Chemical Resolution of an Epitope Recognized by Blood Group Antibodies Capable of Binding Both A and B Red Blood Cells.

The high specificity of human antibodies to blood group A and B antigens is impressive, especially when considering the structural difference between these antigens (tetrasaccharides) is a NHAc versus a hydroxyl group on the terminal monosaccharide residue. It is well established that in addition to anti-A and anti-B there is a third antibody, anti-A,B capable of recognizing both A and B antigens. To analyze this AB specificity, we synthesized a tetrasaccharide, where the NHAc of the A antigen was replaced with an NH2. This NH2 group was then used to attach the glycan to an affinity resin, creating an AB epitope (ABep) adsorbent where the critical site for recognition by A and B antibodies was not accessible, while the rest of the (conformationally compact) tetrasaccharide remained accessible. Anti-ABep antibodies were then isolated from blood group O donors and found to have expected A,B specificity against immobilized and red cell bound synthetic antigens, including ABep, and were able to agglutinate both A and B red cells. The amount of these anti-ABep (anti-A,B) antibodies found in the blood of group O donors was comparable to levels of anti-A and anti-B found in group B and A individuals. Using STD-NMR the location for the AB epitope on the tetrasaccharide was found.

Specificity profile of αGal antibodies in αGalT KO mice as probed with comprehensive printed glycan array: Comparison with human anti-Galili antibodies.

BACKGROUND: The α1,3-galactosyltransferase gene-knockout (GalT KO) mice are able to produce natural anti-αGal antibodies apparently without any specific immunization. GalT KO mice are commonly used as a model immunological system for studying anti-αGal responses to Gal-positive xenografts in human. In this study, we compared the specificity of mouse and human αGal antibodies to realize the adequacy of the murine model. METHODS: Using hapten-specific affinity chromatography antibodies against Galα1-3Galß1-4GlcNAcß epitope were isolated from both human and GalT KO mice blood sera. Specificity of isolated antibodies was determined using a printed glycan array (PGA) containing 400 mammalian glycans and 200 bacterial polysaccharides. RESULTS: The quantity of isolated specific anti-Galα antibodies corresponds to a content of <0.2% of total Ig, which is an order of magnitude lower than that generally assumed for both human and murine peripheral blood immunoglobulin, with a high predominance of IgM over IgG (95% vs 5%). Analysis using a printed glycan array has demonstrated that (a) antibodies from both species bind not only the Galα1-3Galß1-4GlcNAcß epitope, but also unrelated glycans; (b) particularly, for human (but not mouse) antibodies the best binders appear to be bacterial polysaccharides; (c) the profile of mouse antibodies is broader, it is noteworthy that they recognize a variety of human blood group B epitopes and even glycans without the α-galactosyl residue. CONCLUSIONS: We believe that the mouse model should be used cautiously in xenotransplantation experiments when the fine epitope specificity of antibodies is critical.

First report of fig mosaic virus on fig in Russia.

Fig mosaic virus (FMV) (genus Emaravirus in the family Fimoviridae) is considered the etiological agent of fig mosaic disease (FMD) that is recorded in most of the fig growing areas with an average global infection rate of 33%. The multipartite FMV genome is comprised of six negative monocistronic ssRNAs, each of which is separately encapsidated (Preising et al. 2020). Although FMD-like symptoms, which include mosaic, chlorotic ringspots, and oak leaf patterns, were observed in approximately a third of 400 fig accessions in the Nikita Botanical Gardens, Yalta, Russia (Mitrofanova et al. 2016), FMV has not been identified as the causal agent of the disease. In June of 2020, total RNA was isolated from symptomatic leaves of 59 thirty two-year-old trees representing 31 local and 27 introduced Ficus carica L. cultivars and a single F. pseudocarica Miq. tree using RNeasy Plant Mini kit (Qiagen, USA). FMV was tested by RT-PCR using primer sets E5 (Elbeaino et al. 2009) and EMARAVGP (Walia et al. 2009), which amplify a 302-bp fragment of RNA1 and a 468-bp fragment of RNA2, respectively. PCR products of the expected sizes were generated in all samples, indicating a high FMV incidence in the plantings. The genome sequences of FMV isolates from F. carica cvs. Bleuet, Kraps di Hersh, Smena, Temri, and F. pseudocarica (Fig. S1) were determined by high-throughput sequencing on MiSec Illumina platform. Double-stranded RNA was isolated from FMV-positive leaves using Viral Gene-spin™ Viral DNA/RNA Extraction Kit (iNtRON, Korea), followed by cDNA library preparation with the NEBNext® Ultra™ II RNA Library Prep Kit (New England Biolabs, USA). In average, 695,000 quality-filtered 150 bp pair-ended reads per a library were produced and used in a de novo assembly using metaSpades program version 3.14 (Nurk et al. 2017). In each of five samples, BLASTn analysis found six FMV-related contigs. The contigs spanned 99 to 100% of corresponding genomic segments of the most closely related isolates. In addition to FMV, fig cryptic virus-related contigs were also detected in some samples. The FMV contigs covering RNA1 to RNA6 had the highest identity to corresponding genomic segments of isolates AM941711 (96.5 to 96.6%), FM864225 (94.4 to 94.6%), FM991954 (97.9 to 98.2%), AB697863 (96.4 to 96.6%), AB697879 (93.3 to 93.4%), and AB697895 (95.4 to 97.0%), respectively. Five Russian isolates shared 99.2 to 100% nucleotide sequence identity, depending on the genomic segment. Their sequences were deposited in GenBank under accession numbers MW201216 to MW201230 and MW208662 to MW208676. Phylogenetic analysis of six ORFs showed that ORF1 to ORF3 and ORF6 of the Russian isolates clustered with FMV isolates from Italy while ORF4 grouped with the isolate JTT-Pa (AB697863) from Japan (Fig. S2). ORF5 of the Russian isolates formed a separate cluster with the isolates SB1 and SB2 from Serbia and JTT-Vi from Japan (AB697879 to AB697884). Incongruency of phylogenetic relationship among the genomic segments suggests reassortment among ancestors of the Russian FMV isolates. In addition, similar to the SB1, SB2 and JTT-Vi, ORF5 of the Russian isolates encodes a protein of 486 amino acid (aa) residues in contrast to the corresponding protein of Italian isolates consisting of 502 aa. To the best of our knowledge, this is the first report of FMV in Russia. This finding not only expands the information on the geographical distribution of FMV, but also extends knowledge on F. pseudocarica as a natural host of the virus.

Are there specific antibodies against Neu5Gc epitopes in the blood of healthy individuals?

Strong discrepancies in published data on the levels and epitope specificities of antibodies against the xenogenic N-glycolyl forms of sialoglycans (Hanganutziu-Deicher Neu5Gcɑ2-3Galß1-4Glc and related antigens) in healthy donors prompted us to carry out a systematic study in this area using the printed glycan array and other methods. This article summarizes and discusses our published and previously unpublished data, as well as publicly available data from the Consortium for Functional Glycomics. As a result, we conclude that (1) the level of antibodies referred to as anti-Neu5Gc in healthy individuals is low; (2) there are antibodies that seem to interact with Neu5Gc-containing epitopes, but in fact they recognize internal fragments of Neu5Gc-containing glycans (without sialic acids), which served as antigens in the assays used and; (3) a population capable of interacting specifically with Neu5Gc (it does not bind the corresponding NAc analogs) does exist, but it binds the monosaccharide Neu5Gc better than the entire glycans containing it. In other words, in healthy donors, there are populations of antibodies capable of binding the Neu5Gc monosaccharide or the inner core -Galß1-4Glc, but very few true anti-Neu5Gcɑ2-3Galß1-4Glc antibodies, i.e., antibodies capable of specifically recognizing the entire trisaccharide.

Glycan-binding profile of DC-like cells.

Modification of vaccine carriers by decoration with glycans can enhance binding to and even targeting of dendritic cells (DCs), thus augmenting vaccine efficacy. To find a specific glycan-"vector" it is necessary to know glycan-binding profile of DCs. This task is not trivial; the small number of circulating blood DCs available for isolation hinders screening and therefore advancement of the profiling. It would be more convenient to employ long-term cell cultures or even primary DCs from murine blood. We therefore examined whether THP-1 (human monocyte cell line) and DC2.4 (immature murine DC-like cell line) could serve as a model for human DCs. These cells were probed with a set of glycans previously identified as binding to circulating human CD14low/-CD16+CD83+ DCs. In addition, we tested a subpopulation of murine CD14low/-CD80+СD11c+CD16+ cells reported as relating to the human CD14low/-CD16+CD83+ cells. Manα1-3(Manα1-6)Manß1-4GlcNAcß1-4GlcNAcß bound to both the cell lines and the murine CD14low/-CD80+СD11c+CD16+ cells. Primary cells, but not the cell cultures, were capable of binding GalNAcα1-3Galß (Adi), the most potent ligand for binding to human circulating DCs. In conclusion, not one of the studied cell lines proved an adequate model for DCs processes involving lectin binding. Although the glycan-binding profile of BYRB-Rb (8.17)1Iem mouse DCs could prove useful for assessing human DCs, important glycan interactions were missing, a situation which was aggravated when employing cells from the BALB/c strain. Accordingly, one must treat results from murine work with caution when seeking vaccine targeting of human DCs, and certainly should avoid cell lines such as THP-1 and DC2.4 cells.

Molecular phylogeny of the extinct Steller's sea cow and other Sirenia species based on their complete mitochondrial genomes.

The Steller's sea cow - Hydrodamalis gigas (Dugongidae: Sirenia) - is an extinct herbivorous marine mammal which inhabited the North Pacific Ocean during the Pleistocene and Holocene. H. gigas was the largest member of the Sirenia order and disappeared in the middle of the 18th century. Here, we present the complete sequence of the mitochondrial genome of this extinct animal. The Steller's sea cow mitochondrial DNA (mtDNA) is 16,872 base pairs (bp) in length and contains a set of mitochondrial genes typical for mammals. Phylogenetic analysis based on complete mitochondrial genomes of the sirenian species allows accurate assessment of the degree of their mitogenomic diversification during millions of years of evolution.

New insights from Opisthorchis felineus genome: update on genomics of the epidemiologically important liver flukes.

BACKGROUND: The three epidemiologically important Opisthorchiidae liver flukes Opisthorchis felineus, O. viverrini, and Clonorchis sinensis, are believed to harbour similar potencies to provoke hepatobiliary diseases in their definitive hosts, although their populations have substantially different ecogeographical aspects including habitat, preferred hosts, population structure. Lack of O. felineus genomic data is an obstacle to the development of comparative molecular biological approaches necessary to obtain new knowledge about the biology of Opisthorchiidae trematodes, to identify essential pathways linked to parasite-host interaction, to predict genes that contribute to liver fluke pathogenesis and for the effective prevention and control of the disease. RESULTS: Here we present the first draft genome assembly of O. felineus and its gene repertoire accompanied by a comparative analysis with that of O. viverrini and Clonorchis sinensis. We observed both noticeably high heterozygosity of the sequenced individual and substantial genetic diversity in a pooled sample. This indicates that potency of O. felineus population for rapid adaptive response to control and preventive measures of opisthorchiasis is higher than in O. viverrini and C. sinensis. We also have found that all three species are characterized by more intensive involvement of trans-splicing in RNA processing compared to other trematodes. CONCLUSION: All revealed peculiarities of structural organization of genomes are of extreme importance for a proper description of genes and their products in these parasitic species. This should be taken into account both in academic and applied research of epidemiologically important liver flukes. Further comparative genomics studies of liver flukes and non-carcinogenic flatworms allow for generation of well-grounded hypotheses on the mechanisms underlying development of cholangiocarcinoma associated with opisthorchiasis and clonorchiasis as well as species-specific mechanisms of these diseases.

Genome-Wide DNA Methylation Profiling Reveals Epigenetic Adaptation of Stickleback to Marine and Freshwater Conditions.

The three-spined stickleback (Gasterosteus aculeatus) represents a convenient model to study microevolution-adaptation to a freshwater environment. Although genetic adaptations to freshwater environments are well-studied, epigenetic adaptations have attracted little attention. In this work, we investigated the role of DNA methylation in the adaptation of the marine stickleback population to freshwater conditions. DNA methylation profiling was performed in marine and freshwater populations of sticklebacks, as well as in marine sticklebacks placed into a freshwater environment and freshwater sticklebacks placed into seawater. We showed that the DNA methylation profile after placing a marine stickleback into fresh water partially converged to that of a freshwater stickleback. For six genes including ATP4A ion pump and NELL1, believed to be involved in skeletal ossification, we demonstrated similar changes in DNA methylation in both evolutionary and short-term adaptation. This suggested that an immediate epigenetic response to freshwater conditions can be maintained in freshwater population. Interestingly, we observed enhanced epigenetic plasticity in freshwater sticklebacks that may serve as a compensatory regulatory mechanism for the lack of genetic variation in the freshwater population. For the first time, we demonstrated that genes encoding ion channels KCND3, CACNA1FB, and ATP4A were differentially methylated between the marine and the freshwater populations. Other genes encoding ion channels were previously reported to be under selection in freshwater populations. Nevertheless, the genes that harbor genetic and epigenetic changes were not the same, suggesting that epigenetic adaptation is a complementary mechanism to selection of genetic variants favorable for freshwater environment.

Glycan recognition by human blood mononuclear cells with an emphasis on dendritic cells.

Dendritic cells (DCs) play crucial roles in innate and adaptive immune response, for which reason targeting antigen to these cells is an important strategy for improvement of vaccine development. To this end, we explored recognition of DCs lectins by glycans. For selection of the glycan "vector", a library of 229 fluorescent glycoprobes was employed to assess interaction with the CD14low/-CD16+CD83+ blood mononuclear cell population containing the DCs known for their importance in antigen presentation to T-lymphocytes. It was found that: 1) the glycan-binding profiles of this CD14low/-CD16+CD83+ subpopulation were similar but not identical to DCs of monocyte origin (moDCs); 2) the highest percentage of probe-positive cells in this CD14 low/-CD16+CD83+ subpopulation was observed for GalNAcα1-2Galß (Adi), (Neu5Acα)3 and three mannose-reach glycans; 3) subpopulation of CD14low/-CD16+ cells preferentially bound 4'-O-Su-LacdiNAc. Considering the published data on specificity of DCs binding, the glycans showing particular selectivity for the CD14 low/-CD16+CD83+ cells are likely interacting with macrophage galactose binding lectin (MGL), siglec-7 and dectin-2. In contrast, DC-SIGN is not apparently involved, even in case of mannose-rich glycans. Taking into consideration potential in vivo competition between glycan "vectors" and glycans within glycocalyx, attempting to target vaccine to DCs glycan-binding receptors should focus on Adi and (Neu5Acα)3 as the most promising vectors.

Tracking the origins of Yakutian horses and the genetic basis for their fast adaptation to subarctic environments.

Yakutia, Sakha Republic, in the Siberian Far East, represents one of the coldest places on Earth, with winter record temperatures dropping below -70 °C. Nevertheless, Yakutian horses survive all year round in the open air due to striking phenotypic adaptations, including compact body conformations, extremely hairy winter coats, and acute seasonal differences in metabolic activities. The evolutionary origins of Yakutian horses and the genetic basis of their adaptations remain, however, contentious. Here, we present the complete genomes of nine present-day Yakutian horses and two ancient specimens dating from the early 19th century and ∼5,200 y ago. By comparing these genomes with the genomes of two Late Pleistocene, 27 domesticated, and three wild Przewalski's horses, we find that contemporary Yakutian horses do not descend from the native horses that populated the region until the mid-Holocene, but were most likely introduced following the migration of the Yakut people a few centuries ago. Thus, they represent one of the fastest cases of adaptation to the extreme temperatures of the Arctic. We find cis-regulatory mutations to have contributed more than nonsynonymous changes to their adaptation, likely due to the comparatively limited standing variation within gene bodies at the time the population was founded. Genes involved in hair development, body size, and metabolic and hormone signaling pathways represent an essential part of the Yakutian horse adaptive genetic toolkit. Finally, we find evidence for convergent evolution with native human populations and woolly mammoths, suggesting that only a few evolutionary strategies are compatible with survival in extremely cold environments.

Between Lake Baikal and the Baltic Sea: genomic history of the gateway to Europe.

BACKGROUND: The history of human populations occupying the plains and mountain ridges separating Europe from Asia has been eventful, as these natural obstacles were crossed westward by multiple waves of Turkic and Uralic-speaking migrants as well as eastward by Europeans. Unfortunately, the material records of history of this region are not dense enough to reconstruct details of population history. These considerations stimulate growing interest to obtain a genetic picture of the demographic history of migrations and admixture in Northern Eurasia. RESULTS: We genotyped and analyzed 1076 individuals from 30 populations with geographical coverage spanning from Baltic Sea to Baikal Lake. Our dense sampling allowed us to describe in detail the population structure, provide insight into genomic history of numerous European and Asian populations, and significantly increase quantity of genetic data available for modern populations in region of North Eurasia. Our study doubles the amount of genome-wide profiles available for this region. We detected unusually high amount of shared identical-by-descent (IBD) genomic segments between several Siberian populations, such as Khanty and Ket, providing evidence of genetic relatedness across vast geographic distances and between speakers of different language families. Additionally, we observed excessive IBD sharing between Khanty and Bashkir, a group of Turkic speakers from Southern Urals region. While adding some weight to the "Finno-Ugric" origin of Bashkir, our studies highlighted that the Bashkir genepool lacks the main "core", being a multi-layered amalgamation of Turkic, Ugric, Finnish and Indo-European contributions, which points at intricacy of genetic interface between Turkic and Uralic populations. Comparison of the genetic structure of Siberian ethnicities and the geography of the region they inhabit point at existence of the "Great Siberian Vortex" directing genetic exchanges in populations across the Siberian part of Asia. Slavic speakers of Eastern Europe are, in general, very similar in their genetic composition. Ukrainians, Belarusians and Russians have almost identical proportions of Caucasus and Northern European components and have virtually no Asian influence. We capitalized on wide geographic span of our sampling to address intriguing question about the place of origin of Russian Starovers, an enigmatic Eastern Orthodox Old Believers religious group relocated to Siberia in seventeenth century. A comparative reAdmix analysis, complemented by IBD sharing, placed their roots in the region of the Northern European Plain, occupied by North Russians and Finno-Ugric Komi and Karelian people. Russians from Novosibirsk and Russian Starover exhibit ancestral proportions close to that of European Eastern Slavs, however, they also include between five to 10 % of Central Siberian ancestry, not present at this level in their European counterparts. CONCLUSIONS: Our project has patched the hole in the genetic map of Eurasia: we demonstrated complexity of genetic structure of Northern Eurasians, existence of East-West and North-South genetic gradients, and assessed different inputs of ancient populations into modern populations.

Biantennary oligoglycines and glyco-oligoglycines self-associating in aqueous medium.

Oligoglycines designed in a star-like fashion, so-called tri- and tetraantennary molecules, were found to form highly ordered supramers in aqueous medium. The formation of these supramers occurred either spontaneously or due to the assistance of a mica surface. The driving force of the supramer formation is hydrogen bonding, the polypeptide chain conformation is related to the folding of helical polyglycine II (PG II). Tri- and tetraantennary molecules are capable of association if the antenna length reach 7 glycine (Gly) residues. Properties of similar biantennary molecules have not been investigated yet, and we compared their self-aggregating potency with similar tri- and tetraantennary analogs. Here, we synthesized oligoglycines of the general formula R-Gly n -Х-Gly n -R (X = -HN-(СН2) m -NH-, m = 2, 4, 10; n = 1-7) without pendant ligands (R = H) and with two pendant sialoligands (R = sialic acid or sialooligosaccharide). Biantennary oligoglycines formed PG II aggregates, their properties, however, differ from those of the corresponding tri- and tetraantennary oligoglycines. In particular, the tendency to aggregate starts from Gly4 motifs instead of Gly7. The antiviral activity of end-glycosylated peptides was studied, and all capable of assembling glycopeptides demonstrated an antiviral potency which was up to 50 times higher than the activity of peptide-free glycans.

Koban culture genome-wide and archeological data open the bridge between Bronze and Iron Ages in the North Caucasus.

The North Caucasus played a key role during the ancient colonization of Eurasia and the formation of its cultural and genetic ancestry. Previous archeogenetic studies described a relative genetic and cultural continuity of ancient Caucasus societies, since the Eneolithic period. The Koban culture, which formed in the Late Bronze Age on the North Caucasian highlands, is considered as a cultural "bridge" between the ancient and modern autochthonous peoples of the Caucasus. Here, we discuss the place of this archeological culture and its representatives in the genetic orbit of Caucasian cultures using genome-wide SNP data from five individuals of the Koban culture and one individual of the early Alanic culture as well as previously published genomic data of ancient and modern North Caucasus individuals. Ancient DNA analysis shows that an ancient individual from Klin-Yar III, who was previously described as male, was in fact a female. Additional studies on well-preserved ancient human specimens are necessary to determine the level of local mobility and kinship between individuals in ancient societies of North Caucasus. Further studies with a larger sample size will allow us gain a deeper understanding of this topic.

First Report and Complete Genome Characterization of Cherry Virus A and Little Cherry Virus 1 from Russia.

Virus diseases affect the yield and fruit quality and shorten the productive life of stone fruits (Prunus spp. in the family Rosaceae). Of over fifty known viruses infecting these crops, cherry virus A (CVA) is among the most common, and little cherry virus 1 (LChV1) is one of the most economically important. Using high-throughput sequencing, full-length genomes of CVA and LChV1 isolates, found on interspecies hybrids in the Prunus collection of the Nikita Botanical Gardens, Russia, were sequenced, assembled, and characterized. CVA was found in the P. cerasifera × P. armeniaca hybrid and in phylogenetic analysis clustered with non-cherry virus isolates. The LChV1 isolate Stepnoe was detected in ((P. cerasifera Ehrh. × P. armeniaca L.) × P. brigantiaca Vill.) trihybrid suggesting that both P. cerasifera and P. brigantiaca potentially can be the LChV1 hosts. The isolate Stepnoe was most closely related to the Greece isolate G15_3 from sweet cherry, sharing 77.3% identity at the nucleotide level. Possibly, the highly divergent Russian isolate represents one more phylogroup of this virus. This is the first report of CVA and LChV1 from Russia, expanding the information on their geographical distribution and genetic diversity.

Genetic Diversity of Common Olive (Olea europaea L.) Cultivars from Nikita Botanical Gardens Collection Revealed Using RAD-Seq Method.

In different countries, interest in the commercial cultivation of the olive has recently greatly increased, which has led to the expansion of its range. The Crimean Peninsula is the northern limit of the common olive (Olea europaea L.) range. A unique collection of common olive's cultivars and hybrids has been collected in the Nikitsky Botanical Gardens (NBG). The aim of this study was to assess the genetic diversity of 151 samples (total of several biological replicates of 46 olive cultivars including 29 introduced and 11 indigenous genotypes) using the ddRAD sequencing method. Structural analysis showed that the studied samples are divided into ten groups, each of which mainly includes cultivars of the same origin. Cultivars introduced to the Crimean Peninsula from different regions formed separate groups, while local cultivars joined different groups depending on their origin. Cultivars of Crimean origin contain admixtures of mainly Italian and Caucasian cultivars' genotypes. Our study showed that the significant number of Crimean cultivars contains an admixture of the Italian cultivar "Coreggiolo". Genetic analysis confirmed the synonymy for the cv. "Otur" and "Nikitskaya 2", but not for the other four putative synonyms. Our results revealed the genetic diversity of the olive collection of NBG and provided references for future research studies, especially in selection studies for breeding programs.

Ancient DNA of the Don-Hares Assumes the Existence of Two Distinct Mitochondrial Clades in Northeast Asia.

Paleoclimatic changes during the Pleistocene-Holocene transition is suggested as a main factor that led to species extinction, including the woolly mammoth (Mammuthus primigenius), Steller's sea cow (Hydrodamalis gigas) and the Don-hare (Lepus tanaiticus). These species inhabited the territory of Eurasia during the Holocene, but eventually went extinct. The Don-hare is an extinct species of the genus Lepus (Leporidae, Lagomorpha), which lived in the Late Pleistocene-Early Holocene in Eastern Europe and Northern Asia. For a long time, the Don-hare was considered a separate species, but at the same time, its species status was disputed, taking into account both morphological data and mitochondrial DNA. In this study, mitochondrial genomes of five Don-hares, whose remains were found on the territory of Northeastern Eurasia were reconstructed. Firstly, we confirm the phylogenetic proximity of the "young" specimens of Don-hare and mountain or white hare, and secondly, that samples older than 39 Kya form a completely distinct mitochondrial clade.

Characterization of Divergent Grapevine Badnavirus 1 Isolates Found on Different Fig Species (Ficus spp.).

Fig mosaic disease is spread worldwide and is believed to have a viral etiology. Divergent isolates of grapevine badnavirus 1 (GBV1), named fGBV1, were discovered on Ficus carica, F. palmata, F. virgata, and F. afghanistanica in the fig germplasm collection of the Nikita Botanical Gardens, Russia, expanding the list of viruses infecting this crop. The complete genomes of five fGBV1 isolates from F. carica and F. palmata trees were determined using high-throughput and Sanger sequencing. The genomes comprised 7283 base pairs, contained four overlapping open reading frames, were 99.7 to 99.9% identical to each other, and related to GBV1 (83.2% identity). The reverse transcriptase RNase H genome regions of fGBV1 and GBV1 share 84.6% identity, indicating that fGBV1 is a divergent isolate of GBV1, which was found on the new natural hosts from a different family (Moraceae). Further, fGBV1-specific primers were developed to detect the virus using RT-PCR. Survey of 47 trees, belonging to four fig species and 14 local and introduced F. carica cultivars, showed the high fGBV1 prevalence in the collection (93.6%), including trees with no obvious symptoms of fig mosaic disease.

Intergeneric hybridization of two stickleback species leads to introgression of membrane-associated genes and invasive TE expansion.

Interspecific hybridization has occurred relatively frequently during the evolution of vertebrates. This process usually abolishes reproductive isolation between the parental species. Moreover, it results in the exchange of genetic material and can lead to hybridogenic speciation. Hybridization between species has predominately been observed at the interspecific level, whereas intergeneric hybridization is rarer. Here, using whole-genome sequencing analysis, we describe clear and reliable signals of intergeneric introgression between the three-spined stickleback (Gasterosteus aculeatus) and its distant mostly freshwater relative the nine-spined stickleback (Pungitius pungitius) that inhabit northwestern Russia. Through comparative analysis, we demonstrate that such introgression phenomena apparently take place in the moderate-salinity White Sea basin, although it is not detected in Japanese sea stickleback populations. Bioinformatical analysis of the sites influenced by introgression showed that they are located near transposable elements, whereas those in protein-coding sequences are mostly found in membrane-associated and alternative splicing-related genes.

A de novo genome assembly of cultivated Prunus persica cv. 'Sovetskiy'.

Prunus persica is one of the main stone fruit crops in Crimea and southern Russia. The P. persica genome has recently been sequenced and annotated in good quality. However, for a deeper assessment of the peach genome, it is necessary to include in the research other cultivars that are in the collection of the Nikitsky Botanical Garden. The cultivars of the Nikitsky Botanical Garden are unique and differ from Western European and American ones, as they are derived from cultivars and forms originating from Central Asian, North Caucasian, Transcaucasian and Eastern European countries. In this paper, we present the assembly of the P. persica cv. 'Sovetskiy' genome obtained using Oxford Nanopore long reads and Illumina short reads by hybrid assembly methods. The assembled genome of P. persica cv. 'Sovetskiy' is 206.26 MB in 226 scaffolds, with N50 24 Mb, including 8 chromosomes. It contains 27140 coding genes, 26973 (99.38%) of which are annotated in at least one functional database. More than 36.05% of the genome regions were identified as repeating elements.