Investigation of Genetic Association Between a High Activity Variant of Cathepsin G and Risk for Basal Cell Carcinoma.

BACKGROUND/AIM: Cathepsin G (CTSG) has been identified as an inhibitor of breast, bladder, and colorectal cancers. The G allele of the N125S (A/G, rs45567233) functional polymorphism of the CTSG gene confers increased serum CTSG activity and has been associated with cardiovascular and neurovascular diseases. This study examined the possible correlation between the pathogenesis of basal cell carcinoma (BCC) and the functional polymorphism CTSG N125S. PATIENTS AND METHODS: A total of 197 DNA samples were examined, comprising 98 BCC patients and 99 control samples of Greek origin. The CTSG N125S polymorphism was molecularly genotyped using PCR amplification, followed by enzyme digestion, and agarose gel electrophoresis of the amplified DNA fragments. RESULTS: There was no statistically significant difference in the genotypic and allelic frequencies between the patient and the control groups. CONCLUSION: There is no association between the CTSG N125S polymorphism and pathogenesis of BCC.

ProSeq4: A user-friendly multiplatform program for preparation and analysis of large-scale DNA polymorphism datasets.

Preparation of DNA polymorphism datasets for analysis is an important step in evolutionary genetic and molecular ecology studies. Ever-growing dataset sizes make this step time consuming, but few convenient software tools are available to facilitate processing of large-scale datasets including thousands of sequence alignments. Here I report "processor of sequences v4" (proSeq4)-a user-friendly multiplatform software for preparation and evolutionary genetic analyses of genome- or transcriptome-scale sequence polymorphism datasets. The program has an easy-to-use graphic user interface and is designed to process and analyse many thousands of datasets. It supports over two dozen file formats, includes a flexible sequence editor and various tools for data visualization, quality control and most commonly used evolutionary genetic analyses, such as NJ-phylogeny reconstruction, DNA polymorphism analyses and coalescent simulations. Command line tools (e.g. vcf2fasta) are also provided for easier integration into bioinformatic pipelines. Apart of molecular ecology and evolution research, proSeq4 may be useful for teaching, e.g. for visual illustration of different shapes of phylogenies generated with coalescent simulations in different scenarios. ProSeq4 source code and binaries for Windows, MacOS and Ubuntu are available from https://sourceforge.net/projects/proseq/.

Genetic Variations Related to Angiotensin II Production and Risk for Basal Cell Carcinoma.

Basal cell carcinoma (BCC) is the most prevalent human neoplasm, with constantly increasing annual incidence. Despite its slow growth, BCC is locally invasive and, if left untreated, can cause severe complications, including metastasis and death. The renin-angiotensin system (RAS) plays a key role in electrolyte balance, atrial pressure, tissue development, homeostasis, and inflammation, but also in cancer development. After binding to its type 1 receptor (AT1R), angiotensin II (ANGII), the system's principal hormonal effector, regulates cancer pathways spanning from the formation of the initial cancer cell to the construction and nutrition of the tumor microenvironment, angiogenesis, proliferation, and metastasis. Although the role of RAS in the development of skin pathologies has not been widely researched, RAS-targeting antihypertensive medications have been shown to have a chemoprotective effect against BCC. Based on those findings, our group conducted a series of genetic association studies to investigate the association between common functional variations in key genes related to ANGII production (AGT, ACE, ACE2, AT1R, AT2R, and CMA1) and the risk of BCC occurrence. This review provides a summary of the current understanding of the ANGII involvement in BCC development. The reliable and easily assessed pool of genetic biomarkers may be used for predictive testing and prevention purposes in high-risk individuals.

Switchable tetraplex elements in the heterogeneous nuclear ribonucleoprotein K promoter: micro-environment dictated structural transitions of G/C rich elements.

We have elucidated the hnRNP K promoter as a hotspot for tetraplex-based molecular switches receptive to micro-environmental stimuli. We have characterised the structural features of four tetraplex-forming loci and identified them as binding sites of transcription factors. These segments form either G-quadruplex or i-motif structures, the structural dynamicity of which has been studied in depth via several biophysical techniques. The tetraplexes display high dynamicity and are influenced by both pH and KCl concentrations in vitro. The loci complementary to these sequences form additional non-canonical secondary structures. In the cellular context, the most eminent observation of this study is the binding of hnRNP K to the i-motif forming sequences in its own promoter. We are the first to report a probable transcriptional autoregulatory function of hnRNP K in coordination with higher-order DNA structures. Herein, we also report the positive interaction of the endogenous tetraplexes with Sp1, a well-known transcriptional regulator. Treatment with tetraplex-specific small molecule ligands further uncovered G-quadruplexes' functioning as repressors and i-motifs as activators in this context. Together, our findings strongly indicate the critical regulatory role of the identified tetraplex elements in the hnRNP K promoter.Communicated by Ramaswamy H. Sarma.

Physiological and Molecular Responses of Pyrus pyraster Seedlings to Salt Treatment Analyzed by miRNA and Cytochrome P450 Gene-Based Markers.

Physiological and molecular marker-based changes were studied in the tissues of two-year-old Pyrus pyraster (L.) Burgsd. seedlings under salt treatment. For 60 days, 5 mL of 100 mM NaCl solution was applied to each plant per day to a cumulative volume of 300 mL in the substrate. In response to osmotic stress, the seedlings increased their water use efficiency (WUE) on day 20 of regular NaCl application and maintained a stable net photosynthetic rate (An) per unit area. Under conditions of increasing salinity, the young plants maintained a balanced water regime of the leaf tissues (Ψwl). The seedlings invested mass to their root growth (R/S), retained a substantial portion (72%) of Na+ ions in the roots, and protected their leaves against intoxication and damage. A significant decrease in the leaf gas exchange parameters (gs, E, An) was manifested on day 60 of the experiment when the cumulative NaCl intake was 300 mL per plant. The variability in the reactions of the seedlings to salinity is related to the use of open-pollinated progeny (54 genotypes) in the experiment. Lus-miR168 showed tissue- and genotype-specific genome responses to the applied stress. Polymorphic miRNA-based loci were mostly detected in the root samples on the 20th and 35th days of the experiment. The cumulative effect of the salt treatment was reflected in the predominance of polymorphic loci in the leaves. We can confirm that miRNA-based markers represent a sensitive detection tool for plant stress response on an individual level. The screening and selection of the optimal type of miRNA for this type of research is crucial. The cytochrome P450-Based Analog (PBA) techniques were unable to detect polymorphism among the control and treated seedlings, except for the primer pair CYP2BF+R, where, in the roots of the stressed plant, insertions in the amplicons were obtained. The expression ratios of cytochrome P450 in the salt-stressed plants were higher in the roots in the case of 20/100 mL and in the leaves with higher doses. The observed physiological and molecular responses to salinity reflect the potential of P. pyraster seedlings in adaptation to osmotic and ionic stress.

Experimental detection of conformational transitions between forms of DNA: problems and prospects.

Under different conditions, the DNA double helix can take different geometric forms. Of the large number of its conformations, in addition to the "canonical" B form, the A, C, and Z forms are widely known, and the D, Hoogsteen, and X forms are less known. DNA locally takes the A, C, and Z forms in the cell, in complexes with proteins. We compare different methods for detecting non-canonical DNA conformations: X-ray, IR, and Raman spectroscopy, linear and circular dichroism in both the infrared and ultraviolet regions, as well as NMR (measurement of chemical shifts and their anisotropy, scalar and residual dipolar couplings and inter-proton distances from NOESY (nuclear Overhauser effect spectroscopy) data). We discuss the difficulties in applying these methods, the problems of theoretical interpretation of the experimental results, and the prospects for reliable identification of non-canonical DNA conformations.

Efficiency of RAPD and SCoT Markers in the Genetic Diversity Assessment of the Common Bean.

Knowledge about the genetic diversity of the available common bean germplasm can help breeders properly direct the choice of genetic material in the breeding process. The aim of the present work was to estimate the usefulness of 10 RAPD and 10 SCoT markers in genetic diversity detection among 33 common bean genotypes. Both molecular marker systems were able to generate high levels of polymorphism in the genetic material, which was supported by the relatively high polymorphic information content (PIC) values observed for the used markers. The Diversity Detection Index (DDI) and Marker Index (MI) were used to compare the effectiveness of RAPD and SCoT markers. For both techniques, high values of MI and DDI were calculated, representing their effectivity. The SCoT markers showed higher values of the parameters used (MI = 7.474, DI = 2.265) than the RAPD markers (MI = 5.323, DDI = 1.612), indicating their higher efficiency in the detection of molecular variability. Three constructed dendrograms and PCoA plots were created using RAPD and SCoT, and both methods combined confirmed sufficient separation of the bean genotypes from each other. At the same time, a higher efficiency of SCoT markers compared to RAPD markers in the detection of the genetic diversity of beans was also proven. The results may be of future interest in the choice of genetically distant material for breeding purposes.

Genetic Modulation of the Erythrocyte Phenotype Associated with Retinopathy of Prematurity-A Multicenter Portuguese Cohort Study.

The development of retinopathy of prematurity (ROP) may be influenced by anemia or a low fetal/adult hemoglobin ratio. We aimed to analyze the association between DNA methyltransferase 3 ß (DNMT3B) (rs2424913), methylenetetrahydrofolate reductase (MTHFR) (rs1801133), and lysine-specific histone demethylase 1A (KDM1A) (rs7548692) polymorphisms, erythrocyte parameters during the first week of life, and ROP. In total, 396 infants (gestational age < 32 weeks or birth weight < 1500 g) were evaluated clinically and hematologically. Genotyping was performed using a MicroChip DNA on a platform employing iPlex MassARRAY®. Multivariate regression was performed after determining risk factors for ROP using univariate regression. In the group of infants who developed ROP red blood cell distribution width (RDW), erythroblasts, and mean corpuscular volume (MCV) were higher, while mean hemoglobin and mean corpuscular hemoglobin concentration (MCHC) were lower; higher RDW was associated with KDM1A (AA), MTHFR (CC and CC + TT), KDM1A (AA) + MTHFR (CC), and KDM1A (AA) + DNMT3B (allele C); KDM1A (AA) + MTHFR (CC) were associated with higher RDW, erythroblasts, MCV, and mean corpuscular hemoglobin (MCH); higher MCV and MCH were also associated with KDM1A (AA) + MTHFR (CC) + DNMT3B (allele C). We concluded that the polymorphisms studied may influence susceptibility to ROP by modulating erythropoiesis and gene expression of the fetal/adult hemoglobin ratio.

Ionomic Parameters of Populations of Common Juniper (Juniperus communis L.) Depending on the Habitat Type.

For the study of the ionomic parameters of Juniperus communis needles, fourteen sites covering most of the territory of Lithuania and belonging to distinct habitats (coastal brown dunes covered with natural Scots pine forests (G), Juniperus communis scrubs (F), transition mires and quaking bogs (D), subcontinental moss Scots pine forests (G), and xero-thermophile fringes) were selected. Concentrations of macro-, micro-, and non-essential elements were analyzed in current-year needles, sampled in September. According to the concentrations of elements in J. communis needles, the differences between the most contrasting populations were as follows: up to 2-fold for Mg, N, K, Ca, and Zn; 2- to 7-fold for P, Na, Fe, Cu, Al, Cr, Ni, and Pb; and 26- to 31-fold for Mn and Cd. The concentrations of Cd, Cr, and Ni in needles of J. communis did not reach levels harmful for conifers. When compared to all other habitats (B, F, G, and E), the populations from transition mires and quaking bogs (D) had significantly lower concentrations of main nutritional elements N (12176 µg/g d. m.), P (1054 µg/g d. m.), and K (2916 µg/g d. m.). In Juniperus communis scrubs (F), a habitat protected by EUNIS, the concentration of K in the needles was highest, while Zn and Cu concentrations were the lowest. Principal component (PC) analyses using concentrations of 15 elements as variables for the discrimination of populations or habitats allowed authors to distinguish F and B habitats from the E habitat (PC1) and F and D habitats from the G habitat (PC2). Discriminating between populations, the most important variables were concentrations of P, N, Mg, Ca, Cu, and K. Discriminating between habitats, the important variables were concentrations of N and P.

Tubulin-Based Polymorphism (TBP) in Plant Genotyping.

Tubulin-based polymorphism (TBP) is an intron length polymorphism (ILP) method widely applicable to any plant species and particularly suitable for a first and rapid classification of any plant genome. It is based on the selective, polymerase chain reaction (PCR)-based amplification of the two introns present at conserved positions within the coding sequences of plant ß-tubulin genes. Amplification releases a simple yet distinctive genomic profile.

Genetic variability analysis of Russian cultivars of ryegrass (Lolium) based on SCoT markers.

BACKGROUND: Ryegrass is a promising crop for the development of meadow farming in the world. More than 1000 cultivated varieties widely used in feed production have been developed, based on the main species - perennial ryegrass (Lolium perenne L.) and annual one (Lolium multiflorum Lam.). Development and implementation of the modern methods of plant varietal and species identification are of great importance. In recent years, molecular markers have been successfully used for these purposes, which increase the accuracy of the breeding material evaluation at a significant reduction of time and labor costs. The aim of this study was to assess the discriminatory potential of the new SCoT marking technique for the identification of Russian perennial (Lolium perenne L.) and annual (Lolium multiflorum Lam.) ryegrass varieties. RESULTS: Out of the total number of the tested SCoT-primers, 8 polymorphic ones were selected, which demonstrates the high stability and reproducibly amplified DNA fragments. These primers generated 107 PCR products, where 37 were found to be polymorphic. The average number of amplicons per primer was 13. The size of the PCR products varied from 349 to 2718 bp (see Table 3). The polymorphic ratio of the tested markers was 30.8%. The marker SCoT-06 was characterized by the maximum number of PCR products and the highest level of polymorphism (50%). The effective number of alleles (ne) ranged from 1.35 to 1.58 with a mean of 1.48 per locus. The average value of the PIC and Shannon index (I) were 0.35 and 0.46, respectively. The unique PCR fragments were revealed for the identification of tested varieties. Analysis of molecular variance (AMOVA) showed that the level of genetic diversity between ryegrass species (59%) was more than between varieties within a species (41%). Based on binary matrix data, clustering and PCoA analysis (see Figs. 1 and 2) of the samples were carried out that divided them into two groups according to species. CONCLUSIONS: We found a set of markers that can be useful tools for ryegrass varieties identification. The level of intravarietal polymorphism turned out to be higher than the differences between varieties because of the possible significant heterogeneity of the varietal material. The information obtained can be used in breeding programs to create improved ryegrass varieties adapted to Russian climatic conditions.

SNP and DNA methylation analyses of a monozygotic twins discordant for complete endocardial cushion defect: a case report.

The exact cause of complete endocardial cushion defect (ECD) is still unknown. This report describes a unique pair of monozygotic twins (MZ twins) discordant for ECD. The chromosome karyotyping analysis revealed normal karyotype of 46, XY, 16qh+ and mat in both MZ twins. A genome-wide analysis of DNA using the Affymetrix SNP 6.0 revealed identical genotyping of single nucleotide polymorphisms (SNPs) and copy number variations (CNVs). An extensive methylation assay was carried out by NimbleGen 3 × 720 K CpG Island Plus RefSeq Promoter Arrays to analyze the potential epigenetic differences. The DNA methylation profiles of the affected twin seemed increased compared with that of the unaffected twin. However, further validation of Notch1 promoter hypermethylation and six top-ranked differentially methylated CpG sites by sodium bisulfate modification and methylation-specific PCR, failed to reveal consistent methylation differences between the twins. Other relevant factors, such as heritability and penetrance of the condition that place the MZ twins near to a threshold for ECD or variations in local epigenetic events in the twins' heart tissues, are probably responsible for the phenotypic discordance.

The UGT1A9*22 genotype identifies a high-risk group for irinotecan toxicity among gastric cancer patients.

Several studies have shown associations between irinotecan toxicity and UGT1A genetic variations in colorectal and lung cancer, but only limited data are available for gastric cancer patients. We evaluated the frequencies of UGT1A polymorphisms and their relationship with clinicopathologic parameters in 382 Korean gastric cancer patients. Polymorphisms of UGT1A1*6, UGT1A1*27, UGT1A1*28, UGT1A1*60, UGT1A7*2, UGT1A7*3, and UGT1A9*22 were genotyped by direct sequencing. In 98 patients treated with irinotecan-containing regimens, toxicity and response were compared according to the genotype. The UGT1A1*6 and UGT1A9*22 genotypes showed a higher prevalence in Korean gastric cancer patients, while the prevalence of the UG1A1*28 polymorphism was lower than in normal Koreans, as has been found in other studies of Asian populations. The incidence of severe diarrhea after irinotecan-containing treatment was more common in patients with the UGT1A1*6, UGT1A7*3, and UGT1A9*22 polymorphisms than in controls. The presence of the UGT1A1*6 allele also showed a significant association with grade III-IV neutropenia. Upon haplotype and diplotype analyses, almost every patient bearing the UGT1A1*6 or UGT1A7*3 variant also had the UGT1A9*22 polymorphism, and all severe manifestations of UGT1A polymorphism-associated toxicity were related to the UGT1A9*22 polymorphism. By genotyping UGT1A9*22 polymorphisms, we could identify high-risk gastric cancer patients receiving irinotecan-containing chemotherapy, who would experience severe toxicity. When treating high-risk patients with the UGT1A9*22 polymorphism, clinicians should closely monitor them for signs of severe toxicity such as intense diarrhea or neutropenia.

Comparative Genomics of the Waterfowl Innate Immune System.

Animal species differ considerably in their ability to fight off infections. Finding the genetic basis of these differences is not easy, as the immune response is comprised of a complex network of proteins that interact with one another to defend the body against infection. Here, we used population- and comparative genomics to study the evolutionary forces acting on the innate immune system in natural hosts of the avian influenza virus (AIV). For this purpose, we used a combination of hybrid capture, next- generation sequencing and published genomes to examine genetic diversity, divergence, and signatures of selection in 127 innate immune genes at a micro- and macroevolutionary time scale in 26 species of waterfowl. We show across multiple immune pathways (AIV-, toll-like-, and RIG-I -like receptors signalling pathways) that genes involved genes in pathogen detection (i.e., toll-like receptors) and direct pathogen inhibition (i.e., antimicrobial peptides and interferon-stimulated genes), as well as host proteins targeted by viral antagonist proteins (i.e., mitochondrial antiviral-signaling protein, [MAVS]) are more likely to be polymorphic, genetically divergent, and under positive selection than other innate immune genes. Our results demonstrate that selective forces vary across innate immune signaling signalling pathways in waterfowl, and we present candidate genes that may contribute to differences in susceptibility and resistance to infectious diseases in wild birds, and that may be manipulated by viruses. Our findings improve our understanding of the interplay between host genetics and pathogens, and offer the opportunity for new insights into pathogenesis and potential drug targets.

The A allele of the rs759853 single nucleotide polymorphism in the AKR1B1 gene confers risk for diabetic kidney disease in patients with type 2 diabetes from a Brazilian population

ABSTRACT Objective: The AKR1B1 gene encodes an enzyme that catalyzes the reduction of glucose into sorbitol. Chronic hyperglycemia in patients with diabetes mellitus (DM) leads to increased AKR1B1 affinity for glucose and, consequently, sorbitol accumulation. Elevated sorbitol increases oxidative stress, which is one of the main pathways related to chronic complications of diabetes, including diabetic kidney disease (DKD). Accordingly, some studies have suggested the rs759853 polymorphism in the AKR1B1 gene is associated with DKD; however, findings are still contradictory. The aim was to investigate the association of the rs759853 polymorphism in the AKR1B1 gene and DKD. Materials and methods: The sample comprised 695 patients with type 2 DM (T2DM) and DKD (cases) and 310 patients with T2DM of more than 10 years' duration, but no DKD (controls). The polymorphism was genotyped by real-time PCR. Results: Allelic and genotype frequencies of this polymorphism did not differ significantly between groups. However, the A/A genotype was associated with risk for DKD after adjustment for gender, triglycerides, BMI, presence of hypertension and diabetic retinopathy, and duration of DM, under both recessive (P = 0.048) and additive (P = 0.037) inheritance models. Conclusion: Our data suggest an association between the AKR1B1 rs759853A/A genotype and risk for DKD in Brazilians T2DM patients.

The A allele of the rs759853 single nucleotide polymorphism in the AKR1B1 gene confers risk for diabetic kidney disease in patients with type 2 diabetes from a Brazilian population.

OBJECTIVE: The AKR1B1 gene encodes an enzyme that catalyzes the reduction of glucose into sorbitol. Chronic hyperglycemia in patients with diabetes mellitus (DM) leads to increased AKR1B1 affinity for glucose and, consequently, sorbitol accumulation. Elevated sorbitol increases oxidative stress, which is one of the main pathways related to chronic complications of diabetes, including diabetic kidney disease (DKD). Accordingly, some studies have suggested the rs759853 polymorphism in the AKR1B1 gene is associated with DKD; however, findings are still contradictory. The aim was to investigate the association of the rs759853 polymorphism in the AKR1B1 gene and DKD. METHODS: The sample comprised 695 patients with type 2 DM (T2DM) and DKD (cases) and 310 patients with T2DM of more than 10 years' duration, but no DKD (controls). The polymorphism was genotyped by real-time PCR. RESULTS: Allelic and genotype frequencies of this polymorphism did not differ significantly between groups. However, the A/A genotype was associated with risk for DKD after adjustment for gender, triglycerides, BMI, presence of hypertension and diabetic retinopathy, and duration of DM, under both recessive (P = 0.048) and additive (P = 0.037) inheritance models. CONCLUSION: Our data suggest an association between the AKR1B1 rs759853A/A genotype and risk for DKD in Brazilians T2DM patients.

The Development of New Species-Specific Molecular Markers Based on 5S rDNA in Elaeagnus L. Species.

The Elaeagnus L. species are trees and bushes that mainly grow in temperate zones of Western Europe; Minor, Central, and Southeast Asia; the Far East; and North America. Some species are used as fruit or ornamental plants and have economic value. Problems with the identification of species in the Elaeagnus genus by molecular genetical methods arise in the study of populations, systematics, breeding, and other areas of plant science and practice. Recently, the polymorphism of 5S ribosomal DNA non-transcribed spacers (5S rDNA NTSs) in Elaeagnaceae Adans. has been described. The results were used in our study as a basis for development of new species-specific molecular markers for some members of the Elaeagnus genus. The author's method was applied for finding regions that were potentially applicable for species-specific primer design. As a result, some species-specific molecular markers were developed for Elaeagnus angustifolia L., E. commutata Bernh., E. pungens Thunb., and E. multiflora Thunb. These markers were tested in a range of samples and showed the presence of amplified fragments in lanes of the marked species only. Samples of other species showed no amplifications. Thus, the developed markers may be useful for the species identification of the studied Elaeagnus plants in botanical, dendrological, and genetic research (especially in a leafless period of year), as well as in breeding and hybridization experiments.

Comparative binding studies on the interaction of the indoloquinoline alkaloid cryptolepine with the B and the non-canonical protonated form of DNA: A spectroscopic insight.

BACKGROUND: Low pH induced nucleic acid polymorphism and the interaction of naturally occurring small molecules with different polymorphic forms of DNA have been the focus in developing new drugs. Recent studies have revealed that low pH plays an active role in growth and development of cancer cells. Our target is to find whether and how the indoloquinoline alkaloid cryptolepine (CRP) interact with different polymorphic forms of natural DNA, in hope to explore this group of alkaloids as new therapeutics. METHODS: Multiple spectroscopic techniques that include UV-visible absorption spectrophotometry, fluorimetry, CD spectroscopy along with thermal melting studies were employed to characterize the interaction between the alkaloid cryptolepine with the B and protonated forms of DNA. RESULTS & CONCLUSIONS: Cryptolepine has been found to interact with either forms of DNA. The nature of binding is non-cooperative in both cases. Data show that the affinity of CRP to B form of DNA is relatively higher than that for the protonated form of DNA. Circular dichroic studies reveal that the alkaloid converts the left handed protonated DNA into bound right handed form. Fluorescence quenching experiments reveal that cryptolepine intercalates within the DNA base pairs. Thermal melting studies show that the alkaloid stabilises the DNA structures. GENERAL SIGNIFICANCE: Such non-B DNA structures are often present at the 'mutation hotspots' that are associated with genetic instability related diseases such as cancer. The ability of cryptolepine to interact to such non-B DNA structures makes it a useful substrate in the designing of potential chemotherapeutic agents.

Genome and Transcriptome Sequencing of Populus × sibirica Identified Sex-Associated Allele-Specific Expression of the CLC Gene.

Transcriptome sequencing of leaves, catkin axes, and flowers from male and female trees of Populus × sibirica and genome sequencing of the same plants were performed for the first time. The availability of both genome and transcriptome sequencing data enabled the identification of allele-specific expression. Such an analysis was performed for genes from the sex-determining region (SDR). P. × sibirica is an intersectional hybrid between species from sections Aigeiros (Populus nigra) and Tacamahaca (Populus laurifolia, Populus suaveolens, or Populus × moskoviensis); therefore, a significant number of heterozygous polymorphisms were identified in the SDR that allowed us to distinguish between alleles. In the SDR, both allelic variants of the TCP (T-complex protein 1 subunit gamma), CLC (Chloride channel protein CLC-c), and MET1 (DNA-methyltransferase 1) genes were expressed in females, while in males, two allelic variants were expressed for TCP and MET1 but only one allelic variant prevailed for CLC. Targeted sequencing of TCP, CLC, and MET1 regions on a representative set of trees confirmed the sex-associated allele-specific expression of the CLC gene in generative and vegetative tissues of P. × sibirica. Our study brings new knowledge on sex-associated differences in Populus species.