[Databases as instruments for analysis of large-scale data sets on interactions between molecular biological objects].

We have surveyed the most well-known and accessible informational resources, consolidating data on interactions of molecular biological objects. Three main criteria are discussed: quality (coverage and reliability) of the information present, ability to analyze experimental data, and ease of results visualization. Several algorithms of data analysis, base on various types of resources, and statistics for its evaluation are named.

[Mitochondrial genome variation in domesticated sable (Martes zibellina)].

The first comparison of mitochondrial variations in sables from captive and natural populations of the Urals, Central Siberia, Yakutia, Kamchatka, and Japan has been performed. The object of comparative analysis was a 427-bp 5' fragment of the mitochondrial control region, including the D-loop. Two main haplogroups of the sable mitochondrial genome have been found, which provides new data for reconstruction of the spread of the sable over its current range. Asymmetry of the haplotype abundances in the captive populations of sables has been detected. The mitochondrial haplotypes characteristic of sable breeds have been identified. The possible role of the frequent mitochondrial haplotypes of the captive population in the sable adaptation to the conditions of captivity is discussed.

[Dynamics of mitochondrial polymorphism in a natural population of Drosophila littoralis].

During seven years, we observed stable mtDNA polymorphism in a local population of Drosophila littoralis. Using RFLP, a number of mitochondrial haplotypes were revealed, two of which were the core and in condition of stable equilibrium. To explain the absence of fixation of one haplotype, we checked a hypothesis that the D. littoralis population had a complex structure, being subdivided into several partially isolated races existing on the same territory. Analysis of highly hypervariable nuclear sequence of retrotransposons Tv1 showed positive correlation of the mitochondrial haplotype with a particular allelic form of Tv1. This supports the proposal that the D. littoralis natural population forms the population system consisting of genetically differentiated races.

[Variation of 3'-terminal fragment of 16S rRNA gene in closely related species of Drosophila virilis group].

Primary sequence of 3-terminal fragment of the mitochondrial 16S rRNA gene has been determined in 12 Drosophila species of the virilis group. The functionally important elements in secondary structure of the RNA product were defined. The region corresponding to the peptidyltransferase center has been localized. Variation of the 3'-terminal region of 16S rRNA gene has been described in 12 species of the virilis group. Phylogeny of the Drosophila virilis species group is discussed.

[Mitochondrial DNA polymorphism in the natural populations of the Drosophila virilis species group]. / Polimorfizm mitokhondrial'noi DNK prirodnykh populiatsii drozofil gruppy virilis.

Restriction fragment length polymorphism (RFLP) analysis has been used to evaluate mitochondrial DNA (mtDNA) variation in 12 sibling species forming the Drosophila virilis species group. The variation thresholds corresponding to the interspecific and interstrain levels have been determined. The results indicate that interspecific hybridization has significantly contributed to the evolutionary history of the virilis species group.

[Variation of the mitochondrial genome in the evolution of Drosophila]. / Izmenchivost' mitokhondrial'nogo genoma v évoliutsii Drosophila.

The evidence on mitochondrial genome variation and its role in evolution of the genus Drosophila are reviewed. The mitochondrial genome is represented by a circular double-stranded DNA molecule 16 to 19 kb in length. The genome contains no introns involved in recombination. The entire mitochondrial genome can be arbitrarily divided into three parts: (1) protein-coding genes; (2) genes encoding rRNA and tRNA; and (3) the noncoding regulatory region (A + T region). The selective importance of mutations within different mtDNA regions is therefore unequal. In Drosophila, the content of the A + T pairs in mtDNA is extremely low and a pattern of nucleotide substitution is characterized by a low transition/transversion ratio (and a low threshold of mutation saturation). The deletions and duplications are of common occurrence in the mitochondrial genome. However, this genome lacks such characteristic for the nuclear genome aberrations as the inversions and transpositions. The phenomena of introgression and heteroplasmy provide an opportunity to study the adaptive role of the mitochondrial genome and its role in speciation. Analysis of evidence concerning mtDNA variation in different species of the genus Drosophila made it possible to ascertain data on phylogenetic relationships among species obtained by studying nuclear genome variation. In some species, mtDNA variation may serve as a reliable marker for population differentiation within a species, although evidence on the population dynamics of the mtDNA variation is very scarce.