As assemblies of genomes of new species with varying degrees of relationship appear, it becomes obvious that structural rearrangements of the genome, such as inversions, translocations, and transposon movements, are an essential and often the main source of evolutionary variation. In this regard, the following questions arise. How conserved are the regulatory regions of genes? Do they have a common evolutionary origin? And how and at what rate is the functional activity of genes restored during structural changes in the promoter region? In this article, we analyze the evolutionary history of the formation of the regulatory region of the ras85D gene in different lineages of the genus Drosophila, as well as the participation of mobile elements in structural rearrangements and in the replacement of specific areas of the promoter region with those of independent evolutionary origin. In the process, we substantiate hypotheses about the selection of promoter elements from a number of frequently repeated motifs with different degrees of degeneracy in the ancestral sequence, as well as about the restoration of the minimum required set of regulatory sequences using a conversion mechanism or similar.

In the females of the viviparous lizard Zootoca vivipara (Lichtenstein, 1823) (family Lacertidae) from Northwest Russia (2n = 35: 32A (acrocentric autosomes) + Z(1)Z(2)W sex chromosomes), the ovarian lumen germinal vesicles (oocytes), as well as germinal lamina cells, were examined. Chromosome preparations were obtained using the direct method and the method of total oocyte nuclei spreading developed by Dresser and Moses. Chromosome preparations were stained with Giemsa; for visualization of synaptonemal complexes (SCs), total preparations of oocyte nuclei were stained with silver nitrate and DAPI. It was demonstrated that, during oogenesis in the female, primary follicles enter the early stages of the meiotic prophase I (stages from leptotene to diplotene, lampbrush chromosomes are formed). Here, for the first time, total oocyte spreads were obtained and studied. On the basis of light microscopic analysis of the oocyte SCs and taking into account their length in a female with 2n = 35, the SC karyotype is presented, consisting of 19 SC elements, among which 16 SC autosomal bivalents are distinguished. The remaining three SC elements, according to the authors, can be univalents of Z(1)Z(2)W sex chromosomes or one WZ(1) bivalent and Z(2) and Bchromosome univalents. As in the SC karyotype of Z. vivipara males, in a female, specific features in the morphology of SC elements of chromosomes 5 and 6 were observed.

The results of analysis of the frequencies of t -alleles and heterozygous +/ t individuals of house mice of different subspecies ( musculus, bactrianus, tataricus, wagneri , and gansuensis ) are presented for the natural populations inhabiting eight cities and five regions of Russia and adjacent countries of Eastern Europe and Asia. It is shown that the frequencies of t-alleles are 0.18 ± 0.03 in small samples (1–30 individuals) and 0.09 ± 0.06 in medium-sized samples (31–60 individuals). The factors that reduce the frequencies of t -alleles in natural populations and the mechanisms that prevent invasion and fixation of t -mutant alleles in the Mus musculus genome are discussed.

Ras genes were first identified in the 1960s as transforming oncogenes that caused tumors in rats infected with Harvey and Kirsten sarcoma viruses (Ha-ras and Ki-ras oncogenes, accordingly). Subsequently, transforming ras genes were found in human cancer cells. Further investigations of neuroblastoma cells resulted in the finding of the third ras gene in the human, which was called N-ras. Ras gene products play an important role in the processes of cellular proliferation and differentiation and are controlled by receptor tyrosine kinases. Using drosophila as a model object allowed us to perform a successful genetic analysis while studying the functions of ras genes. Three polytene chromosome bands were detected in D. melanogaster with the help of the v-Ha ras sampling. According to Bridges’ map, all three bands (Dras1, Dras2, Dras3) were mapped to regions 85D, 64B, and 62B of chromosome 3. Among them, only Dras1 has a common origin with ras genes of mammals. Although there are numerous investigations of the role played by ras genes in the development of insects, this problem is still not fully understood. The importance of ras gene variations in the course of the evolutionary process has been insufficiently studied as well. Currently, Ras target proteins are actively identified, their signal pathways, as well as effects of influencing these pathways in the drosophila tissues, are studied in the cells of yeast and mammals. The main functions of Ras protein is in the signaling pathways controlling mutations during drosophila’s morphogenesis and the connections of ras gene with phenotypic symptoms of tumors.

Drasl gene was mapped by in situ hybridization to polytene chromosomes of several sibling species of the Drosophila virilis group and hybrids between them. A 1037 bp fragment of the Drasl gene of the D. virilis genome was used as a probe. The gene sequence is localized to the region of the disk 25 A-B on the chromosome 2 of the polytene chromosome map of D. virilis.

Целью работы является проверка гипотезы, согласно которой несоответствия в оценке времени расхождения и топологии видов Drosophila kanekoi, D. ezoana и D. littoralis обусловлены разной скоростью накопления замен в различных последовательностях ДНК, используемых для анализа, и эволюционных линиях. Проведены определение филогенетических отношений по последовательностям пяти генов 11 видов дрозофил группы virilis и оценка равномерности хода молекулярных часов в отдельных филогенетических линиях данной группы видов. Показано, что D. kanekoi, D. ezoana и D. littoralis образуют отдельный кластер, наиболее близкий к субфиладе montana. Неравномерность хода молекулярных часов показана для высококонсервативных последовательностей mt 12S-16S rRNA и Ras1 генов, замены в которых преимущественно нейтральны. Показано нарушение хода молекулярных часов между отдельными филадами и между родословными древами видов субфилад lummei и kanekoi.

The aim of this study is to test the hypothesis about an inconsistency in time estimation of the divergence and topology of species Drosophila kanekoi, D. ezoana, and D. littoralis which is caused by the irregular accumulation rate of replacements in different DNA sequences used for analysis and in evolutionary lineages. The phylogenetic relationships based on sequences of five genes among 11 Drosophila species of the virilis group are revised, and estimation of molecular clock regularity in several phylogenetic lineages of this group is given. It was shown that Drosophila kanekoi, D. ezoana, and D. littoralis contituted in a single cluster, which was most related to the subphylad montana. The irregularity of molecular clocks was shown for the highly conservative sequences of the mt 12S-16S rRNA and Ras1 genes, the replacements of which were predominantly neutral. The irregularity of the molecular clock between several phylads and phylogenetic trees of subphylads lummei and kanekoi was revealed.

The steadiness of the molecular clock was estimated in 11 Drosophila species of the virilis group by sequences of five genes by applying Tajima’s Simple Method. The main characteristic of this method is the independence of phylogenetic constructions. The obtained results have completely confirmed the conclusions drawn relying on the application of the two-cluster test and the branch-length test. In addition, irregularity of the molecular clock was found in some linlages of the D. virilis species group.

The aim of this study is to test the hypothesis about an inconsistency in time estimation of the divergence and topology of species Drosophila kanekoi, D. ezoana, and D. littoralis which is caused by the irregular accumulation rate of replacements in different DNA sequences used for analysis and in evolutionary lineages. The phylogenetic relationships based on sequences of five genes among 11 fruit fly species of virilis group are revised, and estimation of molecular clock regularity in several phylogenetic lineages of this group is given. It was shown that Drosophila kanekoi, D. ezoana, and D. littoralis assembled in a single cluster, which was most related to the subfilade montana. The irregularity of molecular clocks was shown for the high conservative sequences of mt 12S-16S.

The t-complex includes a complex system of genes localized in the proximal region of chromosome 17 of house mouse Mus musculus. The results of microsatellite analysis of laboratory stocks of house mice carrying t 12, t w5, t w12, and t w73 haplotypes and wild mice from natural populations of Russia (Volgograd, Rostov, Saratov oblasts, and Kalmykia), Armenia, Bulgaria, Iran, and Mongolia performed by the PCR method with the use of eight pairs of D17Mit primers (16, 21, 23, 28, 32, 57, 63, 78) are presented. These pairs of primers amplify microsatellite DNA sequences on mouse chromosome 17 in the region from 7.6 to 18.8 cM that correspond to inversions (In (17) 3.4). Each pair of primers recognized three to six variants of nucleotide sequences ranging in size from 90–120 bp (D17Mit 16) to 300–330 bp (D17Mit 57). In most cases, two variants of nucleotide sequences were detected in each individual, i. e., most individuals were heterozygous for the microsatellite loci under study. The highest similarity of the spectra of microsatellite DNA fragments was revealed in laboratory stocks of house mice carrying the t w5 and t w73 haplotypes. The spectra of animals from the Rostov and Volgograd oblasts appeard to be most similar to them. The microsatellite spectra of individuals from Iran closely resemble the spectrum of an individual from Armenia. It was demonstrated that amplified microsatellite fragments localized in the region of the t-complex can be used to identify representatives of the Mus genus from wild populations.

Проведен сравнительный анализ группы близкородственных видов Drosophila (D. virilis, D. lummei, D. novamexicana, D. americana texana, D. flavomontana, D. montana, D. borealis, D. lacicola, D. littoralis, D. kanekoi, D. ezoana) по неполной последовательности гена Ras1. Полученная картина взаимоотношения видов соответствует той, которая предполагалась ранее на основании анализа морфологических и цитогенетических признаков. Приведены статистические данные в пользу нейтральности рассматриваемых замен в гене Ras1. Такой характер эволюции гена Ras1 придает большую надежность реконструкции филогенетических отношений близких видов. Итоговое дерево для основных филад выглядит следующим образом: (D. virilis (D. lummei, D. montana, D. ezoana)).

Comparative analysis of a group of closely related Drosophila species (D. virilis, D. lummei, D. novamexicana, D. americana texana, D. flavomontana, D. montana, D. borealis, D. lacicola, D. littoralis, D. kanekoi, and D. ezoana) was conducted based on an incomplete sequence of gene Ras1. The pattern of the relationships among the species corresponded to that expected from analysis of morphological and cytogenetic characters. Statistical data favoring neutrality of the substitutions examined in the Ras1 gene are presented. This character of the gene Ras1 evolution confers more reliability to reconstruction of phylogenetic relationships among closely related species. The resultant tree for main phylads of the group is as follows: (D. virilis, D. lummei, D. montana, D. ezoana).

Blot-hybridization analysis with the use of the t-specific probe D17Leh66 has been used to study DNA of various representatives of family Muridae. Hamsters from genus Phodopus have no homologs of this probe, whereas African rats from genus Lophuromys have some homologous elements. This indicates that sequence D17Leh66 is ancient and was probably present in the common ancestor of family Muridae.

To study structural organization and polymorphism of the proximal part of chromosome 17, a hybridization analysis of DNA from mice of different origin was carried out using four t-specific probes. Results of the analysis allow us to conclude that the DNA element copy number is quantitatively unstable and differs in distribution in both newly formed recombinant haplotypes and in wild-type chromosome 17. Probe Tu66 was used to study D17Leh66-element organization of Mus abbotti and Mus hortulanus mice. Three types of D17Leh66-elements were identified in the genomes of these species. The copy number of each type of DNA element varied in the: genome of each of four studied species. Homologs to t-specific Tu66 and Tu119 probes were found in the genome of Rattus norvegicus rat. The data obtained are discussed with respect to the evolution of the proximal part of Mus mouse, chromosome 17.

The origin and ultrastructure of the cells, encapsulating foreign body in peritoneal cavity of xenogeneic (rat in mouse) radiation chimeras was studied. The donor nature of the cells was identified by their karyotype and by DNA hybridization with rat ID-element. Cells with ultrastructural characteristics of fibroblasts encapsulating foreign body in the peritoneal cavity of the xenogeneic radiation chimeras were shown to originate from the transplanted (donor) bone marrow.