The dissertation is focused on the analysis of the molecular organization,
evolution and use of 5S rDNA and CO1-CO2 genes as marker loci in the evaluation
of the genetic diversity of representatives of different groups of insects (Insecta).
The Introduction justifies the choice of topic and its relevance, formulates the
aim and tasks of the research, provides information on the publication of results in
scientific papers and on the approval of the dissertation at scientific forums. The
scientific novelty and practical value of the obtained results are characterized. The
introduction ends with information about the structure and scope of the dissertation.
The first section is a brief review of the literature highlighting existing problems and unresolved issues in insect taxonomy. The section also describes popular marker sequences used in modern molecular genetic studies to assess biodiversity (DNA barcoding) not only of insects but also of eukaryotes in general. Polymorphic loci of mitochondrial DNA are now considered one of the most informative DNA markers for insects. However, the use of only mitogenome regions has its limitations and disadvantages. Considering this, in addition to mtDNA sequences, it is necessary to use marker genes of the nuclear genome, which include ribosomal RNA genes, namely 5S rDNA. However, for insects, the potential of using 5S rDNA as a molecular marker still remains insufficiently studied. In view of this, the aim of the dissertation research was to analyze the variability of mitochondrial CO1-CO2 genes and nuclear 5S rDNA in different groups of insects and to evaluate the possibilities of using these genomic regions as molecular markers for barcoding and reconstruction of phylogenetic relationships in the taxa studied. To achieve the goal, the following tasks were set: 1. To amplify, clone and sequence the CO1-CO2 genes and 5S rDNA of representatives of different taxonomic groups of insects. 2. To search the nucleotide sequences database (GenBank) for the presence of СО1-СО2 and 5S rDNA sequences of the studied and closely related species. 3. To study the molecular organization of the genomic regions selected for
analysis, and to evaluate their polymorphism. 4. Based on the data obtained, draw a conclusion about the possibility of using CO1-СО2 and 5S rDNA regions in the assessment of the genetic diversity of insects. The object of research is genetic polymorphism and evolution of eukaryotic genomes. The subject is 5S ribosomal DNA and genes of cytochrome oxidase СО1 and СО2. Research methods: in the process of preparing the dissertation, modern laboratory research methods were used, which are mentioned in the second chapter, in particular: isolation of genomic and plasmid DNA, DNA quantification, polymerase chain reaction (PCR), electrophoretic analysis, creation of recombinant constructs and cloning of DNA fragments, DNA sequencing. Bioinformatics
methods were also used: analysis of DNA sequences, screening of genomic databases, analysis of whole genome archives, alignment of DNA sequences and construction of phylogenetic dendrograms. The following statements reveal the scientific novelty of dissertation research based on the results obtained (third section): 1. For the first time, CO1-CO2 genes and 5S rDNA repeated regions were cloned and sequenced for different subspecies of the honey bee Apis mellifera, pest butterflies of the Drepanidae family, and fruit flies of the Tephritidae family. 2. The chromosomal localization of 5S rDNA clusters in honeybees, butterflies and fruit flies was described for the first time, and a new type of dispersed organization of 5S rDNA in butterfly genomes was discovered. 3. The molecular organization, polymorphism, and nature of variability of 5S rDNA in the studied species are described and analyzed in detail. 4. Significant differences in the molecular organization and rate of evolution of 5S rDNA in different groups of insects were revealed. 5. A comparative assessment of the possibilities of using various molecular markers, i.e., 5S rDNA and CO1-CO2 genes for barcoding and insect phylogeny reconstruction was carried out. The thesis is presented on 158 pages of typewritten text. The work contains 11 tables and 26 figures. The references consist of 188 literature sources.
