The Wheat Genetic Resources Department of VIR treats Triticum durum Desf. as a separate species. It contains 2 subspecies: subsp. durum and subsp. horanicum. Subsp. horanicum Vav. shows the highest spike density. Subsp. durum – the durum wheat proper – is characterized by a major variation of spike density, grain size and form. The subspecies also has liguleless forms and those with strongly pubescent leaves. The subsp. durum is represented by 6 groups of botanical varieties (convarieties): durum, durocompactum, aglossicon, villosum, falcatum, and caucasicum. Convar. durum has three subconvarieties: durum, muticum and duroramosum. At the time of the development of the classification 121 botanical varieties were described within T. durum. They were identified by a combination of characteristics such as the presence or absence of pubescent straw under the spike, pubescent or glabrous glumes, the roughness of awns (smooth or rough), glume color (white, red, gray, smoked-grayish or black on white or red background), awn color (same color as that of glumes or black), kernel color (white, red or purple). The principle of selection of botanical varieties is based on the combination of a large number of signs, giving a large number of possible options. It is very likely that most of them are not found in nature, but the probability of finding a new botanical variety or the presence of various forms can be increased as the research of polymorphism in accessions of the durum wheat collection in different ecological and geographical conditions. The objects of research were about 6000 accessions from the VIR durum wheat genetic collection, which had been grown in different ecological and geographical conditions during for 15 years. Identification of the accessions was carried out in accordance with the classification used by the Wheat GR department in its work with the collection. As a result of their own field research in ICARDA (Syria, Tel Hadya) and identification of accessions obtained after reproduction on the VIR experimental station, we have identified 10 new botanical varieties and 12 forms of T. durum to supplement the classification. For each of them the diagnosis is given, the type is defined, a herbarium (autotype) and photos are provided.

The Abyssinian pea (Pisum abyssinicum A. Br.), concerned in this review, is known from Ethiopia and Yemen, where it is cultivated along with the common pea (Pisum sativum L. subsp. sativum). The continuously reproduced notion of its possible spontaneous occurrence in the wild ascends to suppositions made in the XIX century and is not based on any actual data. P. abyssinicum is of practical interest owing to its extra early ripening and resistance to bacterial blight. Morphologically it is very similar to P. sativum but its crossability with it is bad as either seed or pollen parent. Traditionally this reproductive barrier was associated with karyological differences. The Abyssinian pea karyotype is variable as 1–2 reciprocal translocations were reported. At the same time there are accessions not differing from the standard karyotype of P. sativum with respect to reciprocal translocations, yet their crossability with the latter is very low and the pollen fertility of F1 and F2 hybrids is lowered. Data were reported on influence of the region of Linkage Group III, containing a gene known to participate in the conflict of nucleus and plastids in remote crosses of peas, on the pollen fertility of hybrids with abyssinian pea. With their karyological variability, the known accessions of the Abyssinian pea are very close to each other genetically, as they diverged just about 4000 years ago. The presence of alleles of molecular markers common with Pisum fulvum Sibth. et Smith on the one hand and P. sativum L. subsp. elatius (Bieb.) Schmalh. on the other hand evidences in favour of an old hypotheses by L.I. Govorov that the Abyssinian pea originated from their spontaneous hybrid. This spontaneous cross may have taken place under cultivation, in Yemen or Afar Depression. A representative of P. sativum subsp. elatius was revealed, the F1 hybrids of which with the Abyssinian pea as a seed parent had fully fertile pollen. P. abyssinicum× P. fulvum crosses provide the best hybrid seed outcome among remote crosses conducted, so that P. abyssinicum can be used as a ‘bridge’ for gene introgression from P. fulvum to P. sativum. Rather a high evel of reproductive isolation of the Abyssinian pea from other representatives of the genus conforms the biological species concept, however the disposition of P. abyssinicum accessions as a small cluster among accessions of P. sativum subsp. elatius on molecular phylogeny reconstructions violates the phylogenetic species concept. Most authors assume the Abyssinian pea as a species, Pisum abyssinicum, some as a subspecies, P. sativum subsp. abyssinicum (A. Br.) Berger. Perhaps it would be most correct to consider it as a hybridogenic species. Because of the recent subsuming of the genus Pisum L. into the genus Lathyrus and with respect to the existing name Lathyrus abyssinicus A. Br. (a synonym of L. sativus L.), the Abyssinian pea is given a new name Lathyrus schaeferi (A. Braun) Kosterin nomen novum pro Pisum abyssinicum A. Braun), in honour of Hanno Schaefer, who substantiated the revision of tribe Fabeae by molecular reconstruction of its phylogeny. New combinations of Lathyrus sectio Pisum (L.) Kosterin combinatio nova and Lathurus fulvus (Sibthrop et Smith) Kosterin combinatio nova are proposed.

Chickpea (Cicer arietinum L.) is the second grain legume for the area of cultivation in the world, and the third for the production. However, modern cultivars of chickpea are typically susceptible to a variety of diseases, and have modest drought tolerance. The improvement of the crop for adaptability сould be carried out via introgression of valuable traits genes from old landraces collected in the centers of chickpea origin and diversity: the primary – Turkey and secondary – Ethiopia. The N.I. Vavilov All-Russian Institute of Plant Genetic Resources (thereafter VIR) preserves 3380 chickpea accessions, with landraces representing over a half of them. Here, the results of analysis of variability of 11 biological, morphological and economic-valuable traits in 1082 chickpea landraces descended from 60 countries are briefly driven. More in detail the sample of 75 landraces from Turkey and 24 landraces from Ethiopia (centres of chickpea origin) which had been sampled there 90 years ago have been studied. We analyzed the phenotypic variability with a treatment of 15 traits. The traits were studied using component analyses. Geographic regularities of certain traits in the studied accessions have been revealed. Ethiopian landraces are relatively homogeneous, belonging mostly to desi-type, and having fewer small, dark, and angular seeds, a short maturation period. They belong to the Abyssinian eco-geographical group, absolutely unique and endemic to Ethiopia. Turkish landraces are characterized by much higher diversity for the majority of phenotypes, covering almost the entire range of traits specified in chickpea descriptors. In this region, together with landraces typical for Turkey, there are those from the western Mediterranean and from the areas bordering with Turkey to the east. Landraces from primary and secondary centers of origin differed on the range of variability of the traits studied. The smaller degree of variation and primitiveness of the most traits and lower seed productivity in Ethiopian landraces in comparison with Turkish ones indicates a greater breeding advancement of the latter. Useful traits for breeding are present in the landraces from both centers of origin and diversity.

Introduction to industrial horticulture varieties of quince, characterized by winter hardiness, high productivity and good product qualities and valuable chemical composition, is one of the priorities in breeding. The article presents a selection of parental pairs, taking into account their biologically and economically valuable traits: Ispolinskaya (yield of large fruits); Cаunchi 8 (fruit quality); Zolotistaya and Muskatnaya (yield, high winter hardiness and drought resistance); and Kubanskaya (tree growth restraint). Varieties with horizontal resistance to monilia are Muskatnaya, Novogodnyaya, Urozaijnaya kubanskaya and Sophia. The timing of flowering was determined for early-flowering Dyuna and Nivushka and late-flowering Aurora, Novogodnyaya and Rumo. Aurora, Zoloto skifov, Podarochnaya, Urozaijnaya kubanskaya and Sophia were identified as high-yield varieties, with maximum environmental adaptation to adverse environmental factors. Based on hybridological analysis, the inherited traits that characterize their commercial quality (apple-shaped fruits and fruit size) have been identified; the varieties with the most stable technical performance (the coefficient of variation V = 8.5–10.0 %) are Novogodnyaya, Nivushka and Podarochnaya. Varietal dif­ferences in the content of vitamins and polyphenols have been identified between new varieties and cultivars taken for crossing: Zolotistaya (28.4 mg/100 g), Novogodnyaya (33.3 mg/100 g) and Podarochnaya (32.3 mg/100 g) are high in vitamin C; Kubanochka (225.0 mg/100 g), Novogodnyaya (222.2 mg/100 g) and Podarochnaya (196.8 mg/100 g) are high in P-active catechins, which allows you to replenish your assortment of quince for the South of Russia with valuable genotypes of quince (Cydonia oblonga Mill.) competitive varieties of selection by the North-Caucasus Zonal Scientific-Research Institute of Horticulture and Viticulture.

Different molecular genetic markers are effectively used in agricultural genetic selection programs. Genetic markers can be used in commercial breeds certification performance, fast and reliable genotype identification, genetic maps creation, genetics, phylogeny and plant systematic studies, which can accelerate selection, provide effective study and culture genofond maintenance. Amaranth, in this regard, has not been studied well, there is not enough data to effectively perform amaranth marker selection or for the certification of new and existing varieties; there are inaccuracies in the systematization of the crop. Important are the questions about the origin of grain amaranth species and the processes of their evolutionary formation. Amaranth is a pseudo-cereal with a millennia-long history, it has been actively cultivated in many countries around the world in recent decades. A high level of alterability and the formation of a huge number of spontaneous hybrids in natural populations of amaranth significantly complicate the identification of individual genotypes and entire taxonomic units of Amaranthus L. Due to the lack of research and depending on the environmental conditions, the morphological markers of amaranth are not able to provide sufficient genomic information to the breeder; thus it is necessary to search for reliable genetic markers that allow the genetic diversity of the Amaranthus L. species to be studied and effectively maintained. This research includes grain amaranth species DNA polymorphism analysis. Using RAPD and ISSR technologies, 203 loci have been identified, of which 173 appear to be polymorphic, 30 monomorphic (found in all genotypes analyzed) and 13 unique (found only in one genotype). Unique and monomorphic DNA loci can be used as specific genetic markers, in particular, for the certification of breeds, which is especially important for the identification of plant material and plant genetic variability monitoring. A high level of DNA polymorphism was revealed (about 85 %), a genetic relationship between grain amaranth species established, their monophyletic origin theory verified. A. mantegazzianus Passer. was proved to be an A. caudatus L. subspecies.

The formation of plus trees assortment for seed orchards is one of the most difficult problems of contemporary forest breeding. This problem is related to the risk of inbreeding depression of the seed progeny of plus trees, which do not have any defense mechanism against self-pollination. Economically, the Scots pine is one of the most important wood species. Diverse characteristics of its needles make a subject for multidisciplinary research. Needle size is accepted as an indirect indicator of growth pine energy. Our research was focused on selection valuation of Scots pine plus trees by morphometric features of needles. Plus trees are represented by their clones in first-order seed orchards in the Nizhny Novgorod region. When collecting the source material, the elimination of differentiating effects of environmental factors and time factors was ensured. The dissimilarity of plus trees at a wide range of signs was manifested to different degrees. Because the heterogeneity of the assortment composition of the seed orchard in question was formed against the background of the aligned environmental conditions, there was every reason to consider it as being caused largely by hereditary factors. It was confirmed by the results of ANOVA. The predominant influence of distinctions between ortets was established. The influence of distinctions between the ramets was revealed – that was comparable to the residual variance. Pronounced heterogeneity of the composition and its genetic determinism set up conditions for effective multivariate comparisons of plus trees. Factor analysis formed its integrated independent variables from a common set of morphological parameters of needles. They are used in cluster analysis along with the original signs. Cluster analysis revealed in the seed orchards plus trees that are to the greatest extent different from the others. They can be combined with all the other plus trees in cross-breeding schemes to achieve the heterosis effect and to eliminate the risk of inbreeding depression.

Great attention is paid to preliminary breeding (prebreeding) when developing triploid apple cultivars. Brief characteristics of diploid gamete donors are given. It should be noted that sometimes donors of diploid gametes with necessary important traits not only have to be selected from among existing tetraploid cultivars, but also developed by a breeding way, especially in the case when in nature there are no cultivars and genotypes (donors of diploid gametes) with given traits. The authors of the paper developed form 30-47-88 (Liberty×13-6-106) by a breeding way. 30-47-88 is a complex donor of diploid gametes and scab immunity (Vf ) at once. During 1970–2015, the following work was done in apple breeding using polyploidy: 455 crossing combinations were performed; 660000 flowers were artificially pollinated; 124700 hybrid seeds were obtained and 47900 one-year-old seedlings were grown, from which after multiple rejections 13200 seedlings were planted in breeding orchards. For the first time in Russia ten apple cultivars (Avgusta, Aleksandr Boiko, Bezhin Lug, Vavilovskoye, Dariona, Maslovskoye, Orlovsky Partizan, Osipovskoye, Patriot and Yablochny Spas) have been developed from intervalence crossings and regionalized. It has been stated that apple cultivars developed at the VNIISPK are characterized, as a rule, by high productivity, better fruit marketability, greater resistance to scab and higher autogamy. Apple cultivars combining triploidy and scab immunity have been developed. Promising breeding is being performed for apple cultivars combining triploidy, scab immunity and columnar habit (Co). Brief characteristics of triploid and scab immune cultivars Vavilovskoye and Yablochny Spas developed from the intervalence crossings as well as three triploid cultivars obtained from crossings of diploid cultivars are given. It is noted that triploid apple cultivars developed at the VNIISPK are inferior to none of foreign cultivars in a complex of commercial traits and they significantly excel foreign cultivars in adaptability. Our apple cultivars may contribute to import substitution of fruit production in the country.

The results of a study of resistance to unfavorable winter conditions of new selection seedlings of apple developed in the Institute as part of priority directions of apple breeding are presented.

The goal of the work is to estimate winter hardiness of apple genotypes developed by combining scab resistance in a triploid genotype (RVi6+3х). Methods of a winter hardiness study in the field and laboratory conditions were used by modelling damage factors in a “ESPEC” PSL-2 KPN deep-freezer . It was determined that by early December the genotypes gained a good hardening and displayed the resistance of vitally important tissues to early winter frosts up to 30 °C (frost resistance component I). The genotypes were revealed that under artificial freezing bore critical temperatures –38 and –40 °C as well as –42 °C with damages of vitally important tissues at the level of Antonovka Obyknovennaya (component II). The modelling of a three-day artificial thaw (+2 °C) with the following temperature lowering to –30 °C showed that in all studied apple seedlings the damages of bark, cambium and wood were reversible and did not exceed 2.0 points while in immune, triploid forms 31-2-130 and ELS 31-36-149, the damages did not exceed 1.2 points. The winter hardiness study of selection apple seedlings allowed revealing the most winter hardy and promising genotypes: scab resistant and triploid forms 31-2-15, 31-2-115, 31-2-130 (Afrodita×13-6-106) and 31-36-149 [Veniaminovskoye×25-35-144 (Wealthy tetraploid× Papirovka tetraploid)] as well as scab resistant diploids 32-35-58 (Yubiley Moskvy×Krasa Sverdlovska) and 31-15-126 [23-16-96 (seedling 814 – open pollination)×Gulliver)]. Those genotypes displayed the resistance of vitally important tissues to early winter frosts, frosts in the middle of winter up to –40 °C at the level of Antonovka Obyknovennaya as well as to the frosts after thaws and retained the ability to restore resistance during repeated hardening after thaws. 

Features of wheat (Triticum aestivum L.) inflorescence development define its architecture and have an impact on yield potential. Wheat lines and forms with altered inflorescence morphology are important genetic resources for the study on the genetic mechanisms underlying plant developmental programs and inflorescence architecture; they are also important for practical use to increase productivity. Normally, wheat spikelets are arranged in two parallel rows along the spike axis. The SCR (screwed spike rachis) lines represent a non-standard morphotype, which is characterized by a spiral arrangement of spikelets along the spiked rachis. The study of the early stages of the inflorescence development in SCR-lines using light and scanning electron microscopy revealed that the spiral arrangement of spikelets were not related to changes at the early stage of inflorescence development, and resulted from spiral growth of spike rachis cells at later stages of spike growth. Thus, the spiral arrangement of spikelets in cereal inflorescence may have resulted not only from peculiarities of the mutual arrangement of spikelet meristems (phyllotaxis), but also from cell growth features at later stages of inflorescence growth. It was shown that SCR is inherited as a dominant monogenic trait; its expression can be modified by genotypic background. The SCR-lines characterized using light and scanning electron microscopy represent an important genetic resource for further study of the molecular-genetic mechanisms determining plant architecture. Furthermore, they can be used to develop wheat lines and cultivars with new inflorescence phenotypes.

Roots branching regulation is an important adaptive mechanism for the adaptation of plants to root environments. Elucidation of the genetic mechanisms involved in increase in the degree of plant root branching is essential in improving the responsiveness of crops to supply elements. The aim was to study the interaction of the genes SHY2 and MSG1, NPH4 and IAR2 as attributes of the root system of A. thaliana are inherited. By crossing plants of the mutant lines shy2-2×msg1-2, nph4-1×iar2-1, a segregation in F2 was observed, suggesting an interaction between the polymer SHY2 and MSG1, NPH4 and IAR2 genes. The segregation ratio of the phenotypes in F2 is 15:1. The results presented are of interest for practical use of the economically valuable trait «branching roots» in plant breeding to create varieties and hybrids with the desired properties of mineral nutrition. Our data indicate that the ability of plant roots to increase the degree of branching depends on individual genes and can be inherited through polymer gene interactions. Knowing the polymeric nature of inheritance in the root system, the length of lateral roots in the interaction of genes can be combined by crossing genes and increase the degree of branching of the roots from cultivated plants to create agrochemically effective varieties and hybrids.

The formation and maintenance of plant stem cell populations are controlled by the WOX family of homeobox-containing transcription factors. The evolution of WOX genes is considered to be one of the main reasons for flower morphology and plant architecture diversity. The stem cell regulation mechanism is considered to be conserved among flowering plants and most thoroughly studied in Arabidopsis thaliana as a model. The angiosperms morphological diversity implies that there are species-specific features inherent to this mechanism, while the basic signaling is maintained. The unique flowering achlorophyllous mycoheterotrophic plant Monotropa hypopitys obtains nutrients from the tree roots through the mycorrhizal symbiosis. In inductive conditions, the reproductive stem with bracts and an inflorescence at the top is developed from an adventitious root bud. Like other plants, M. hypopitys forms the inflorescence, flower and root meristems, presumably using conserved mechanisms regulating stem cell niche. The study of M. hypopitys homeobox genes should contribute to the knowledge about the function of WOX transcription factors and further understanding of the stem cells control mechanisms in mycoheterotrophic species. The aim of the present study was to analyze M. hypopitys root, bracts and flower transcriptomes obtained from two individual flowering plants. In total, five WOX genes have been identified and characterized by their structure, phylogeny, expression pattern, and possible functions. The assumption is that the MhyWUS1 and MhyWUS2 genes maintain the stem cell population in the inflorescence and flower meristems, MhyWOX13 has a role in the control of root stem cell niche, seed pod formation, flowering initiation, and basic cellular processes, MhyWOX4 functions in the control of cambium stem cells, and MhyWOX2 participates in the differentiation of egg cells and zygotes.

Aegilops columnaris Zhuk. is a potential source of new genes for wheat improvement. However, this species has not yet been used in practical breeding. In the present work we have for the first time reported the development and molecular-cytogenetic characterization of T. aestivum×Ae. columnaris introgression lines. Analysis has not revealed alien genetic material in five of the 20 lines we have studied, while the remaining lines carried from 1 to 3 pairs of Aegilops chromosomes as addition(s) or substitution(s) to wheat chromosomes. Altogether, five different chromosomes of Aegilops columnaris have been detected in the karyotypes of 15 lines by C-banding and fluorescent in-situ hybridization (FISH). Based on substitution spectra, these chromosomes were identified as 3Ае1, 3Ае2, 5Ае2, 6Ае1 and 6Ае2. In addition, another Aegilops chromosome has been found in the line 2305/1 as a monosomic addition; due to the lack of group-specific markers we were unable to assign this chromosome to a particular genome or a genetic group and therefore it was designated Ае-а. In several lines acrocentric and telocentric chromosomes have been revealed (Ae-b and Ae-c). It is most likely that these chromosomes were derived from unknown Aegilops chromosomes due to a large deletion. A comparison of electrophoretic spectra of gliadins in introgression lines L-2310/1 and L-2304/1 with substitutions of chromosome 6D with two different chromosomes of Ae. columnaris (these lines were assigned to the 6th homoeologous group based on C-banding data) has shown that they carry different alleles of the gliadin loci. This observation confirmed that lines L-2310/1 and L-2304/1 contained non-identical 6Ae chromosomes. Taking into consideration our previous results of FISH analyses, three other Ae. columnaris chromosomes can be assigned to homoeologous groups 1, 5 and 7 of the U-genome based on the location of 5S and 45S rDNA loci (1U and 5U) or pSc119.2 probe distribution (7U). Thus, based on our current data as well as on the results of earlier work, we can identify eight out of the 14 chromosomes of Aegilops columnaris.

The CRISPR/Cas system is the most promising among genome editing tools. It can provide the development of modified nontransgenic plants with the possibility of simultaneous multiple targeted mutations. The purpose of this review is to analyze published papers describing the utilization of the CRISPR/Cas system for crop gene modification in order to assess the potential of this technology as a new plant breeding technique. The search for “CRISPR & crop name” within article titles, abstracts and keywords in the Scopus database was carried out for 45 crops. Among a total of 206 search results, only 88 have been recognized as original articles describing editing crop genes with the CRISPR/Cas system. A total of 145 target genes of 15 crops are described in these 88 articles, including rice with the largest number of genes modified (78 genes). In these studies, the ability to get transgene-free modified plants was widely demonstrated. However, in most cases research was aimed at the approbation of the technology or was to elucidate target gene function, while modification of just 37 target genes was related with crop improvement. We present here a catalogue of these genes. In most of these cases, modifications resulted in knockout of the genes such as negative growth and development regulators or negative regulators of plant resistance. In most cases, the phenotype of modified plants was assessed, and the presence of desired changes was shown. However, since the estimated number of “negative regulators” is limited in plant genomes, the CRISPR-directed gene knockout has a restricted potential for crop improvement. Intensive application of the CRISPR/Cas system for more complicate modifications such as replacement of defect alleles by functional ones or insertion of a desired gene is required (so far reports about such modifications are very rare in crops). In addition, to provide a basis for broad practical application of CRISPR/Cas-based genome editing, more cultivars of crop species should be involved in ongoing studies. Just a few genotypes of crop species have been used for gene modifications thus far. Nevertheless, in spite of the restrictions mentioned, essential success has been achieved over a short period (3.5 years since the first publications on CRISPR/Cas application in plants).

The frequency of recombination and the patterns of crossover site distribution along the chromosomes vary considerably among animal species, including closely related species. Several hypotheses concerning the adaptive value and evolution of these variations were proposed. It was supposed that the recombination patterns of the species’ genomes are influenced by their phylogenetic history and ecology. However, most original data were obtained from mammals. The mammals show high karyological variability, which strongly influences the recombination patterns. Therefore it is important to study recombination rate and distribution in more karyologically stable taxa, such as reptiles and birds. We used immunolocalization of SYCP3, the protein of the lateral element of the synaptonemal complex (SC), centromere proteins and the mismatch-repair protein MLH1, which is associated with the recombination nodules, at the synaptonemal complex spreads of prophase oocytes of two tern species, black tern (Chlidonias niger) and common tern (Sterna hirundo). We first described the karyotype of Ch. niger (2n = 74, FN= 94) and identified suggestive rearrangements by which its karyotype differs from that of S. hirundo (2n = 68, FN = 90). We found that these species significantly differed by the numbers of the MLH1 foci per cell (Ch. niger: 53.0±4.2; S. hirundo: 44.1±5.0). We showed that the difference in the crossover numbers per cell was determined by the difference in the SC length (total and of individual bivalents) and by chromosomal rearrangements, which also influenced the distributions of crossover sites along the chromosomes. The difference in recombination patterns was higher between the rearranged homeologues than between the non-rearranged ones. We investigated the synaptic patterns of the heteromor phic Z and W chromosomes, localized the pseudoautosomal regions and estimated their lengths. In spite of several autosomal rearrangements, which differentiate these species, the structure and synaptic patterns of the sex chromosomes have not changed over 9 MY, which have passed since the moment of divergence between the genera Sterna and Chlidonias.

Mobile genetic elements (MGE) play an important role in genome structure and gene expression changes. All types of MGE are subdivided to two classes – retrotransposons and DNA-transposons. MGE were found in genomes of all main taxa of marine invertebrates and are represented by both classes. MGEs were found in genomes of Cnidaria species: Aurelia aurita, Acropora millepora, A. palmata, A. digitifera, Nematostella vectensis. MGE were studied in two flatworms (Platyhelminthes) species - Stylochus zebra and Bdelloura candida. In Annelida taxa, MGE were studied for Capitella capitata species. Echinodermata were represented in the review study by species Strongylocentrotus purpuratus, S. franciscanus, S. drobachiensis, Tripneustes gratilla, Lytechinus pictus, L. variegatus, Arbacia punctulata, and Eucidaris tribuloides. A quantity of MGE in Mollusca was studied for following species: Mytilus galloprovincialis, Chione cancellata, Crassostrea gigas, C. virginica, Anadara trapezia, Aplysia californica, Gibbula cineraria, Littorina littorea, and L. saxatilis. The type of Arthropoda is the most studied for MGE presence. MGE presence was studied for following Arthropoda species: Bythograea thermydron, Ventiella sulfuris, Maia brachydactila, Cancer pagurus, Pachygrapsus marmoratus, Penaeus monodon, P. vannamei, Litopenaeus stylirostris, Agononida laurentae, Galathea squamifera, Munida acantha, M. thoe, M. gregaria, M. zebra, Munidopsis recta, Eumunida annulosa, E. sternomaculata, and Rimicaris exoculata. A part of Chordata taxon, which is not included in Vertebrata subtupe, was studied too. This part was represented in the review by species Ciona intestinalis, Oikopleura dioica, and Branchiostoma floridae. A diversity of MGEs and their characters and its role in ontogenesis, in evolution and in changes of functions of genes and genomes were discussed.