Mosquitoes with double heterochromatin blocks prevailed in the southern population, whereas those with triple blocks were more abundant in the northern population.

Animals↗
PubMed1997

[Interspecies differences in the ovarian trophocyte precentromere heterochromatin structure and evolution of the malaria mosquito complex Anopheles maculipennis].

Studies on polytene chromosomes of ovarian trophocytes in malaria mosquitoes revealed significant variation of the structure of pericentromeric heterochromatin (PH). Variations in the number and size of pericentromeric alpha-heterochromatin blocks, puffing and interaction with the nuclear envelope of beta-heterochromatin, and the degree of asynapsis between pericentromeric regions of homologues were detected. Interspecific differences are characteristics of all three chromosomes of Anopheles maculipennis and seem to be directly associated with systemic mutations determining speciation.

Animals↗
PubMed1996

[The problem of systemic mutation].

The problems of the rearrangement of genome architecture during speciation are considered. The history of the problem of the role of systemic mutations in evolution is analyzed. The author's own phenomenological data on the spatial rearrangement of the chromosomal apparatus of germline tissue (that is regarded as systemic mutations) during the phylogeny of a number of dipterous insects are systematized. A concept on the essence of systemic mutations and their crucial role in saltatory transformation of genomes in the course of species evolution is advanced.

Animals↗
PubMed1996

[Organization of the primary polytene chromosome in the ovaries of 12 species of the "virilis" group of the genus Drosophila (Sophophora)].

Organization of chromosomes was analyzed in ovarian nurse cells in 12 species of the virilis group of Drosophila. A diffuse chromocenter containing a clearly detectable block of heterochromatin was shown to be characteristic of the phylogenetically ancestral species D. virilis and D. kanekoi. Similar organization of chromosomes was observed in two daughter species, D. lummei and D. falvomontana. The chromocenter disappeared either completely or partially in the phylads montana and virilis, respectively. These species exhibited separate chromosomes attached to a nuclear envelope and dispersed within the nucleus. Detected alterations in chromosome architecture confirm evolutionary trends previously revealed in species of the melanogaster subgroup.

Animals↗