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A F Smirnov

Publications and source records attributed to A F Smirnov.

At least 19 recordsLinked to original sources
PubMed2005

Chromosomal localization of seven HSA3q13-->q23 NotI linking clones on chicken microchromosomes: orthology of GGA14 and GGA15 to a gene-rich region of HSA3.

Double-color fluorescence in situ hybridization was performed on chicken chromosomes using seven unique clones from the human chromosome 3-specific NotI linking libraries. Six of them (NL1-097, NL2-092, NL2-230, NLM-007, NLM-118, and NLM-196) were located on the same chicken microchromosome and NL1-290 on another. Two chicken microchromosome GGA15-specific BAC clones, JE024F14 containing the IGVPS gene and JE020G17 containing the ALDH1A1 gene, were cytogenetically mapped to the same microchromosome that carried the six NotI linking clones, allowing identification of this chromosome as GGA15. Two GGA14-specific clones, JE027C23 and JE014E08 containing the HBA gene cluster, were co-localized on the same microchromosome as NL1-290, suggesting that this chromosome was GGA14. The results indicated that the human chromosomal region HSA3q13-->q23 is likely to be orthologous to GGA15 and GGA14. The breakpoint of evolutionary conservation of human and chicken chromosomes was detected on HSA3q13.3-->q23 between NL1-290, on the one hand, and six other NotI clones, on the other hand. Considering the available chicken-human comparative mapping data, another breakpoint appears to exist between the above NotI loci and four other genes, TFRC, EIF4A2, SKIL and DHX36 located on HSA3q24-->qter and GGA9. Based on human sequences within the NotI clones, localization of the six new chicken coding sequences orthologous to the human/rodent genes was suggested to be on GGA15 and one on GGA14. Microchromosomal location of seven NotI clones from the HSA3q21 T-band region can be considered as evidence in support of our hypothesis about the functional analogy of mammalian T-bands and avian microchromosomes.

Animals↗
PubMed2005

[Libraries of large-insert genomic clones as a tool for molecular cytogenetic analysis of avian genome].

Integration of molecular and cytegenetic levels of investigation results in complex understanding of structural and functional genome organization. Gridded libraries of large-insert genomic clones represent a powerful tool of the genome analysis. Their utilization provides coordination of data on molecular organization of nucleic acids with cytogenetic data on the chromosome structure. These libraries played an important role in sequencing of genomes of human, mouse, and other organisms as an instrument linking molecular biological and cytogenetic data via construction of contigs and their localization on the chromosomes. They also enabled analysis of orthology between the mammalian genomes. The existing avian libraries fit molecular cytogenetic analysis of the class Aves genome, and can be successfully used for the isolation and characterization of large genomic fragments. This provides utilization of these libraries not only for the chromosome mapping, but also for positional cloning and search for candidate genes for quantitative traits.

Animals↗
PubMed2003

[Comparative compositional mapping of chicken and quail chromosomes].

The distribution of various isochore families on mitotic chromosomes of domestic chicken and Japanese quail was studied by the method of fluorescence in situ DNA--DNA hybridization (FISH). DNA of various isochore families was shown to be distributed irregularly and similarly on chromosomes of domestic chicken and Japanese quail. The GC-rich isochore families (H2, H3, and H4) hybridized mainly to microchromosomes and a majority of macrochromosome telomeric regions. In chicken, an intense fluorescence was also in a structural heterochromatin region of the Z chromosome long arm. In some regions of the quail macrochromosome arms, hybridization was also with isochore families H3 and H4. On macrochromosomes of both species, the pattern of hybridization with isochores of the H2 and H3 families resembled R-banding. The light isochores (L1 and L2 families) are mostly detected within macrochromosome internal regions corresponding to G bands, whereas microchromosomes lack light isochores. Although mammalian and avian karyotypes differ significantly in organization, the isochore distribution in genomes of these two lineages of the warm-blooded animals is similar in principle. On macrochromosomes of the two avian species studied, a pattern of isochore distribution resembled that of mammalian chromosomes. The main specific feature of the avian genome, a great number of microchromosomes (about 30% of the genome), determines a compositional specialization of the latter. This suggests the existence of not only structural but also functional compartmentalization of the avian genome.

Animals↗
PubMed2003

[Localization of cohesin complexes of polytene chromosomes of Drosophila melanogaster located on interbands].

The distribution of cohesin complex in polytene chromosomes of Drosophila melanogaster was studied. Cohesin is a complicated protein complex which is regulated by the DRAD21 subunit. Using immunostaining for DRAD21p, the cohesins were shown to be preferentially located in the interband regions. This specificity was not characteristic for puffs, where uniform staining was observed. The presence of a few brightly fluorescent regions (five to ten per chromosome arm) enriched with cohesin complexes was shown. Some of these regions had permanent location, and the others, variable location. No antibody binding was detected in the chromocenter. Immunostaining of interphase nuclei of neuroblasts revealed large cohesin formations. On the polytene chromosomes of D. melanogaster, the Drad21 gene was mapped to the chromocentric region (81) of the L arm of chromosome 3.

Animals↗
PubMed2001

Compositional mapping of chicken chromosomes and identification of the gene-richest regions.

'Compositional chromosomal mapping', namely the assessment of the GC level of chromosomal bands, led to the identification, in the human chromosomes, of the GC-richest H3+ bands and of the GC-poorest L1+ bands, which were so called on the basis of the isochore family predominantly present in the bands. The isochore organization of the avian genome is very similar to those of most mammals, the only difference being the presence of an additional, GC-richest, H4 isochore family. In contrast, the avian karyotypes are very different from those of mammals, being characterized, in most species, by few macrochromosomes and by a large number of microchromosomes. The 'compositional mapping' of chicken mitotic and meiotic chromosomes by in-situ hybridization of isochore families showed that the chicken GC-richest isochores are localized not only on a large number of microchromosomes but also on almost all telomeric bands of macrochromosomes. On the other hand, the GC-poorest isochores are generally localized on the internal regions of macrochromosomes and are almost absent in microchromosomes. Thus, the distinct localization of the GC-richest and the GC-poorest bands observed on human chromosomes appears to be a general feature of chromosomes from warm-blooded vertebrates.

Animals↗
PubMed2001

[Destabilizing effect of chicken selection using the functional adrenal reserves criteria].

Chicken lines produced by divergent selection for the functional adrenal reserves showed significant between-line differences in the content of corticosterone and other hormones (thyroxin, progesterone), as well as in body weight, early maturation, and egg yield. DNA fingerprinting with the pGB725 probe revealed molecular changes in genomic DNA of the chicken lines subjected to plus and minus selection. The genetic distances between the original population and the selected chicken lines, which were estimated from the molecular hybridization patterns, reflected the history of breeding. Analysis of mixed DNA from several individuals of each line revealed specific hybridization bands that could serve as DNA markers during selection for the high and low corticosterone levels in blood.

Adrenal Glands↗
PubMed2000

[Modeling heterochromatin regions in transgenic mice].

Transgenic mice carrying bovine satellite DNA IV were obtained. The size of the transgene integrated into the mouse genome was approximately 390 kb (about 100 transgene copies) as determined by a semiquantitative PCR. Restriction analysis with isoschizomeric restrictases HpaII and MspI, showed that the alien DNA was methylated. In the genome of a transgenic founder male, two integration sites for satellite DNA IV were revealed by in situ hybridization and in situ PCR. These sites are situated on two different chromosomes: in pericentromeric heterochromatin and within a chromosomal arm. In transgenic mice, de novo formation of heterochromatin regions (C-block and the CMA3 disk within the centromeric heterochromatin of another chromosome) was revealed by C-banding and staining with chromomycin A3. This formation is not characteristic of mice, because their chromosomes normally contain no interstitial C-blocks or sequences intensely stained by chromomycin A3.

Animals↗
PubMed1999

[The detection of transgenic animals using a polymerase chain reaction in situ].

The technique for detecting both foreign and host specific DNA sequences inside nuclei and chromosomes of single cells of transgenic mice with the help of polymerase chain reaction (PCR) in situ is described. The mouse preimplantation and postimplantation embryonic and adult cells were studied. The methodology is described in detail with particular attention to the optimization of composition of reaction mixture, kind of fixation and preliminary denaturation of target DNA. The reaction takes only several hours and needs no sophisticated equipment.

Animals↗
PubMed1999

[Molecular genetic analysis of hobo mobile genetic element polymorphism in the genome of Drosophila melanogaster line subjected to long-term selection].

The distribution of mobile genetic element hobo was examined in Drosophila melanogaster lines HA (high male mating activity) and LA (low male mating activity) before and after their isogenization using Southern blot hybridization. The probe containing a full-size hobo copy was shown to produce polymorphic multilocus hybridization with chromosomal DNA. The polymorphism was line-specific. A comparison of hybridization patterns in isogenic and original lines showed that isogenization in dysgenic crosses resulted in the appearance of additional hobo localization sites in LA but not in HA. The hobo destabilization in the LA genome correlated with genetic instability and the ability to induce H-E hybrid dysgenesis. The results obtained are discussed in relation to the possible role of hobo in inducing genetic variability in lines with low male mating activity, which may counteract deleterious consequences of inbreeding and selection in the negative direction.

Animals↗
PubMed1998

[Karyotypic instability of peripheral blood lymphocytes in cows Bos taurus L. infected with bovine leukemia virus].

Chromosomal aberrations (CAs), sister-chromatid exchanges (SCEs), aneuploidy and proliferative potential (PP) were investigated in peripheral blood lymphocytes of healthy cows (control group-C), BLV-(bovine leucosis virus)-infected cattle without hematological abnormalities (RID--seropositive group (I) and affected with leucaemia (lymphocytosis (LC), lymphoma (L)). Nonrandom chromosomal (marker) aberrations were not found in the cow group at stage LC. The levels of aneuploidy and SCEs increased in the cow group at stage L compared to the cow group at stage I. Polyploidy: C--1.9 +/- 0.28, I--3.5 +/- 0.22, LC--6.1 +/- 0.82, L--10.5 +/- 0.51 (P < 0.01). Hypoploidy (2n = 58): C--3.0 +/- 0.17, I--54 +/- 0.71, LC--12.1 +/- 0.72, L--14.0 +/- 0.65 (P < 0.01). SCEs: C--3.8 +/- 0.26, I--5.4 +/- 0.15, LC--7.2 +/- 0.16, L--9.7 +/- 0.26 (P < 0.01). There are no differences in CAs rates and PP between groups of cows at all the observed stages of leucaemic process. The obtained results are discussed in terms of cytogenetic aspects of leucaemic process in cows.

Animals↗
PubMed1998

[Distribution of T-bands and telomeric (TTAGGG)n nucleotide repeats on chromosomes of Bos taurus].

Distribution of T-bands on mitotic chromosomes of Bos taurus was studied. Association of T-bands with telomeres and enrichment of T-bands with genes, with a known localization is described. After THA-banding on the chromosomes of cattle, telomeric and pericentromeric regions of all autosomes showed bright fluorescence. The exception was for chromosome 7, which did not have telomeric T-bands. Interstitial T-bands were detected only on chromosomes 7, 16, and Y (7q13, 7q15, 7q22, 7q24, 16q21, and Yp12). A total proportion of centromeric, telomeric, and interstitial T-bands was 11.19, 9.97, and 2.02% of the length of the haploid chromosome set, respectively. By means of fluorescent in situ hybridization (FISH), the presence of the telomeric repeat (TTAGGG)n was shown not only in telomeric regions of all autosome, but also in all pericentromeric regions. The obtained data are indicative of the specificity of T-banding on the chromosomes of Bos taurus.

Animals↗
PubMed1997

[Heterochromatin and euchromatin regions in the chromosomes of various representatives of the subfamily Bovinae].

Heterochromatin distribution was studied in three species of subfamily Bovinae: bison (Bison bison), European bison (Bison bonasus), and gayal (Bos frontalis). In all of the studied species, C- and CMA3-banding and in situ hybridization with satellite DNAII (satDNAII) revealed the conservative distribution of heterochromatic regions in autosomes; sex chromosomes did not contain the classical constitutive heterochromatin. The Y chromosome was the most variable element of the karyotypes of both bison species and the gayal. A mechanism for formation of the acrocentric Y chromosome in B. bison was suggested. This hypothetical mechanism included breakage of the p arm at the telomeric region and subsequent translocation and inversion. The map of B. bison chromosomes (491 bands per haploid set) is presented. The data obtained are discussed in terms of speciation and the evolution of Bovinae karyotypes.

Animals↗