Hybrid Females Research Articles

Changes in Alternative Splicing Revealed Special Metabolic Pathways Related to Heterosis of Heading Chinese Cabbage

As an important genetic improvement technique in current production practice, heterosis is widely used to enhance the productive traits of hybrid progeny from their parents. Alternative splicing (AS) analysis can be used as a method for exploring the molecular manifestations of heterosis. In our research, 16 hybrids and their parents were utilized to analyze the heterosis performance and AS events. Statistics of plant gross weight (PGW) showed that these hybrids had prominent heterosis, with the mid-parent heterosis values (MPV) ranging from 15.69% to 233.98%. Through pairwise comparison among the female parent, male parent, and hybrid, there were 2980–3205 AS events in each combination, with intron retention being the most common type followed by alternate 3’ splice site, alternative 5’ splice site, skipped exon, and mutually exclusive exon.There were 263–409 differential AS genes (DASGs) between the female parent and the hybrid, and 234–425 DASGs between the male parent and the hybrid in cross combinations. The DASGs were significantly enriched in 33 metabolic pathways in 16 cross combinations, and DASGs of different cross combinations were enriched in different metabolic pathways. Moreover, 76 DASGs in the strong heterosis combinations were identified and significantly enriched in the metabolic pathways related to amino acid metabolism. Further analysis revealed that most of these DASGs in amino acid metabolism were expressed differently in strong heterosis combinations. In addition, the expression levels of BraA06g014310.3C and BraA03g041700.3C in amino acid metabolism significantly correlated with PGW. These results could provide an index for future studies of the genetic and molecular mechanism of heterosis in hybrids.

Experimental introgression in Drosophila: Asymmetric postzygotic isolation associated with chromosomal inversions and an incompatibility locus on the X chromosome.

Interspecific gene flow (introgression) is an important source of new genetic variation, but selection against it can reinforce reproductive barriers between interbreeding species. We used an experimental approach to trace the role of chromosomal inversions and incompatibility genes in preventing introgression between two partly sympatric Drosophila virilis group species, D.flavomontana and D.montana. We backcrossed F1 hybrid females from a cross between D.flavomontana female and D.montana male with the males of the parental species for two generations and sequenced pools of parental strains and their reciprocal second generation backcross (BC2 mon and BC2 fla) females. Contrasting the observed amount of introgression (mean hybrid index, HI) in BC2 female pools along the genome to simulations under different scenarios allowed us to identify chromosomal regions of restricted and increased introgression. We found no deviation from the HI expected under a neutral null model for any chromosome for the BC2 mon pool, suggesting no evidence for genetic incompatibilities in backcrosses towards D.montana. In contrast, the BC2 fla pool showed high variation in the observed HI between different chromosomes, and massive reduction of introgression on the X chromosome (large X-effect). This observation is compatible with reduced recombination combined with at least one dominant incompatibility locus residing within the X inversion(s). Overall, our study suggests that genetic incompatibilities arising within chromosomal inversions can play an important role in speciation.

Female preferences between incipient species of Drosophila athabasca reveal divergent closed functions, epistasis, and segregation of veiled preference alleles.

Theoretical models typically assume that speciation is driven by divergence in female preference functions for secondary sexual traits. However, little is known about how these functions diverge between incipient species. This study used song playback experiments and mate choice tests to characterize female preference functions for divergent male courtship songs between two incipient species of Drosophila athabasca complex; D. athabasca (WN) and Drosophila mahican (EA). The study focused on two male song parameters: pulses per burst (PPB) and inter-pulse interval (IPI). Preference functions for PPB were open-ended and lacked species-specificity. In contrast, preference functions for IPI revealed a closed shape, with peak preferences highly divergent between species. Thus, females imposed divergent and ongoing sexual selection on male IPI. Further work demonstrated variation in peak preferences and choosiness for IPI across genetic lines, while F1 hybrid females varied extensively in their mating preferences across different heterospecific line crosses. Finally, F2 female genotypes with foreign single-copy chromosome substitutions showed little to no change in preferences until three or four chromosomes were combined: indicating strong dominance epistasis. These results suggest "veiled" or hidden segregating female preference alleles for male speciation phenotypes. This may explain the rapid speciation observed in this species complex.

Differences in morphometric characterization of female BSA hybrid chickens fed on wet fermented diet containing a combination of maggot flour (Hermetia illucens) and active digestive enzymes in ration

The present study was aimed to examine the effect of feeding fermented diet containing a combination of maggot flour and active digestive enzymes in the ration on feed consumption, weight gain and exterior appearance or morphometric parameters of female BSA hybrid chickens (BSA-HC). The present study was carried out at Field Laboratory of Animal Sciences, Department of Animal Science, University of Syiah Kuala-Banda Aceh for 90 days, starting from December 1, 2021 to March 1, 2022. The study used a completely randomized design consisting of 4 treatments which were: P0 (control: chicken fed on commercial diet), P1 (chicken fed on a wet fermented diet, 9% maggot flour and 0.5% enzyme), P2 (chicken fed on a wet fermented diet, 12% maggot flour and 1 % enzyme), and P3 (chicken fed on a wet fermented diet without maggot flour and without digestive enzymes). Each treatment was repeated 4 times and total number of chickens used in the study was 80 female hybrid chickens. The data obtained were analyzed by Analysis of Variance and it was continued with Duncan’s Multiple Test by SPSS program. The results showed that difference in a combination of maggot flour and active digestive enzymes percentage in wet fermented diet had an effect on the increased in morphometric parameters such us: thigh circumference, height, and head width of chicken until 9 weeks of chicken age. However, feeding of wet fermented diet containing maggot flour and digestive enzymes resulted the same effect on morphometric parameters as commercial diet on BSA-HC hens resulted a high efficiency feed. It was presumably due to the nutritional value contained in wet fermented diet was absorbed by part of chicken body which was supported by the development of body and digestive organs. Although a combination of maggot flour and active digestive enzymes percentage in wet fermented diet does not significantly affect the morphometric parameters, the nutritional content such as protein and energy contained in the feed increased the process of performance and growth process of female hybrid chicken which was comparable to commercial diet.

Multiple renal and liver cysts in a Siberian hybrid tiger

Polycystic kidney disease (PKD) is an inherited disease commonly reported in cats, but rarely in big cats. It is associated with formation of cysts in the kidneys. This article describes the clinical, pathology and immunohistochemistry findings of PKD in a Siberian hybrid tiger. A 16-year-old female captive Siberian hybrid tiger showed inappetence, weight loss, polyuria, and polydipsia. Within six months, its body weight and hydration status were progressively declining. Although hematology parameters were normal, serum creatinine and urea levels were elevated. Ultrasonography of the kidneys showed the presence of cysts. The animal was euthanized and necropsied, revealing multiple cysts in both kidneys and liver. These samples were subjected to histopathology using routine stain, special histochemistry, and immunohistochemistry. The cysts were lined by various types of epithelial cells. Most renal tubular epithelium showed severe vacuolar degeneration, accompanied by bacterial colonies in the renal pelvis. Masson’s trichrome stain demonstrated presence of mesenchymal stroma at the periphery of the cysts in the kidneys and liver. Immunohistochemistry showed different staining intensity of β-catenin, E-cadherin, and vimentin in the various parts of renal tubules, suggesting the involvement of epithelial-mesenchymal transformation. The tiger was diagnosed with PKD based on clinical and pathological examination. This is the first report of PKD in a tiger, potentially useful for future study in wildlife medicine and conservation.

Dynamics of cell-free DNA levels in the in vivo LPS-induced inflammation model

An increased concentration of extracellular cell free DNA (cfDNA) is a distinctive characteristic of pathologies that mainly occur in acute inflammation (myocardial infarction, sepsis, stroke, trauma). The increase of cfDNA in chronic inflammatory processes, oncological, autoimmune diseases is less significant and is mainly due to aberrant cell death processes. One of such diseases is systemic lupus erythematosus (SLE). It has recently been shown that, in addition to increased cfDNA concentration, the degree of inflammation can reflect the N/L index (neutrophil to lymphocyte ratio), being a simple and informative marker of disease activity in patients with SLE. The aim of the study was to study the dynamics of the level of cfDNA and the N/L index in the model of LPS-induced inflammatory response as observed in intact mice, and their relation to the phenotypic heterogeneity of model SLE. We used female hybrid mice (C57Bl/6xDBA/2) F1 and female DBA/2 mice at the age of 6-8 weeks. LPS of E. coli strain 111: B4 (Sigma) was injected intraperitoneally once at doses of 10 ng, 1 g and 100 g per mouse in PBS. The control group was injected with the appropriate volume of buffer. The TNF-binding domain of the variola virus CRMB protein was used as an inhibitor of TNF, which was administered 30 min before the introduction of LPS. The dynamics of the response to LPS was assessed after 4, 8, 11, 24 hours by the N/L index and the level of cfDNA; at the zero point, the parameters were determined before the introduction of LPS. A day after a single injection of LPS at a dose of 1 g/mouse, a SLE model was induced on the same hybrid mice (double intravenous administration with an interval of 6 days of spleen cells of the DBA/2 line, 60-70 106 cells each). Three months later, with proteinuria of 3 mg/ mL or more, mice were assigned to the SLEnephritis+ group, with a protein of less than 3 mg/mL, to the SLEnephritis- group. Statistical processing of the results was carried out by nonparametric statistics using the MannWhitney test. Differences were considered statistically significant at p 0.05. It was found that the change in the N/L index, as well as the change in the level of cfDNA, depends on the dose of LPS administered. It was shown that the level of cfDNA reaches its maximum after 8 and 11 hours after the introduction of LPS is reliably reduced when using the inhibitor TNF. A retrospective analysis indicates that there is a definite relationship between the response of intact mice to LPS before induction of cGVHD, and their subsequent division into variants of SLEnephritis + and SLEnephritis - in the course of disease development.

The p-ERG spatial acuity in the biomedical pig under physiological conditions

Pigs are becoming an important pre-clinical animal species for translational ophthalmology, due to similarities with humans in anatomical and physiological patterns. Different models of eye disorders have been proposed, and they are good candidates to assess biocompatibility/functionality of retinal prostheses. Electroretinography is a common tool allowing to gain information on retinal function, with several types of electroretinogram (ERG) been implemented including full field (ff-ERG), multifocal (mf-ERG) and pattern (p-ERG). p-ERG represents a valuable tool to monitor Retinal Ganglion Cells (RGCs) activity and can be used to calculate p-ERG spatial acuity. Unfortunately, scarce methodological data are available regarding recording/interpretation of p-ERG and retinal acuity in biomedical pigs yet enhancing knowledge regarding pig vision physiology will allow for more refined and responsible use of such species. Aim of this study was to record p-ERG in juvenile pigs to functionally assess visual acuity. Six female hybrid pigs underwent two p-ERG recording sessions at 16 and 19 weeks of age. Photopic ff-ERG were also recorded; optical coherence tomography (OCT) and histology were used to confirm retinal integrity. ff-ERG signals were repeatable within/across sessions. All p-ERG traces consistently displayed characterizing peaks, and the progressive decrease of amplitude in response to the increment of spatial frequency revealed the reliability of the method. Mean p-ERG spatial acuities were 5.7 ± 0.14 (16 weeks) and 6.2 ± 0.15 cpd (19 weeks). Overall, the p-ERG recordings described in the present work seem reliable and repeatable, and may represent an important tool when it comes to vision assessment in pigs.

Extracellular DNA in blood: an index of <i>in vivo</i> inflammatory response

Increased concentration of cell-free DNA (cfDNA) in the circulating blood of humans and animals is a sign of inflammatory conditions and a distinctive characteristic of various pathophysiological processes in the body. The aim of the present study was to investigate the possible role of tumor necrosis factor (TNFα) in changes of cfDNA contents in peripheral blood as a response to experimentally induced systemic inflammation.We used 40 female hybrid mice (C57Bl/6xDBA/2) F1 at the age of 6-8 weeks. The concentration of cfDNA and its individual fractions was determined using a PicoGreen fluorescent dye. The dynamics of inflammatory process was evaluated after 4, 8, 11 and 24 hours following LPS injection. A significant increase in the blood plasma cfDNA levels was shown under the action of E. coli lipopolysaccharide (LPS), along with simultaneous decreased levels of cfDNA, associated with cell surface. The ratio of cell surface-bound cfDNA to the total cfDNA contents was reduced in dose-dependent manner as early as 4 hours after LPS injection to the animals, thus allowing us to consider this ratio a characteristic sign of netosis of neutrophilic granulocytes during the development of acute inflammation. The described effects are significantly suppressed with co-injection of recombinant TNFα neutralizing protein along with LPS, whereas increased intake of neutrophils in the tissues is determined by some other factors which are not directly related to the production of this cytokine.Based on the obtained data, we proposed a following hypothesis: induction of netosis by inflammatory stimuli causes an increase in the concentration of cfDNA in blood plasma not only due to de novo emerging extracellular DNA by neutrophil netosis, but also by the release of distinct cfDNA fraction that was previously firmly bound to cell membranes in multiple body tissues under the action of proteases released during netosis.

Maintenance of pure hybridogenetic water frog populations: Genotypic variability in progeny of diploid and triploid parents.

An intriguing outcome of hybridisation is the emergence of clonally and hemiclonally reproducing hybrids, that can sustain, reproduce, and lead to the emergence of polyploid forms. However, the maintenance of diploid and polyploid hybrid complexes in natural populations remains unresolved. We selected water frogs from the Pelophylax esculentus complex to study how diploid and triploid hybrids, which reproduce hemiclonally via hybridogenesis, are maintained in natural populations. During gametogenesis in diploid hybrids, one of the parental genomes is eliminated, and the remaining genome is endoreplicated. In triploid hybrids, the single-copy genome is typically eliminated, while genome endoreplication does not occur. To investigate how diploid and triploid hybrid frogs reproduce in populations without parental species, we crossed these hybrid animals from two separate pure hybrid populations located in Poland. Using cytogenetic analysis of tadpoles that emerged from the crosses, we established which gametes were produced by parental hybrids. The majority of hybrid females and hybrid males produced one type of gamete with the P. ridibundus genome. However, in both studied populations, approximately half of the diploid and triploid hybrids simultaneously produced gametes with different genome compositions and ploidy levels, specifically, the P. ridibundus and P. lessonae genomes, as well as diploid gametes with genomes of both parental species. Triploid hybrid males and females mostly produced haploid gametes with the P. lessonae genome; however, gametes with the P. ridibundus genome have also been observed. These results suggest that not all hybrids follow the classical hybridogenetic reproduction program and reveal a significant level of alterations in the gametogenesis pathways. In addition, we found a variable survival rate of particular progeny genotypes when we crossed hybrid females with different males suggesting the important role of postzygotic barriers on the maintenance of pure hybrid systems. We suggest that the observed variability in produced gametes and the different survival rate of the progeny with certain genotypes is crucial for the existence of pure hybrid systems.

Quality Characterization of Different Parts of Broiler and Ligor Hybrid Chickens.

The quality characterization of different parts of male and female Ligor hybrid chickens was investigated and compared with those of commercial broiler. Genotypes, muscle types, and sex had effects on the composition, physicochemical, and textural properties of chicken samples. Ligor hybrid chicken contained higher percentages of protein, moisture, ash, and collagen content but lower fat content than those of commercial broiler (p < 0.05), except in the case of breast, where no significant difference in moisture and ash was observed (p ≥ 0.05). The pH in breast meat of both chickens was lower than that of thigh meat. The color (L*, a*, and b*) values of male and female chickens were not significantly different, except for the L* value of broiler chicken, which was higher in female chickens than in male chickens. Higher cooking loss and shear force were found in male Ligor hybrid chicken. A similar protein pattern was observed for the protein from the same muscle type, irrespective of sex and genotype tested. It was observed that Ligor hybrid chicken contained higher glutamic acid and aspartic acid than commercial broilers. Therefore, Ligor hybrid chicken is a promising new source of nutrition, which can be beneficial for consumers.

Neo-sex chromosome evolution shapes sex-dependent asymmetrical introgression barrier

Sex chromosomes play a special role in the evolution of reproductive barriers between species. Here we describe conflicting roles of nascent sex chromosomes on patterns of introgression in an experimental hybrid swarm. Drosophila nasuta and Drosophila albomicans are recently diverged, fully fertile sister species that have different sex chromosome systems. The fusion between an autosome (Muller CD) with the ancestral X and Y gave rise to neo-sex chromosomes in D. albomicans, while Muller CD remains unfused in D. nasuta. We found that a large block containing overlapping inversions on the neo-sex chromosome stood out as the strongest barrier to introgression. Intriguingly, the neo-sex chromosome introgression barrier is asymmetrical and sex-dependent. Female hybrids showed significant D. albomicans–biased introgression on Muller CD (neo-X excess), while males showed heterosis with excessive (neo-X, D. nasuta Muller CD) genotypes. We used a population genetic model to dissect the interplay of sex chromosome drive, heterospecific pairing incompatibility between the neo-sex chromosomes and unfused Muller CD, neo-Y disadvantage, and neo-X advantage in generating the observed sex chromosome genotypes in females and males. We show that moderate neo-Y disadvantage and D. albomicans specific meiotic drive are required to observe female-specific D. albomicans–biased introgression in this system, together with pairing incompatibility and neo-X advantage. In conclusion, this hybrid swarm between a young species pair sheds light onto the multifaceted roles of neo-sex chromosomes in a sex-dependent asymmetrical introgression barrier at a species boundary.

Age‐dependent differences in the ventilator‐induced diaphragm dysfunction (VIDD): A multi‐omics study

Introduction &amp; ObjectiveMechanical ventilation is a life‐saving intervention in patients with respiratory failure. Controlled mechanical ventilation (CMV) is the mode of mechanical ventilation used in patients with an insufficient central respiratory drive and frequently used in COVID‐19 patients ventilated in the prone position. However, CMV is also associated with negative consequences for the major respiratory muscle the diaphragm, i.e., the ventilator induced diaphragm dysfunction (VIDD). VIDD is the major factor underlying the delayed weaning from the ventilator especially in old intensive care unit (ICU) patients. The age‐related difference in mortality rate has become a major concern during the COVID‐19 pandemic. The current experimental study was undertaken to improve our understanding the mechanisms underlying age‐related differences in the response to CMV using a unique experimental ICU model allowing long‐term studies in a rat exposed CMV.Materials and MethodsYoung (7‐8 months) and old (28‐32 months) female F344 BN hybrid rats were exposed to the ICU condition for 5 days (anaesthetized, mechanically ventilated, and pharmacologically paralyzed by post‐synaptic blockade of the neuromuscular transmission). Transcriptomics (RNA‐Seq) and proteomics (Olink) analyses of the diaphragm and proteomics analysis of plasma were conducted to investigate the molecular differences between young and old rats exposed to the ICU condition.ResultsAccording to multi‐omics analyses, significant differences were observed in the diaphragm between young and old rats in response to ICU condition. In the diaphragm of young rats, CMV resulted in decreases in the biological processes related to energy metabolism and production as indicated by the downregulation of pathway like “glycolysis/gluconeogenesis”, “fatty acid metabolism”, “TCA cycle”, and “oxidative phosphorylation”, etc. On the other hand, in the diaphragm of old rats, dramatic immune and inflammatory responses were observed after CMV, as reflected in the upregulation of “Cytokine‐cytokine receptor interaction”, “TNF signaling pathway”, “IL‐17 signaling pathway”, etc. Transcriptomic results were consistent with plasma proteomics analyses, i.e., CMV induced a higher level of inflammatory factors and cytokines/chemokines in old rats.ConclusionsAfter 5‐days exposure to CMV, our multi‐omics study demonstrated age‐related inflammatory response to long‐term mechanical ventilation.Significance/ImplicationThus, CMV should be cautiously used and restricted to as short duration as possible, especially in the old patients. In the current COVID‐19 pandemic, the dramatically increased mortality in old ICU patients with COVID‐19‐associated hyperinflammation and cytokine storm need not only reflect the viral infection but may also be associated with the VIDD and hyperinflammatory responses induced by CMV per se.

The effect of the dietary inclusion of pea seeds of colored-flowered and white-flowered varieties on gastrointestinal function in turkeys.

This study investigated the effects of dietary replacement of soybean meal (SBM) with graded levels of pea seeds (PS) on the gastrointestinal function of turkeys. Seeds of 2 pea varieties, a colored-flowered variety and a white-flowered variety (CFP and WFP, respectively) were fed to 56-d-old birds for 8 wk. A total of 539 female Hybrid turkeys were allocated to 7 groups, each group consisted of 7 pens with 11 birds per pen. The experiment had a 2-factorial design, with 3 dietary inclusion levels of PS (100, 200 and 300 g/kg) and 2 pea varieties (CFP and WFP). The control group (diets without PS) was compared with CFP and WFP treatments by simple contrast analysis. In comparison with CFP seeds, WFP seeds contained 7-fold less tannins (0.67 vs. 4.66 g/kg) and less non-starch polysaccharides (NSP, 117.8 vs. 132.7 g/kg), but more trypsin inhibitors (1.34 vs. 0.98 g/kg) and starch (489 vs. 455 g/kg). A rise in the PS content of diets from 100 to 200 and 300 g/kg increased the weight of the small intestine (P = 0.031) and the dry matter (DM) content of intestinal digesta (P = 0.001), but it had no effect on the pH of digesta. Only the highest PS content differentiated the concentrations of short-chain fatty acids (SCFAs) in the small intestinal digesta (WFP > CFP, P = 0.008), whereas PS did not cause any changes in the morphological parameters of the small intestinal mucosa. The dietary inclusion of PS had no influence on the levels of acetate, butyrate, putrefactive SCFAs or total SCFAs in the cecal contents. Apart from increasing the activities of β-glucosidase (P = 0.017) and β-galactosidase (P = 0.025), pea varieties did not affect the activities of the analyzed cecal microbial enzymes. However, CFP seeds decreased the DM content (P = 0.041) and increased the pH of cecal digesta, compared with WFP seeds (P = 0.013). The results of this study, pointing to a few differences in the functional parameters of the small intestine and cecum, indicate that tannins are not a factor differentiating the suitability of CFP and WFP seeds in the nutrition of finisher turkeys. The inclusion of PS at 200 and 300 g/kg of the diet reduces the content of SBM and wheat in turkey diets, which has a positive effect on gastrointestinal function.

Genetical, Morphological, Behavioral, and Ecological Traits Support the Existence of Three Brazilian Species of the Anastrepha fraterculus Complex of Cryptic Species

Within the Neotropical genusAnastrepha, the nominal speciesAnastrepha fraterculusis widely distributed from Mexico through northern Argentina. Currently it is believed to comprises a complex of at least eight cryptic species—known as theAnastrepha fraterculuscomplex (AF complex)—three of which occur in Brazil:A. sp.1 aff.fraterculus,A. sp.2 aff.fraterculus, andA. sp.3 aff.fraterculus. In this study, we present the results of a broad integrated analysis of multiple biological attributes in samples of the three species collected in sympatric areas. Analyses of the mitotic chromosomes confirm that all of them differ in sex chromosomes, and that the relative frequency of the distinct karyotypes is associated with variation in altitude. In these sympatric areas, a single female hybrid karyotype was detected within a significant sample of individuals. Population samples were analyzed for the ribosomal transcribed spacer ITS1, confirming that the three species have specific sequence types. Observations of reproductive behavior under laboratory conditions revealed thatA. sp.1 andA. sp.2 mate early in the morning, whileA. sp.3 mates in the middle of the day. A bimodal distribution of mating time was observed in the laboratory for hybrids, obtained betweenA. sp.1 andA. sp.3. In a mating choice experiment, most of the mating pairs were homospecific. In addition, through a list of the most frequent hosts associated with geographical occurrence, a bioclimatic model of their potential distribution was generated. The set of data allowed for the construction of explanatory hypothesis about the observed geographical pattern and the differential use of host fruits. Morphometric analyses of wings clearly demonstrated differences among the three species, for both males and females. Based on a wing image of theA. fraterculus(Wiedemann, 1830) type specimen, the morphometric analysis indicated that the type specimen would correspond to a male ofA. sp.2 aff.fraterculus. The information provided by this report is not only useful for taxonomic purposes, but also reveals aspects to be considered in any reconstruction of an evolutionary scenario of theAnastrepha fraterculuscomplex.

Clonal gametogenesis is triggered by intrinsic stimuli in the hybrid’s germ cells but is dependent on sex differentiation

Interspecific hybridization may trigger the transition from sexual reproduction to asexuality, but mechanistic reasons for such a change in a hybrid's reproduction are poorly understood. Gametogenesis of many asexual hybrids involves a stage of premeiotic endoreplication (PMER), when gonial cells duplicate chromosomes and subsequent meiotic divisions involve bivalents between identical copies, leading to production of clonal gametes. Here, we investigated the triggers of PMER and whether its induction is linked to intrinsic stimuli within a hybrid's gonial cells or whether it is regulated by the surrounding gonadal tissue. We investigated gametogenesis in the Cobitis taenia hybrid complex, which involves sexually reproducing species (Cobitis elongatoides and C. taenia) as well as their hybrids, where females reproduce clonally via PMER while males are sterile. We transplanted spermatogonial stem cells (SSCs) from C. elongatoides and triploid hybrid males into embryos of sexual species and of asexual hybrid females, respectively, and observed their development in an allospecific gonadal environment. Sexual SSCs underwent regular meiosis and produced normally reduced gametes when transplanted into clonal females. On the other hand, the hybrid's SSCs lead to sterility when transplanted into sexual males but maintained their ability to undergo asexual development (PMER) and production of clonal eggs, when transplanted into sexual females. This suggests that asexual gametogenesis is under complex control when somatic gonadal tissue indirectly affects the execution of asexual development by determining the sexual differentiation of stem cells and once such cells develop to female phenotypes, hybrid germ cells trigger the PMER from their intrinsic signals.

Introgression and mating patterns between white-handed gibbons (Hylobates lar) and pileated gibbons (Hylobates pileatus) in a natural hybrid zone.

Gibbons (Family Hylobatidae) are a suitable model for exploring hybridization in pair-living primates as several species form hybrid zones. In Khao Yai National Park, Thailand, white-handed gibbons (Hylobates lar) and pileated gibbons (Hylobates pileatus) are distributed parapatrically and hybridize in a narrow zone. Their phenotypic characteristics suggest limited inter-species gene flow, although this has never been assessed. To uncover the history and degree of gene flow between the two species, we studied the genetic structure of gibbons in the hybrid zone by analyzing fecal DNA samples, phenotypic characteristics, vocalizations and individuals' social status. We determined eight autosomal single nucleotide variant (SNV) loci, and mitochondrial DNA (mtDNA) and Y-chromosomal haplotypes of 72 gibbons. We compared these markers with reference types of wild pureblood white-handed gibbons (n = 12) in Kaeng Krachan National Park and pureblood pileated gibbons (n = 4) in Khao Soi Dao Wildlife Sanctuary. Autosomal genotypic analyses confirmed the various levels of mixed ancestry for several adult gibbons with or without atypical phenotypic traits in Khao Yai National Park. In some other adult gibbons, the mixed ancestry was not detected in either autosomal SNVs or their phenotypic traits but the mtDNA. Both male and female adult hybrids formed reproductive units mainly with a phenotypic pureblood partner and many of them produced offspring. Taken together, our results suggest that once hybridization occurs, white-handed-pileated-gibbon hybrids can reproduce with either parental species and that the backcrossing and thus introgression may occur in successive generations, with no drastic changes in phenotypic appearance.

Sexual development dysgenesis in interspecific hybrids of Medaka fish

Fish are amongst vertebrates the group with the highest diversity of known sex-determining genes. Particularly, the genus Oryzias is a suitable taxon to understand how different sex determination genetic networks evolved in closely related species. Two closely related species, O. latipes and O. curvinotus, do not only share the same XX/XY sex chromosome system, but also the same male sex-determining gene, dmrt1bY. We performed whole mRNA transcriptomes and morphology analyses of the gonads of hybrids resulting from reciprocal crosses between O. latipes and O. curvinotus. XY male hybrids, presenting meiotic arrest and no production of sperm were sterile, and about 30% of the XY hybrids underwent male-to-female sex reversal. Both XX and XY hybrid females exhibited reduced fertility and developed ovotestis while aging. Transcriptome data showed that male-related genes are upregulated in the XX and XY female hybrids. The transcriptomes of both types of female and of the male gonads are characterized by upregulation of meiosis and germ cell differentiation genes. Differences in the parental species in the downstream pathways of sexual development could explain sex reversal, sterility, and the development of intersex gonads in the hybrids. We hypothesize that male-to-female sex reversal may be connected to a different development time between species at which dmrt1bY expression starts. Our results provide molecular clues for the proximate mechanisms of hybrid incompatibility and Haldane’s rule.

3-Hydroxyquinazoline derivatives, analogues of erastin, induced ferroptosis in breast cancer cells

Introduction. Early malignant tumor detection programs have significantly increased the survival rate of breast cancer patients but the results of drug therapy for this pathology are not always highly effective. Recently discovered iron-dependent cell death, ferroptosis, makes it a promising therapeutic target to reduce the recurrence rates.Objective – to study the induction of ferroptosis in breast cancer cells MCF-7 by quinazoline derivatives synthesized at the Research Institute of Experimental Diagnostics and Therapy of Tumors of the N.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of Russia and to evaluate its antitumor activity on transplanted breast carcinoma Ca-755.Materials and methods. Derivatives of 3-hydroxyquinazoline were obtained by chemical synthesis and have a purity of at least 95 %. In this study 2D cultivation of MCF7 cells, phase-contrast and fluorescence microscopy, and a model of experimental growth of breast carcinoma Ca-755 in female hybrids of immunocompetent mice F1 (C57Bl/6 × DBA/2) were used.Results. Five derivatives of 3-hydroxyquinazoline, analogues of erastine, were studied in this work. The ferroptotic cell death was identified by the level of lipid peroxidation at the concentrations of 1/3 and 1/5 IC50. The level of lipid peroxidation induced by compound 3 was comparable with the activity of erastin in MCF7 cells at both 1/3 and 1/5 of IC50, the activity of the other four quinazoline derivatives was 50–70 % of the activity of erastin. In in vivo experiments at a dose of 30 mg/kg the antitumor efficacy of the compound 3 was higher than that of erastin at the same dose.Conclusion. The data obtained suggest that quinazoline derivative 3 might be considered as a promissisng antitumor agent to treat breast cancer.

High Stability of the Epigenome in Drosophila Interspecific Hybrids.

Interspecific hybridization is often seen as a genomic stress that may lead to new gene expression patterns and deregulation of transposable elements (TEs). The understanding of expression changes in hybrids compared with parental species is essential to disentangle their putative role in speciation processes. However, to date we ignore the detailed mechanisms involved in genomic deregulation in hybrids. We studied the ovarian transcriptome and epigenome of the Drosophila buzzatii and Drosophila koepferae species together with their F1 hybrid females. We found a trend toward underexpression of genes and TE families in hybrids. The epigenome in hybrids was highly similar to the parental epigenomes and showed intermediate histone enrichments between parental species in most cases. Differential gene expression in hybrids was often associated only with changes in H3K4me3 enrichments, whereas differential TE family expression in hybrids may be associated with changes in H3K4me3, H3K9me3, or H3K27me3 enrichments. We identified specific genes and TE families, which their differential expression in comparison with the parental species was explained by their differential chromatin mark combination enrichment. Finally, cis–trans compensatory regulation could also contribute in some way to the hybrid deregulation. This work provides the first study of histone content in Drosophila interspecific hybrids and their effect on gene and TE expression deregulation.

Avian Introgression Patterns are Consistent With Haldane's Rule.

According to Haldane’s Rule, the heterogametic sex will show the greatest fitness reduction in a hybrid cross. In birds, where sex is determined by a ZW system, female hybrids are expected to experience lower fitness compared to male hybrids. This pattern has indeed been observed in several bird groups, but it is unknown whether the generality of Haldane’s Rule also extends to the molecular level. First, given the lower fitness of female hybrids, we can expect maternally inherited loci (i.e., mitochondrial and W-linked loci) to show lower introgression rates than biparentally inherited loci (i.e., autosomal loci) in females. Second, the faster evolution of Z-linked loci compared to autosomal loci and the hemizygosity of the Z-chromosome in females might speed up the accumulation of incompatible alleles on this sex chromosome, resulting in lower introgression rates for Z-linked loci than for autosomal loci. I tested these expectations by conducting a literature review which focused on studies that directly quantified introgression rates for autosomal, sex-linked, and mitochondrial loci. Although most studies reported introgression rates in line with Haldane’s Rule, it remains important to validate these genetic patterns with estimates of hybrid fitness and supporting field observations to rule out alternative explanations. Genomic data provide exciting opportunities to obtain a more fine-grained picture of introgression rates across the genome, which can consequently be linked to ecological and behavioral observations, potentially leading to novel insights into the genetic mechanisms underpinning Haldane’s Rule.