Svetlana Galkina

St Petersburg University | SPBU · Department of Genetics and Biotechnology

Drosophila melanogaster is the oldest classic model object in developmental genetics. It may seem that various structures of the fruit fly at all developmental stages have been well studied and described. However, recently we have shown that some specialized structures of the D. melanogaster eggshell contain an amyloid fibril network. Here, we demo...

Subterranean rodents represent an interesting model system for molecular ecologists. Their lifestyle is associated with fragmented environments, limited dispersal ability, and low fecundity. These characteristics all are expected to increase inter-and intrapopulation differentiation and reduce intra-population genetic diversity, yet the published e...

Background: Ellobius talpinus is a subterranean rodent representing an attractive model in population ecology studies due to its highly special lifestyle and sociality. In such studies, mitochondrial DNA (mtDNA) is widely used. However, if nuclear copies of mtDNA, aka NUMTs, are present, they may co-amplify with the target mtDNA fragment, generatin...

Citation: Dyomin, A.; Galkina, S.; Ilina, A.; Gaginskaya, E. Single Copies of the 5S rRNA Inserted into 45S rDNA Intergenic Spacers in the Genomes of Nototheniidae (Perciformes, Actinopterygii). Int. J. Mol. Sci. 2023, 24, 7376. https:// Abstract: In the vast majority of Animalia genomes, the 5S rRNA gene repeats are located on chromosomes outside...

The chicken continues to hold its position as a leading model organism within many areas of research, as well as a being major source of protein for human consumption. The First Report on Chicken Genes and Chromosomes [Schmid et al., 2000], which was published in 2000, was the brainchild of the late, and sadly missed, Prof Michael Schmid of the Uni...

It is believed that the nucleolus organizer region (NOR) in the ovary of adult birds is inactivated at all stages of oocyte growth. However, in the ovary of juvenile chicken (Gallus g. domesticus) one or two nucleoli were observed in 50% of early diplotene oocytes. These nucleoli were functioning up to the lampbrush stage. It was assumed that diplo...

Tandemly repeated DNAs form heterochromatic regions of chromosomes, including the vital centromeric chromatin. Despite the progress in new genomic technologies, tandem repeats remain poorly deciphered and need targeted analysis in the species of interest. The Japanese quail is one of the highest-producing poultry species as well as a model organism...

Tandem repetitive sequences represent a significant part of many genomes but remain poorly characterized due to various methodological difficulties. Here, we describe the tandem repeat composition in the genome of zebra finch, Taeniopygia guttata , a species that has long served as an animal model, primarily in neurobiology and comparative genomics...

Proteins that normally function in amyloid form are found in bacteria, yeast, plants and vertebrates, including humans. In particular, amyloid fibrils and amyloid-like structures are described in the germ cells of various organisms. Recently we showed that in chicken oocytes there are some nuclear structures that are stained by the amyloid-specific...

In most eukaryotic genomes, tandemly repeated copies of 5S rRNA genes are clustered outside the nucleolus organizer region (NOR), which normally encodes three other major rRNAs: 18S, 5.8S, and 28S. Our analysis of turtle rDNA sequences has revealed a 5S rDNA insertion into the NOR intergenic spacer in antisense orientation. The insertion (hereafter...

Heteromorphic W and Y sex chromosomes often experience gene loss and heterochromatinization, which is frequently viewed as their “degeneration”. However, the evolutionary trajectories of the heterochromosomes are in fact more complex since they may not only lose but also acquire new sequences. Previously, we found that the heterochromatic W chromos...

The review is focused on the development of ideas about the role of one of the most mysterious phenomena of developmental biology, i.e., the transformation of chromosomes into the so-called lampbrush chromosomes (LBCs). Eukaryotic chromosomes in the LBC phase are characterized by a low level of condensation and discrete structure formed by numerous...

The features of rDNA amplification have been studied in oocytes of the red-eared slider Trachemys scripta using a number of specific histochemical and cytomolecular methods. A single nucleolus in early diplotene oocytes is associated with the nucleolus organizer region (NOR). With oocyte growth, the number of nucleoli increases dramatically and rea...

Primary cell lines of the red-eared slider were established from somatic slider tissues cultivated in appropriate medium for a certain period. Exponential cell growth started after 2 weeks of continuous cultivating. The cells were of various morphology resembling keratinocytes, fibroblasts, and melanocytes, some of them gathered to form dense congl...

We conducted a cytological search for amyloid structures in female reproductive cells of Gallus gallus domesticus and Drosophila melanogaster. We have shown that the amyloid-specific dye, Thioflavin S, but not Congo red, stains some cytoplasmic and even nuclear structures in chicken ovaries. In fruit fly eggs both Thioflavin S and Congo red specifi...

Background: Ribosomal DNA (rDNA) repeats are situated in the nucleolus organizer regions (NOR) of chromosomes and transcribed into rRNA for ribosome biogenesis. Thus, they are an essential component of eukaryotic genomes. rDNA repeat units consist of rRNA gene clusters that are transcribed into single pre-rRNA molecules, each separated by intergen...

Lampbrush chromosome spread of Eremias velox. A: Phase contrast. B: FISH with the W-specific probe. DAPI (blue), W-specific probe (red). Arrowhead indicates sex bivalent. Scale bars: 30 μm.

Reptiles are good objects for studying the evolution of sex determination, since they have different sex determination systems in different lineages. Lacertid lizards have been long-known for possessing ZZ/ZW type sex chromosomes. However, due to morphological uniformity of lacertid chromosomes, the Z chromosome has been only putatively cytological...

Significance We discovered that contrary to other bird species and most other animals, all examined songbird lineages contain a different number of chromosomes in the somatic and germline genomes. Their germ cells have an additional germline-restricted chromosome (GRC). GRCs contain highly duplicated genetic material represented by repetitive eleme...

The genome of flying birds, the smallest among amniotes, reflects overweight of the extensive DNA loss over the unrestricted proliferation of selfish genetic elements, resulted in a shortage of repeated sequences and lack of B-chromosomes. The only exception of this rule has been described in zebra finch, which possesses a large germ-line restricte...

In memory of Ingemar Gustavsson 23 rd International Colloquium on Animal Cytogenetics and Genomics (23 ICACG) took place in June 9–12, 2018 in Saint-Petersburg, Russia. Organized biennially, the Colloquium runs from 1970. From its very start this meeting is associated with the name of Ingemar Gustavsson to whom we dedicated the Colloquium 2018. The...

The search for novel pathological and functional amyloids represents one of the most important tasks of contemporary biomedicine. Formation of pathological amyloid fibrils in the aging brain causes incurable neurodegenerative disorders such as Alzheimer's, Parkinson's Huntington's diseases. At the same time, a set of amyloids regulates vital proces...

The content of repetitive DNA in avian genomes is considerably less than in other investigated vertebrates. The first descriptions of tandem repeats were based on the results of routine biochemical and molecular biological experiments. Both satellite DNA and interspersed repetitive elements were annotated using library-based approach and de novo re...

Lampbrush chromosomes represent transcriptionally active chromosomes that exist during the extended diplotene phase in the growing ovarian eggs of many vertebrate animals, except therian mammals. They are excellent for studying chromosome structure and aspects of RNA transcription. Because of their giant size they allow a great increase in the reso...

Elena Gaginskaya is an outstanding scientist, doctor of biological sciences, professor, international expert, creator of the first core facility at St. Petersburg State University, and the founder of the Lampbrushology Scientific School. She celebrates her 85th birthday this year. Students, colleagues and friends congratulate Elena with all their h...

Analyzing the complex origin of various chicken breeds and populations is fundamental for understanding, preserving, and exploiting their genetic diversity. Here, we aim to assess the different contributions to mitochondrial genetic diversity of the Pavlov chicken breed. The mitochondrial DNA control region (D-loop 1231/1232 b.p. in length) in 37 c...

Lampbrush chromosomes are giant, transcriptionally active, meiotic chromosomes found in oocytes of all vertebrates with the exception of mammals. Lampbrush chromosomes offer a convenient tool for cytogenetic mapping and, in particular, have been instrumental in mapping genes and linkage groups on chicken (GGA) chromosomes. Whereas cytogenetic maps...

Sequences of ribosomal internal transcribed spacers (ITSs) are of great importance to molecular phylogenetics and DNA barcoding, but remain unstudied in some large taxa of Deuterostomia. We have analyzed complete ITS1 and ITS2 sequences in 62 species from 16 Deuterostomia classes, with ITS sequences in 24 species from 11 classes initially obtained...

The amphipod Gmelinoides fasciatus from Lake Baikal is an example of a species being introduced into a number of water bodies in Russia, including the water system of North-west Russia, to expand food reserves of commercial fish. The interest in this crustacean has been attributed to its successful adaptation and expanding habitat area in the regio...

Journal of Science and Technology in Lighting, v.41, pp.52-56, (2017) --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The wo...

The genes of rRNA in the nucleolar organizer region (NOR) are inactivated in the oocytes of adult birds despite the functioning of lampbrush chromosomes. The nucleolus is not formed during all stages of the oocyte development. On the other hand, two morphological forms of oocytes differing by the presence of nucleolus in the germinal vesicle are de...

Sequences of ribosomal internal transcribed spacers (ITSs) are of great importance to molecular phylogenetics and DNA barcoding, but remain unstudied in some large taxa of Deuterostomia. We have analyzed complete ITS1 and ITS2 sequences in 62 species from 16 Deuterostomia classes, with ITSs sequences in 24 species from 11 classes initially obtained...

Preserving family bonds in birds during seasonal migration is uncommon. Among passerine birds, migration of family groups has not yet been genetically confirmed. Here, we tested whether long-tailed tits migrate in family groups in autumn. We studied two partially migrating populations of the nominate subspecies Aegithalos caudatus caudatus (in Nort...

Despite long-term exploration into ribosomal RNA gene functioning during the oogenesis of various organisms, many intriguing problems remain unsolved. In this review, we describe nucleolus organizer region (NOR) activity in avian oocytes. Whereas oocytes from an adult avian ovary never reveal the formation of the nucleolus in the germinal vesicle (...

To elucidate geographical and historical aspects of chicken dispersal across Eastern Europe, we analysed the complete mitochondrial DNA D-loop sequence of 86 representatives from chicken breeds traditionally raised in the territory of the East European Plain (Orloff, Pavlov, Russian White, Yurlov Crower, Uzbek Game and Naked Neck). From the 1231–12...

After birds diverged from mammals, different ancestral autosomes evolved into sex chromosomes in each lineage. In birds, females are ZW and males are ZZ, but in mammals females are XX and males are XY. We sequenced the chicken W chromosome, compared its gene content with our reconstruction of the ancestral autosomes, and followed the evolutionary t...

Ribosomal RNA (rRNA) genes, whose activity results in nucleolus formation, constitute an extremely important part of genome. Despite the extensive exploration into avian genomes, no complete description of avian rRNA gene primary structure has been offered so far. We publish a complete chicken rRNA gene cluster sequence here, including 5’ETS (1836...

18S rRNA gene sequence boundaries resulted from a multiple sequence alignment. Indications are the same as in S1 Fig. (TIF)

Chicken 5.8S rRNA gene sequence boundaries resulted from a multiple sequence alignment. Indications are the same as in S1 Fig. (TIF)

Chicken ITS2 sequence boundaries resulted from a multiple sequence alignment. Indications are the same as in S1 Fig. (TIF)

Chicken 28S rRNA gene sequence boundaries resulted from a multiple sequence alignment. Indications are the same as in S1 Fig. (TIF)

Chicken 5’ETS sequence boundaries resulted from a multiple sequence alignment. Black frames outline the elements of the ribosomal cluster. Cluster members are schematically indicated by colored boxes. Asterisk–chicken pre-rRNA transcription initiation site. Arrow–transcription direction. Double slashes schematically point the hidden area of alignme...

Raw read assembly verification using WGS contigs and annotated sequences. (PDF)

De novo and re-assembled rRNA gene cluster sequence alignment. (PDF)

Chicken ITS1 sequence boundaries resulted from a multiple sequence alignment. Indications are the same as in S1 Fig. (TIF)

Chicken ITS2 ssDNA secondary structures under the conditions of T = 60°C, [K+] = 50 mM. (PDF)

Chicken 3’ETS sequence boundaries resulted from a multiple sequence alignment. Indications are the same as in S1 Fig. (TIF)

Multiple alignment matrix for chicken rRNA gene cluster boundaries search using annotated fragments of ribosomal clusters of Homo sapiens, Rattus norvegicus, Mus musculus, Xenopus laevis and Crocodylus porosus. (PDF)

Chicken ITS1 ssDNA secondary structures under the conditions of T = 60°C, [K+] = 50 mM. (PDF)

In this paper, we analyzed the distribution and the transcriptional activity of different repetitive elements in the sex chromosomes of chicken at the lampbrush stage. Based on these results, we suggest participation of interspersed repeats in the maintenance evolutionarily significant level of variability of heteromorphic sex chromosomes in birds....

Background Repeated clusters of ribosomal genes whose activity results in the nucleolus formation are extremely important in multicellular organism genome. Despite the extensive exploration into vertebrate genomes, in many model objects the ribosomal cluster structure is still underinvestigated. So far, complete description for primary structure of...

Irradiation of various types of microfungi spores by vacuum ultraviolet radiation (VUV) (λ = 172 nm, 2 mW/cm2) was carried out in this work. It was found, that the VUV radiation leads to inactivation of spores in the dose range 10-240 mJ/cm2, depending on the fungal species. Shadowing effect of overlapping layers of spores was observed. Protective...

Elucidation of the complex origin of various chicken breeds and populations is of essential importance for understanding, preserving and exploiting their genetic diversity. Here, we aim to assess different contributions to mitochondrial genetic diversity of Pavlov chicken breed. Mitochondrial DNA control region (D-loop of 1231/1232 b. p. length) in...

Abstract Aims: Fluorescent in situ hybridization (FISH), the routine technique of molecular cytogenetics, is widely used to detect and localize the presence of specific nucleic acids sequences in chromosomes, cell nucleus space, cells and tissue samples through the use of highly complementary probes to targets sequence. Expansion of FISH method ap...

Analysis of chiasma distribution within the 0–23-Mb region of chicken LBC3. a A fragment of chicken LBC3 cytological map with a histogram of chiasma distribution along the bivalent. Chiasmata were defined as crisscrosses of homologous chromosomes in a bivalent. The total number of analyzed bivalents was 50. Chromomeres and lateral loops comprising...

Chicken (Gallus gallus domesticus, GGA) and Japanese quail (Coturnix coturnix japonica, CCO) karyotypes are very similar. They have identical chromosome number (2n = 78) and show a high degree of synteny. Centromere positions on the majority of orthologous chromosomes are different in these two species. To explore the nature of this divergence, we...

Markers used in this study. File format: Excel