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Hybridization between wild animals and feral individuals from closely related domestic species can occur when they share the same habitat. Such events are generally regarded as a threat to the genetic integrity and survival of established wild populations. The aim of this study is to confirm a hybridization between European mouflon and feral sheep on the Adriatic island Dugi Otok, where a group of individuals phenotypically indicative of a possible introgression was photographed. Using an ovine medium-density SNP array genotypes, we provided genetic evidence of recent gene admixture between the two species. The ADMIXTURE analysis suggests that two hybrid individuals had 82.2% and 94.1% of their ancestry attributable to feral sheep, respectively, with the rest of the mouflon in origin. NEWHYBRIDS analysis estimated the combined probabilities for the putative hybrid individuals belonging to one of the hybrid classes at 87.0% and 90.1%, respectively. The main phenotypic differences in the hybrids were observed in the shape of the horns, a stronger horn circumference than in the mouflon and weaker than for the sheep, pronounced horn rings, a shorter tail, and intermediate color. We therefore recommend constant monitoring of the purity of the mouflon population to maintain its genetic integrity. In addition, all feral sheep should be removed from the wild, and released sheep raised in semi-wild conditions should be better controlled.

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Reproduction of water frog hybrids Pelophylax esculentus (Pelophylax ridibundus x Pelophylax lessonae) is associated with hemiclonal reproduction and backcrossing. The hemiclonal mode of reproduction occurs within P. esculentus allodiploids. In this case, the unrecombined genome of one parental species is transmitted to the offspring after premeiotic elimination of the chromosome set of the second parental species. Usually, the chromosome set of P. lessonae is eliminated, and the altered genome of P. ridibundus is passed on to the progeny. The hemiclonal inheritance within diploid Pelophylax esculentus hybrids may be accompanied by certain aberrations of premeiotic elimination. As a result, the formation of P. ridibundus specimens with introgressions of the P. lessonae genetic material, or the formation of recombinant hybrids occurs, depending on which of the parental species backcrossing takes place. The aim of our study is to describe the aberration of premeiotic elimination within the water frog P. esculentus complex detected by the nuclear gene Ldh-B inheritance, with an attempt to find out the causes of this phenomenon. It has been established that aberrations of premeiotic elimination are widespread, but only within populations of water frog from the river system of Upper Dnieper within Ukraine. The highest level of introgression takes place in the water frog populations within Kiev metropolis under conditions of expressed anthropogenization, while the maximum frequency of recombinants was detected within populations from the basin of Desna River, that has preserved native ecosystems. It was demonstrated that the frequency of premeiotic aberrations does not correlate with the intensity of interspecific water frog hybridization. Populations with introgressions are more common than populations with recombinants, however, within the latter, the frequency of recombination events is higher. The primary factor of gametogenesis aberrations, most likely, is the genetic characteristics of the local populations of parental species, since unambiguous explanations of this phenomenon based on the action of environmental stress (pollution of water systems) are not obvious.

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BACKGROUND: Cottonseed oil is a promising edible plant oil with abundant unsaturated fatty acids. However, few studies have been conducted to explore the characteristics of cottonseed oil. The molecular mechanism of cottonseed oil accumulation remains unclear. RESULTS: In the present study, we conducted comparative transcriptome and weighted gene co-expression network (WGCNA) analysis for two G. hirsutum materials with significant difference in cottonseed oil content. Results showed that, between the high oil genotype 6053 (H6053) and the low oil genotype 2052 (L2052), a total of 412, 507, 1,121, 1,953, and 2,019 differentially expressed genes (DEGs) were detected at 10, 15, 20, 25, and 30 DPA, respectively. Remarkably, a large number of the down-regulated DEGs were enriched in the phenylalanine metabolic processes. Investigation into the dynamic changes of expression profiling of genes associated with both phenylalanine metabolism and oil biosynthesis has shed light on a significant competitive relationship in substrate allocation during cottonseed development. Additionally, the WGCNA analysis of all DEGs identified eight distinct modules, one of which includes GhPXN1, a gene closely associated with oil accumulation. Through phylogenetic analysis, we hypothesized that GhPXN1 in G. hirsutum might have been introgressed from G. arboreum. Overexpression of the GhPXN1 gene in tobacco leaf suggested a significant reduction in oil content compared to the empty-vector transformants. Furthermore, ten other crucial oil candidate genes identified in this study were also validated using quantitative real-time PCR (qRT-PCR). CONCLUSIONS: Overall, this study enhances our comprehension of the molecular mechanisms underlying cottonseed oil accumulation.

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Crop wild relatives (CWRs), landraces and exotic germplasm are important sources of genetic variability, alien alleles, and useful crop traits that can help mitigate a plethora of abiotic and biotic stresses and crop yield reduction arising due to global climatic changes. In the pulse crop genus Lens, the cultivated varieties have a narrow genetic base due to recurrent selections, genetic bottleneck and linkage drag. The collection and characterization of wild Lens germplasm resources have offered new avenues for the genetic improvement and development of stress-tolerant, climate-resilient lentil varieties with sustainable yield gains to meet future food and nutritional requirements. Most of the lentil breeding traits such as high-yield, adaptation to abiotic stresses and resistance to diseases are quantitative and require the identification of quantitative trait loci (QTLs) for marker assisted selection and breeding. Advances in genetic diversity studies, genome mapping and advanced high-throughput sequencing technologies have helped identify many stress-responsive adaptive genes, quantitative trait loci (QTLs) and other useful crop traits in the CWRs. The recent integration of genomics technologies with plant breeding has resulted in the generation of dense genomic linkage maps, massive global genotyping, large transcriptomic datasets, single nucleotide polymorphisms (SNPs), expressed sequence tags (ESTs) that have advanced lentil genomic research substantially and allowed for the identification of QTLs for marker-assisted selection (MAS) and breeding. Assembly of lentil and its wild species genomes (~4Gbp) opens up newer possibilities for understanding genomic architecture and evolution of this important legume crop. This review highlights the recent strides in the characterization of wild genetic resources for useful alleles, development of high-density genetic maps, high-resolution QTL mapping, genome-wide studies, MAS, genomic selections, new databases and genome assemblies in traditionally bred genus Lens for future crop improvement amidst the impending global climate change.

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Though the karst regions in south and southwest China are plant diversity hotspots, our understanding of the phylogeography and evolutionary history of the plants there remains limited. The genus Heteroplexis (Asteraceae) is one of the typical representative plants isolated by karst habitat islands, and is also an endangered and endemic plant to China. In this study, species-level phylogeographic analysis of the genus Heteroplexis was conducted using restriction site-associated DNA sequencing (RADseq). The genetic structure showed a clear phylogeographic structure consistent with the current species boundaries in the H. microcephala, H. incana, H. vernonioides, H. sericophylla, and H. impressinervia. The significant global (R = 0.37, P < 0.01) and regional (R = 0.650.95, P < 0.05) isolation by distance (IBD) signals among species indicate strong geographic isolation in the karst mountains, which may result in chronically restricted gene flow and increased genetic drift and differentiation. Furthermore, the phylogeographic structure of Heteroplexis suggested a southward migration since the last glacial period. Demographic analysis revealed the karst mountains as a refuge for Heteroplexis species. Finally, both Treemix and ABBA-BABA statistic detected significant historical gene flow between species. Significant historical gene flow and long-term stability of effective population size (Ne) together explain the high genome-wide genetic diversity among species (π = 0.05370.0838). However, the recent collapse of Ne, widespread inbreeding within populations, and restricted contemporary gene flow suggest that Heteroplexis species are probably facing a high risk of genetic diversity loss. Our results help to understand the evolutionary history of karst plants and guide conservation.

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A marker-assisted backcrossing program initiated to transfer leaf rust resistance gene LrTrk from Triticum turgidum cv. Trinakria to hexaploid wheat variety HD2932 cotransferred a stripe rust resistance gene, YrTrk, along with LrTrk. The cross of hexaploid recurrent parent HD2932 with tetraploid donor parent Trinakria produced pentaploid F1 plants. F1s were backcrossed with recurrent parent HD2932 to produce BC1F1 generation. Foreground and background selection was conducted in each backcross generation to identify plants for backcrossing or selfing. While foreground selection for LrTrk was carried out with linked and validated molecular marker Xgwm234, for background selection, 86 polymorphic SSR markers from the A and B genomes were used. Single selected plants from BC1F1 and BC2F1 generations backcrossed and selfed to produce BC2F1and BC2F2 generations, respectively. Background selection resulted in 83.72%, 91.86%, and 98.25% of RPG recovery in BC1F1, BC2F1, and BC2F2 generations, respectively. A total of 27 plants with LrTrk in homozygous state were identified in BC2F2 generation and selfed to produce 27 BC2F3 NILs. All the NILs were tested for leaf and stripe rust resistance at the seedling stage using seven Puccinia triticina and one Puccinia striiformis f.sp. tritici rust pathotypes. All the 27 NILs were found to be resistant to both leaf and stripe rust pathotypes. So, these NILs are designated to carry leaf and stripe rust resistance genes LrTrk/YrTrk.

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Leaf rust is one of the most significant diseases of wheat worldwide. In Argentina, it is one of the main reasons for variety replacement that becomes susceptible after large-scale use. Some varieties showed durable resistance to this disease, including Buck Manantial and Sinvalocho MA. RILs (Recombinant Inbred Lines) were developed for each of these varieties and used in genetics studies to identify components of resistance, both in greenhouse inoculations using leaf rust races, and in field evaluations under natural population infections. In Buck Manantial, the APR gene LrBMP1 was associated with resistance in field tests. In crosses involving Sinvalocho MA, four genes were previously identified and associated with resistance in field testing: APR (Adult Plant Resistance) gene LrSV1, the APR genetic system LrSV2 + LrcSV2 and the ASR (All Stage Resistance) gene LrG6. Using backcrosses, LrBMP1 was introgressed in four commercial susceptible varieties and LrSV1, LrSV2 + LrcSV2 and LrG6 were simultaneously introgressed in three susceptible commercial varieties. The use of molecular markers for recurrent parent background selection allowed us to select resistant lines with more than 80% similarity to commercial varieties. Additionally, progress towards positional cloning of the genetic system LrSV2 + LrcSV2 for leaf rust APR is reported.

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Animal domestication is the process of changing wild animals into domesticated animals that can be kept stably for a long period of time. As the content of the Neolithic agricultural revolution, domestication is one of the important milestones of the progress of human civilization. Due to the close relationship between humans and animals, domestication has not only changed the wild state of animals, but also changed the habits and historical processes of human beings. The key question on animal domestication research include who is the ancestors of the domesticated animals were, the changes produced by domestication, and the time and place of domestication. Due to the advances in high-throughput genomic technologies and correspondence analysis methods, animal domestication is generally studied at the population level. Here we discuss the research content of animal domestication under population genetics, including population history, selection signals, as well as gene introgression, and we highlight two new expand contents, namely, dating the initial time of gene selection and the time of gene introgression. Finally, we summarize the recent research progress of major domesticated including pig, chicken, sheep and goat. These advances provide a new insights and perspective for the research on the animal domestication.

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A near-isogenic line (NIL) of the Indian wheat variety HD2733, carrying an introgressed Lr24/Sr24 genomic region was used for studying the effect of this introgression on quality traits. Data on the grain yield and 21 quality traits were recorded in this NIL and its recurrent parent (RP), both of which were grown in a randomized block design for two consecutive years. The statistical analysis revealed that grain yield was on par between the NIL and the RP. The NIL and its RP were both hard grained but the NIL showed a grain hardness index reduced by 9.7%. However, quality traits such as grain weight, protein content, sedimentation value, gluten traits, and solvent retention capacity were significantly higher in the NIL. The NIL also showed an increase in dough stability, a lower degree of softening and a higher farinograph quality number. These results indicated that the NIL could be utilized for hard grain, high protein and strong gluten-based products. An overall improvement in the quality of the NIL over its recurrent parent and without any yield penalty suggests that the Lr24/Sr24 genomic region could be gainfully utilized in wheat breeding for improving the industrial quality of wheat without jeopardising grain yield. The authors suggest that the improved quality of the NIL may be due to the genomic segment carried along with the Lr24/Sr24 genes. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02679-x.

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We propose a method for marker-based selection of cultivars of clonally-reproducing plant species which keeps the basic genetic architecture of a top-performing cultivar (usually a partly heterozygous genotype), with the addition of some agronomically relevant differences (such as production time, product appearance or quality), providing added value to the product or cultivation process. The method is based on selecting a) two complementary nearly-inbred lines from successive selfing generations (ideally only F2 and F3) of large size, that may generate individuals with most of their genome identical to the original cultivar but being homozygous for either of the two component haplotypes in the rest, and b) individuals with such characteristics already occurring in the F2. Option a) allows for introgressing genes from other individuals in one or both of these nearly-inbred lines. Peach, a woody-perennial, clonally-reproduced species, was chosen as a model for a proof of concept of the Resynthesis process due to its biological characteristics: self-compatibility, compact and genetically well-known genome, low recombination rates and relatively short intergeneration time (3-4 years). From 416 F2 seedlings from cultivar Sweet Dream (SD), we obtained seven individuals with 76-94% identity with SD, and selected five pairs of complementary lines with average homozygosity of the two parents ≥0.70 such that crossing would produce some individuals highly similar to SD. The application of this scheme to other species with more complex genomes or biological features, including its generalization to F1 hybrids, is discussed.

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The Awassi breed is desirable due to its resilient traits, but shows poor lean meat content on the carcass; the callipyge mutation may enhance growth and meat characteristics. The first backcross of callipyge Awassi-Rambouillet (CRAW) lambs was generated by mating Awassi ewes with heterozygous F1 (50 % Awassi and 50 % Rambouillet) rams for the callipyge mutation. A fattening trial with carriers of CLPG (CRAW), non-carriers (RAW), and Awassi (AW) ram lambs was conducted for 94 days and growth and meat characteristic parameters were recorded. Final body weight, average daily gain (ADG), feed conversion ratio, and dry matter intake, but not initial body weight, were greater in CRAW and RAW lambs as compared to AW lambs; hot and cold carcass, dressing percentage, and shoulder, rack, and loin weights were greater in CRAW vs. AW but not RAW lambs. Leg cuts were heavier in CRAW vs. both RAW and AW lambs; intermuscular and subcutaneous fat percentages were greater in CRAW as compared to AW but not RAW lambs. Non-carcass components showed kidney fat, kidney, liver and testes weights higher in CRAW lambs as compared to AW lambs, but these parameters were similar to those of RAW lambs. There were no differences in fat tail weight. Further, CRAW lambs had higher shear force and water holding capacity than RAW and AW lambs, while cooking loss was the lowest in CRAW lambs. In conclusion, the callipyge mutation with 25% Rambouillet genes can provide efficient improvements in growth and meat characteristics, with the exception of tenderness in Awassi sheep.

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AIM: This study was designed to introduce the callipyge (CLPG) and 50% of Rambouillet sheep genes to improve meat quality and quantity of Awassi (AW) sheep. MATERIALS AND METHODS: The CLPG mutation was introduced into the AW sheep through frozen semen of homozygous Rambouillet rams for the CLPG mutation. Four ram lambs from the first-generation Rambouillet callipyge Awassi (F1-RCA) and five from pure AW were recruited for a fattening trial conducted in individual pens using standard ration, following which ram lambs were slaughtered for carcass and meat evaluation. RESULTS: Final body weight, dry matter intake, average daily gain, and feed conversion ratio were significantly higher in F1-RCA than AW. Hot and cold carcass weights and the other carcass cuts' weights, except for the fat tail, were heavier in F1-RCA than AW. There was no difference in dressing percentage between the two genetic groups (p>0.05). All non-carcass components' weights, except spleen, kidney, and testis, were higher in F1-RCA. Total lean, total bone, and intermuscular fat weight were greater in F1-RCA, but bone-to-lean ratio was lower in F1-RCA when compared with AW (p<0.01). No differences (p>0.05) were observed in all meat quality parameters for muscle longissimus with the exception of pH, redness color, and tenderness that were lower (p<0.05) in F1-RCA than AW. F1-RCA lambs had larger longissimus muscle area (30.9 vs. 16.9 cm2) and less leg fat depth (11.1 vs. 17.4 mm). CONCLUSION: The implications of this research show the potential of 50% of Rambouillet genes and the CLPG mutation to improve growth and meat characteristics in AW-Rambouillet crosses and can be used further to develop a meat-type AW with improved productivity and muscle mass.

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Jatropha curcas L. (2n = 2× = 22) is increasingly attracting attention in the biodiesel industry for its oil. However, the cultivation of J. curcas L. is faced with numerous challenges unlike the cultivation of Ricinus communis L. (2n = 2× = 20), a closely related species. The generation of an intergeneric hybrid between J. curcas L. and R. communis L. was investigated. Intergeneric hybrids were produced by hand crossing. Immature embryos were rescued, in vitro, from the hybrid seeds and cultured on an enriched Murashige and Skoog (MS) medium for a month. The plantlets produced were grown in sterile peat moss in plastic pots and covered with polyethylene for 30 days, after which they were transferred into cement potted soil. The hybridity and the genuineness of the hybrids were successfully confirmed using randomly amplified polymorphic DNA (RAPD) markers. The number of branches, stem diameter, and leaf size of the F1 hybrids were similar to those of J. curcas L. while the plant height was similar to that of R. communis L. Young hybrids were treated with various concentrations (0%, 0.3%, 0.4%, and 0.5%) of colchicine to induce polyploids. The calli (JR6) treated with 0.3% colchicine recorded the highest tetraploid cell percentage (38.89%). A high tetraploid cell percentage (>50%) is significant in overcoming the problem of sterility after hybridization.

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The distribution and genetic diversity of freshwater zooplankton is understudied in the Eastern Palearctic. Here, we explored the lineage diversity and regional distribution of the genus Moina in China. Members of this genus are often keystone components of freshwater ecosystems and have been frequently subjected to toxicological and physiological studies. Four species of Moina were identified, based on morphology, in 50 of 113 Chinese water bodies examined, and their phylogenetic position was analyzed using both a mitochondrial (mitochondrial cytochrome c oxidase subunit I; COI) and a nuclear marker (the nuclear internal transcribed spacer; ITS-1). Both molecular markers identified four clades corresponding broadly to the morphological species. Mitochondrial DNA analysis showed the presence of four species complexes with eleven lineages across China, five of which were new. However, some lineages (and even individual haplotypes) were widespread in Eurasia, suggesting an ability to disperse over long distances. In contrast, a few lineages exhibited restricted distributions. The nuclear phylogeny also recognized four species of Moina within China and seven very distinct clades. Interestingly, one specimen possessing Moina cf. micrura mtDNA had ITS-1 alleles of the M. cf. brachiata clade. This discordance between mtDNA and nuclear ITS-1 phylogenies is indicative of interspecific introgression and hybridization. Additionally, our COI phylogeny showed apparent paraphyly in two Moina species groups, suggesting introgression of their mitochondrial genomes. Our data shows the regional distribution/diversity of the Moina species complex in a Eurasian context.

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Hybridisation between a domesticated species and its wild ancestor is an important conservation problem, especially if it results in the introgression of domestic gene variants into wild species. Nevertheless, the legal status of hybrids remains unregulated, partially because of the limited understanding of the hybridisation process and its consequences. The occurrence of hybridisation between grey wolves and domestic dogs is well documented from different parts of the wolf geographic range, but little is known about the frequency of hybridisation events, their causes and the genetic impact on wolf populations. We analysed 61K SNPs spanning the canid genome in wolves from across Eurasia and North America and compared that data to similar data from dogs to identify signatures of admixture. The haplotype block analysis, which included 38 autosomes and the X chromosome, indicated the presence of individuals of mixed wolf-dog ancestry in most Eurasian wolf populations, but less admixture was present in North American populations. We found evidence for male-biased introgression of dog alleles into wolf populations, but also identified a first-generation hybrid resulting from mating between a female dog and a male wolf. We found small blocks of dog ancestry in the genomes of 62% Eurasian wolves studied and melanistic individuals with no signs of recent admixed ancestry, but with a dog-derived allele at a locus linked to melanism. Consequently, these results suggest that hybridisation has been occurring in different parts of Eurasia on multiple timescales and is not solely a recent phenomenon. Nevertheless, wolf populations have maintained genetic differentiation from dogs, suggesting that hybridisation at a low frequency does not diminish distinctiveness of the wolf gene pool. However, increased hybridisation frequency may be detrimental for wolf populations, stressing the need for genetic monitoring to assess the frequency and distribution of individuals resulting from recent admixture.

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BACKGROUND: The brown planthopper (BPH), an insect species that feeds on rice plants (Oryza sativa L.), is one of the most destructive insect pests of rice. BPH can be controlled with chemical pesticides, but they are expensive in terms of the cost and environmental hazards. Hence, utilization of resistance genes in resistant varieties is considered as a more economical and eco-friendly effective method for control. RESULTS: In this study, six dominant BPH-resistance genes (Bph3, Bph14, Bph15, Bph18, Bph20 and Bph21) were introduced into an elite indica rice cultivar Jin 23B using the marker-assisted selection (MAS) method of breeding. One line combining Bph14 and Bph15 and six single gene introgression lines were used to evaluate the gene effects based on three parameters: seedling and tillering resistance of the rice genotypes, honeydew weight, and BPH survival rate. Among all improved lines, combination of Bph14 and Bph15 had the largest effect in conferring resistance to BPH. Bioassays showed that the order of the gene effects was Bph14/Bph15 > Bph15 ≥ Bph14 ≥ Bph20 ≥ Bph21 ≥ Bph3 > Bph18 > none at the rice seedling stage. The pyramided or single-gene introgression lines showed enhanced resistance relative to the control. Furthermore, field trial data demonstrated that yields of improved Jin 23B lines were similar to the control under BPH-free field conditions. CONCLUSIONS: Each of the BPH resistance genes reduced BPH growth and development, and was effective at both the seedling and tillering growth stages. These lines can be used in rice hybrid and production in China.

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Genomic data are a powerful tool for elucidating the processes involved in the evolution and divergence of species. The speciation and phylogenetic relationships among Chinese Juglans remain unclear. Here, we used results from phylogenomic and population genetic analyses, transcriptomics, Genotyping-By-Sequencing (GBS), and whole chloroplast genomes (Cp genome) data to infer processes of lineage formation among the five native Chinese species of the walnut genus (Juglans, Juglandaceae), a widespread, economically important group. We found that the processes of isolation generated diversity during glaciations, but that the recent range expansion of J. regia, probably from multiple refugia, led to hybrid formation both within and between sections of the genus. In southern China, human dispersal of J. regia brought it into contact with J. sigillata, which we determined to be an ecotype of J. regia that is now maintained as a landrace. In northern China, walnut hybridized with a distinct lineage of J. mandshurica to form J. hopeiensis, a controversial taxon (considered threatened) that our data indicate is a horticultural variety. Comparisons among whole chloroplast genomes and nuclear transcriptome analyses provided conflicting evidence for the timing of the divergence of Chinese Juglans taxa. J. cathayensis and J. mandshurica are poorly differentiated based our genomic data. Reconstruction of Juglans evolutionary history indicate that episodes of climatic variation over the past 4.5 to 33.80 million years, associated with glacial advances and retreats and population isolation, have shaped Chinese walnut demography and evolution, even in the presence of gene flow and introgression.

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Species delimitation by DNA sequence data or DNA barcoding is successful, as confirmed by the vast BOLD data base. However, the theory that would explain this fact has not been developed yet. An approach based on Barcoding Index Number (BIN), suggested in the assignment, allows delimiting of taxa of three ranks (species, genera, and families) and statistical validation with a high precision of delimiting (over 80%), as well as shows for majority of Co-1-based single gene trees good correspondence between their topology and conventional taxa content for analyzed fish species (R2 ≈ 0.84-0.98). Knowledge of deviations from these data can help to find out new taxa and improve biodiversity description. It is concluded that delimiting is successful for bulk of cases because the geographic mode of speciation prevails in nature. It takes a long time for new taxa to form in isolation, which allows accumulation of random mutations and many different nucleotide substitutions between them that can be detected by molecular markers and give unique DNA barcodes. The use of BIN approach, described here, can aid greatly in making this important question clearer especially under wider examination of other organisms.

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Group of experiments were carried out to verify possibility of gene introgression from common wheat into Aegilops. The artificial indoor crossbreed was conducted using 7 genotypes from 4 wheat relative species as female, and common wheat as male. The experiment result shows that different species has variable cross ability. Among the 4 Aegilops species, the highest cross rate is from the combination of Aegilops tauschii × Triticum aestivum (46.49% for genotype Ae42, 22.58% for Y92), the second is from Aegilops ovata × T. aestivum (14.76% for Y100, 12.11% for Ae23), the third is from Aegilops cylindrica × T. aestivum (2.23% for Ae7, 8.50% for Y145), and the lowest is from Aegilops speltoides × T. aestivum (0.19%). Hybrid embryos from different combinations have different ability of callus initiation and germination. The hybrid embryos from A. ovata/T. aestivum and Ae. tauschii/T. aestivum have a higher level of callus initiation and germination. Ae. cylindrica/T. aestivum has a middle level, while the Ae. speltoides has a lower level. The interspecific hybrids between Aegilops and common wheat have so low fertility. In back-crosses, the seed-set rate of hybrids of Ae. ovata/T. aestivum is 3.71% and 4.36% respectively back-crossed with male and female parents, while for hybrids of Ae. cylindrica/T. aestivum, they were 0 and 0.33% respectively, and for Ae. tauschii/T. aestivum, 0.33% and 0 respectively. On selfing of the hybrids, the seed-set rate is 0 (no seed set from 9750 florets) for the combination of Ae. cylindrica/T. aestivum, 0.044% (3 selfed seeds out of 6870 florets) for Ae. ovata/T. aestivum and 0 (no seed set from 7253 florets) for Ae. tauschii/T. aestivum. The research suggests that the probability of gene introgression from T. aestivum into Aegilops species is very low in nature.