Structural Divergence Research Articles

The Lesson Learned from the Unique Evolutionary Story of Avirulence Gene AvrPii of Magnaporthe oryzae.

Blast, caused by Magnaporthe oryzae, is one of the most destructive diseases affecting rice production. Understanding population dynamics of the pathogen's avirulence genes is pre-required for breeding and then deploying new cultivars carrying promising resistance genes. The divergence and population structure of AvrPii was dissected in the populations of southern (Guangdong, Hunan, and Guizhou) and northern (Jilin, Liaoning, and Heilongjiang) China, via population genetic and evolutionary approaches. The evolutionary divergence between a known haplotype AvrPii-J and a novel one AvrPii-C was demonstrated by haplotype-specific amplicon-based sequencing and genetic transformation. The different avirulent performances of a set of seven haplotype-chimeric mutants suggested that the integrity of the full-length gene structures is crucial to express functionality of individual haplotypes. All the four combinations of phenotypes/genotypes were detected in the three southern populations, and only two in the northern three, suggesting that genic diversity in the southern region was higher than those in the northern one. The population structure of the AvrPii family was shaped by balancing, purifying, and positive selection pressures in the Chinese populations. The AvrPii-J was recognized as the wild type that emerged before rice domestication. Considering higher frequencies of avirulent isolates were detected in Hunan, Guizhou, and Liaoning, the cognate resistance gene Pii could be continuously used as a basic and critical resistance resource in such regions. The unique population structures of the AvrPii family found in China have significant implications for understanding how the AvrPii family has kept an artful balance and purity among its members (haplotypes) those keenly interact with Pii under gene-for-gene relationships. The lesson learned from case studies on the AvrPii family is that much attention should be paid to haplotype divergence of target gene.

Genetic Divergence and Population Structure of Xanthomonas albilineans Strains Infecting Saccharum spp. Hybrid and Saccharum officinarum.

Leaf scald caused by Xanthomonas albilineans (Xa) is a major bacterial disease in sugarcane that represents a threat to the global sugar industry. Little is known about the population structure and genetic evolution of this pathogen. In this study, 39 Xa strains were collected from 6 provinces in China. Of these strains, 15 and 24 were isolated from Saccharum spp. hybrid and S. officinarum plants, respectively. Based on multilocus sequence analysis (MLSA), with five housekeeping genes, these strains were clustered into two distinct phylogenetic groups (I and II). Group I included 26 strains from 2 host plants, Saccharum spp. hybrid and S. officinarum collected from 6 provinces, while Group II consisted of 13 strains from S. officinarum plants in the Zhejiang province. Among the 39 Xa strains, nucleotide sequence identities from 5 housekeeping genes were: ABC (99.6-100%), gyrB (99.3-100%), rpoD (98.4-100%), atpD (97.0-100%), and glnA (97.6-100%). These strains were clustered into six groups (A-F), based on the rep-PCR fingerprinting, using primers for ERIC2, BOX A1R, and (GTG)5. UPGMA and PCoA analyses revealed that group A had the most strains (24), followed by group C with 11 strains, while there was 1 strain each in groups B and D-F. Neutral tests showed that the Xa population in S. officinarum had a trend toward population expansion. Selection pressure analysis showed purification selection on five concatenated housekeeping genes from all tested strains. Significant genetic differentiation and infrequent gene flow were found between two Xa populations hosted in Saccharum spp. hybrids and S. officinarum. Altogether, these results provide evidence of obvious genetic divergence and population structures among Xa strains from China.

Description of the Wild Strain Rhizobium rosettiformans DSM26376, Reclassified under Peteryoungia rosettiformans comb.nov., for Producing Glucuronan.

Glucuronan is a polysaccharide composed of β-(1,4)-linked d-glucuronic acids having intrinsic properties and biological activities recoverable in many fields of application. Currently, the description of Sinorhyzobium meliloti M5N1CS mutant bacterial strain as the sole source of glucuronan makes it relevant to the exploration of new microorganisms producing glucuronan. In this study, the Peteryoungia rosettifformans strain (Rhizobia), was identified as a wild producer of an exopolysaccharide (RhrBR46) related to glucuronan. Structural and biochemical features, using colorimetric assays, Fourier infrared spectroscopy, nuclear magnetic resonance, high pressure size exclusion chromatography coupled to multi-angle light laser scattering, and enzymatic assays allowed the characterization of a polyglucuronic acid, having a molecular mass (Mw¯) of 1.85 × 105 Da, and being partially O-acetylated at C-2 and/or C-3 positions. The concentration of Mg2+ ions in the cultivation medium has been shown to impact the structure of RhrBR46, by reducing drastically its Mw¯ (73%) and increasing its DA (10%). Comparative structural analyses between RhrBR46 and the glucuronan from Sinorhyzobium meliloti M5N1CS strain revealed differences in terms of molecular weight, degree of acetylation (DA), and the distribution of acetylation pattern. These structural divergences of RhrBR46 might contribute to singular properties or biological activities of RhrBR46, offering new perspectives of application.

High-density SNP markers elucidate the genetic divergence and population structure of Noticiana sheep breed in the Mediterranean context.

Among livestock species, sheep have played an early major role in the Mediterranean area. Italy has a long history of sheep breeding and, despite a dramatic contraction in numbers, still raise several local populations that may represent a unique source of genetic diversity. The Noticiana is a breed of the south-eastern part of Sicily appreciated both for its dairy products and for its resistance to harsh environment. In this study, the high-density Illumina Ovine SNP600K BeadChip array was used for the first genome-wide characterization of 48 individuals of Noticiana sheep to investigate its diversity, the genome structure and the relationship within the context of worldwide and Italian breeds. Moreover, the runs of homozygosity (ROH) pattern and the pairwise FST-outliers were examined. Noticiana reported moderate levels of genetic diversity. The high percentage of short and medium length ROH segments (93% under 4 Mb) is indicative of a within breed relatedness dating back to ancient times, despite the absence of management for the mating plans and the reduced population size. In the worldwide context, the Southern Italian, Spanish and Albanian breeds overlapped in a macro cluster which also included the Noticiana sheep. The results highlighted ancestral genetic components of Noticiana shared with Comisana breed, and showed the clear separation from the other Italian sheep. This is likely the consequence of the combined effects of genetic drift, small population size and reproductive isolation. ROH islands and FST-outliers approaches in Noticiana identified genes and QTLs involved in milk and meat production, as well as related to the local adaptation, and therefore are consistent with the phenotypic traits of the studied breed. Although a wider sampling could be useful to deepen the genomic survey on Noticiana, these results represent a crucial starting point for the characterization of an important local genetic resource, with a view of supporting the local economy and preserving the biodiversity of the sheep species.

Investigating the Psychometric Properties of Sex Addiction Screening Test-revised for Persian Population

Introduction: Sexual addiction is known as a disorder that afflicts a person with difficulty in controlling or delaying sexual behaviors. To prevent social, physical, and psychological consequences, validated screening tests are needed to diagnose this disorder. One of these tests is established by Carnes with the name of sexual addiction screening test-revised (SAST-R). In this study, SAST-R has been translated and verified in the Persian language. Methods: The original screening test was translated into the Persian language and also back-translated for matching by two separate expert teams. The data was collected through an online survey of 1268 participants who were in the age range of 18 to 65 years (Mean±SD 29.44±6.90), and 56.1% and 43.9% of the population were women and men, respectively. Three questionnaires, including the SAST-R, the hypersexual behavior consequences scale, and the Connor-Davidson resilience scale as the principal, convergent, and divergent tests were administered to the participants. Results: The reliability of the test’s internal consistency (Cronbach α=0.883), split-half (Cronbach α=0.779), and Guttman (lambda coefficients were between 0.773 to 0.883) tests were used. In addition, 4 methods of content validity (sexual hyperactivity specialist approved), convergent structure validity (P<0.001, R=0.731), the validity of divergent structure (P<0.09, R=-0.132), and factor validity (comparative fit index=0.884, goodness of fit index=0.873, root mean square error of approximation=0.047) were measured and confirmed the validity of the test. Conclusion: The Persian version of SAST-R is a reliable preclinical tool to assess the severity of sexual desire in patients.

Strong selection is poorly aligned with genetic variation in Ipomoea hederacea: implications for divergence and constraint.

The multivariate evolution of populations is the result of the interactions between natural selection, drift, and the underlying genetic structure of the traits involved. Covariances among traits bias responses to selection, and the multivariate axis which describes the greatest genetic variation is expected to be aligned with patterns of divergence across populations. An exception to this expectation is when selection acts on trait combinations lacking genetic variance, which limits evolutionary change. Here we used a common garden field experiment of individuals from 57 populations of Ipomoea hederacea to characterize linear and nonlinear selection on 5 quantitative traits in the field. We then formally compare patterns of selection to previous estimates of within population genetic covariance structure (the G-matrix) and population divergence in these traits. We found that selection is poorly aligned with previous estimates of genetic covariance structure and population divergence. In addition, the trait combinations favored by selection were generally lacking genetic variation, possessing approximately 15%-30% as much genetic variation as the most variable combination of traits. Our results suggest that patterns of population divergence are likely the result of the interplay between adaptive responses, correlated responses, and selection favoring traits lacking genetic variation.

De Quervain's Disease: A Discourse on Etiology, Diagnosis, and Treatment.

Since Fritz De Quervain first postulated stenosing tenosynovitis within the radial dorsum of the wrist, much research has been conducted to provide further insights. De Quervain's Disease (DQD) is a condition that affects the tendons that control the movement of the thumb, specifically the abductor pollicis longus and extensor pollicis brevis. Numerous studies have shown that structural divergence from normal anatomy is partly related to contingency for developing DQD. Even though this condition was discovered many years ago, its exact etiology remains a subject of debate. Two schools of thought exist, one that contends an inflammatory-mediated pathway and the other degenerative changes. Substantial evidence exists for both theories, thus necessitating further studies into the etiology of DQD. Classically, Finkelstein's and Eichhoff's tests have been used as the physical examinations of choice for clinically diagnosing this condition. However, these tests have been shown to have low specificity, hence, the emergence of the wrist hyperflexion and abduction of the thumb test. Evidence also suggests that ultrasonography may become a critical diagnostic tool, especially to identify anatomical variations before invasive treatment, reducing the risk of further complications. The management of DQD is typically conservative, with escalation to steroid injections before surgery is indicated. Future research into this disease should focus on establishing a clearer picture of how anatomical variations and other pathological and occupational factors may interplay to bring about this condition. While current research has suggested possible novel approaches for diagnosing and treating DQD, more studies are required to gain greater insights into the effectiveness of these interventions.

Determining decidability: How issue salience divergence structures party systems and affects citizens

AbstractThis paper argues that issue salience divergence – the extent to which parties in a party system diverge in their allocation of salience across issues – is a key characteristic of party system decidability. Elections do not only matter in that politicians and parties with different policy positions may come to power. They can also matter if competing elites emphasize different issues. Using data from the MARPOR project and the Comparative Study of Electoral Systems, I demonstrate that voters perceive greater differences between parties when parties propose agendas that diverge with respect to issue salience. Furthermore, I demonstrate that perceptions of differences between parties mediate the effect of issue salience divergence on respondents’ satisfaction with democracy and self‐reported voter turnout. These findings indicate that salience‐based differentiation influences the quality of party systems alongside the traditional party system characteristics with important implications for public opinion and political behavior.

The persistent homology of mitochondrial ATP synthases

Relatively little is known about ATP synthase structure in protists, and the investigated ones exhibit divergent structures distinct from yeast or animals. To clarify the subunit composition of ATP synthases across all eukaryotic lineages, we used homology detection techniques and molecular modeling tools to identify an ancestral set of 17 ATP synthase subunits. Most eukaryotes possess an ATP synthase comparable to those of animals and fungi, while some have undergone drastic divergence (e.g., ciliates, myzozoans, euglenozoans). Additionally, a ∼1 billion-year-old gene fusion between ATP synthase stator subunits was identified as a synapomorphy of the SAR (Stramenopila, Alveolata, Rhizaria) supergroup (stramenopile, alveolate, rhizaria). Our comparative approach highlights the persistence of ancestral subunits even amidst major structural changes. We conclude by urging that more ATP synthase structures (e.g., from jakobids, heteroloboseans, stramenopiles, rhizarians) are needed to provide a complete picture of the evolution of the structural diversity of this ancient and essential complex.

Species boundaries within the recently diverged South American monocot‐like Eryngium (Apiaceae, Saniculoideae) based on biogeographic, climatic, morphological, and molecular data: E. cerradense, a new species from Paraguay

AbstractThe species of Eryngium with a monocot‐like habit are among the most taxonomically complex. They show low phenotypic and molecular differentiation due to their recent, rapid, and reticulate speciation during the Quaternary period. In this study, we evaluate the boundaries of the monocot‐like Eryngium regnellii and a closely related entity from the grasslands in the Cerrado of Paraguay. We integrated evidence from multiple data sources to test species delimitation: we estimated the phylogenetic position of both entities within Eryngium based on ITS nrDNA and cpDNA sequences; we carried out univariate and multivariate morphometric analyses to test statistically significant differences and to recognize morphological diagnostic characters; we also analyzed geographic distribution, habitat, and bioclimatic variables to evaluate divergence in environmental niche, and finally, we used Bayesian coalescent‐based delimitation approaches to test genetic structure. Divergence in morphology, environmental niche, and genetic structure between E. regnellii and the lineage from Paraguay support the hypothesis of evolutionary independence among these two lineages. Therefore, based on an integrative approach, we recognize and describe a new species from Paraguay: Eryngium cerradense.

Citizen Science and Natural Resource Management: A Social Network Analysis of Two Community-Based Water Monitoring Programs

In natural resource management contexts, citizen science programs often involve a diversity of actors collaborating in broad social networks. However, the characteristics and functioning of these networks has received limited attention. In this article, we demonstrate the benefits of applying social network research to citizen science practice. Through a mixed methods approach, we compare data sharing and collaboration networks of two community-based water monitoring programs in Australia. The quantitative component revealed that despite similarities in actor diversity and activities, both programs have created divergent network structures (centralized vs decentralized) corresponding to their scale of influence in environmental decision-making (regional vs local impacts). The qualitative component showed how individuals navigated their relationships and managed key tensions inherent to network functioning. This study provides new insights on the role of social networks in citizen science and concludes by recommending program leaders adopt a “networking mindset” to maximize their sphere of influence.

Comparative analysis of the organelle genomes of three Rhodiola species provide insights into their structural dynamics and sequence divergences

BackgroundPlant organelle genomes are a valuable resource for evolutionary biology research, yet their genome architectures, evolutionary patterns and environmental adaptations are poorly understood in many lineages. Rhodiola species is a type of flora mainly distributed in highland habitats, with high medicinal value. Here, we assembled the organelle genomes of three Rhodiola species (R. wallichiana, R. crenulata and R. sacra) collected from the Qinghai-Tibet plateau (QTP), and compared their genome structure, gene content, structural rearrangements, sequence transfer and sequence evolution rates.ResultsThe results demonstrated the contrasting evolutionary pattern between plastomes and mitogenomes in three Rhodiola species, with the former possessing more conserved genome structure but faster evolutionary rates of sequence, while the latter exhibiting structural diversity but slower rates of sequence evolution. Some lineage-specific features were observed in Rhodiola mitogenomes, including chromosome fission, gene loss and structural rearrangement. Repeat element analysis shows that the repeats occurring between the two chromosomes may mediate the formation of multichromosomal structure in the mitogenomes of Rhodiola, and this multichromosomal structure may have recently formed. The identification of homologous sequences between plastomes and mitogenomes reveals several unidirectional protein-coding gene transfer events from chloroplasts to mitochondria. Moreover, we found that their organelle genomes contained multiple fragments of nuclear transposable elements (TEs) and exhibited different preferences for TEs insertion type. Genome-wide scans of positive selection identified one gene matR from the mitogenome. Since the matR is crucial for plant growth and development, as well as for respiration and stress responses, our findings suggest that matR may participate in the adaptive response of Rhodiola species to environmental stress of QTP.ConclusionThe study analyzed the organelle genomes of three Rhodiola species and demonstrated the contrasting evolutionary pattern between plastomes and mitogenomes. Signals of positive selection were detected in the matR gene of Rhodiola mitogenomes, suggesting the potential role of this gene in Rhodiola adaptation to QTP. Together, the study is expected to enrich the genomic resources and provide valuable insights into the structural dynamics and sequence divergences of Rhodiola species.

Domain shuffling of a highly mutable ligand-binding fold drives adhesin generation across the bacterial kingdom.

Bacterial fibrillar adhesins are specialized extracellular polypeptides that promote the attachment of bacteria to the surfaces of other cells or materials. Adhesin-mediated interactions are critical for the establishment and persistence of stable bacterial populations within diverse environmental niches and are important determinants of virulence. The fibronectin (Fn)-binding fibrillar adhesin CshA, and its paralogue CshB, play important roles in host colonization by the oral commensal and opportunistic pathogen Streptococcus gordonii. As paralogues are often catalysts for functional diversification, we have probed the early stages of structural and functional divergence in Csh proteins by determining the X-ray crystal structure of the CshB adhesive domain NR2 and characterizing its Fn-binding properties in vitro. Despite sharing a common fold, CshB_NR2 displays an ~1.7-fold reduction in Fn-binding affinity relative to CshA_NR2. This correlates with reduced electrostatic charge in the Fn-binding cleft. Complementary bioinformatic studies reveal that homologues of CshA/B_NR2 domains are widely distributed in both Gram-positive and Gram-negative bacteria, where they are found housed within functionally cryptic multi-domain polypeptides. Our findings are consistent with the classification of Csh adhesins and their relatives as members of the recently defined polymer adhesin domain (PAD) family of bacterial proteins.

A brief history of the Jacobian

In his pioneering work, Jacobi discovered two remarkable identities related to the Jacobian. The first one asserts that the Jacobian has a divergence structure. The second one, that some vector fields involving the cofactors of the Jacobian are divergence free. We illustrate the fundamental impact of these properties on research, from the times of Jacobi to our days.

The digestive fate of beef versus plant-based burgers from bolus to stool

Ultra-processed, plant-based burgers (PB) and traditional comminuted-beef burgers (BB) share similar organoleptic characteristics, yet a knowledge gap exists in understanding how consumption of these divergent physical structures alters the lipemic response and gut microbiota. PB, comprised of highly refined ingredients, is formulated with no intact whole food structure, while BB entraps lipids throughout the myofibrillar protein network. PB presented significantly higher free fatty acid (FFA) bioaccessibility (28.2 ± 4.80 %) compared to BB (8.73 ± 0.52 %), as obtained from their FFA release profiles over digestion time after characterizing them with a modified logistic model (SLM), using the simulated TIM Gastro-Intestinal Model (TIM-1). Additionally, the rate of lipolysis, k, obtained from the SLM for PB (90% CI [0.0175, 0.0277] min−1) was higher than for BB (90% CI [0.0113, 0.0171] min−1). Using the Simulated Human Intestinal Microbial Ecosystem (SHIME®), the Firmicutes to Bacteroidetes ratio (F/B ratio) was significantly higher for PB than BB; and linear discriminant analysis effect size (LEfSe) showed Clostridium and Citrobacter were more highly represented in the microbial community for the PB feed, whereas BB feed differentially enriched Megasphaera, Bacteroides, Alistipes, and Blautia at the genus level. Additionally, short-chain fatty acid (SCFA) production was altered (p < 0.05) site-specifically in each colon vessel, which could be attributed to the available substrates and changes in microbial composition. Total SCFAs were significantly higher for PB in the ascending colon (AC) and descending colon (DC) but higher for BB only in the transverse colon (TC). This research illustrates the crucial role of meat analog physical structure in modulating nutritional aspects beyond food composition alone.

Genetic variability highlights the invasion route of the Lutzomyia longipalpis complex, the main vector of Visceral Leishmaniasis in Uruguay.

In the Americas, the sandfly Lutzomyia longipalpis is the main vector of the parasitic protozoa Leishmania infantum, the etiological agent of visceral leishmaniasis (VL). The Lu.longipalpis species complex is currently discontinuously distributed across the Neotropical region, from Mexico to the north of Argentina and Uruguay. During its continental spreading, it must have adapted to several biomes and temperature amplitudes, when founder events should have contributed to the high genetic divergence and geographical structure currently observed, reinforcing the speciation process. The first report of Lu.longipalpis in Uruguay was in 2010, calling the attention of Public Health authorities. Five years later, the parasite Le.infantum was recorded and in 2015 the first case of VL in canids was reported. Hitherto seven human cases by VL have been reported in Uruguay. Here, we publish the first DNA sequences from the mitochondrial genes ND4 and CYTB of Lu.longipalpis collected in Uruguay, and we used these molecular markers to investigate their genetic variability and population structure. We described four new ND4 haplotypes in a total of 98 (4/98) and one CYTB in a total of 77 (1/77). As expected, we were able to establish that the Lu.longipalpis collected in two localities (i.e. Salto and Bella Unión) from the north of Uruguay are closely related to the populations from neighbouring countries. We also propose that the possible route for the vector arrival to the region may have been through vegetation and forest corridors of the Uruguay River system, as well as it may have benefited from landscape modifications generated by commercial forestation. The ecological-scale processes shaping Lu.longipalpis populations, the identification of genetically homogeneous groups and the gene flow among them must be carefully investigated by using highly sensible molecular markers (i.e. genome wide SNPs) since it will help to the understanding of VL transmission and contribute to the planification of public policies on its control.

Investigating Translation Shifts and Modulation in Literary Translation: A Case Study

The present research paper examines the techniques of shifts, as proposed by Catford (1965), and modulation, as proposed by Vinay and Darbelnet (1995), adopted by Ahmed Khaled Tawfik in his translation of Palahniuk’s Fight Club. Accordingly, this paper seeks to detect the examples of modulation and the types of shifts employed, the reasons for their adoption and the most frequently used techniques of translation between English, the source language, and Arabic, the target language. The findings illustrate that all types of shifts are employed with a noteworthily frequent use of structure shifts, both optional or obligatory and argues about the structural divergence between English and Arabic. There are not so many modulation examples. It seems that Tawfik tries largely to adhere to the source text with some optional shifts so as not to appear as a translator who practises purely literal translation. This paper’s value lies in its detailed examination of Tawfik’s technique, drawing attention to the differences between English and Arabic language systems.&#x0D; &#x0D; Received: 11 December 2022 / Accepted: 11 February 2023 / Published: 5 March 2023

Rare CNVs and phenome-wide profiling highlight brain structural divergence and phenotypical convergence.

Copy number variations (CNVs) are rare genomic deletions and duplications that can affect brain and behaviour. Previous reports of CNV pleiotropy imply that they converge on shared mechanisms at some level of pathway cascades, from genes to large-scale neural circuits to the phenome. However, existing studies have primarily examined single CNV loci in small clinical cohorts. It remains unknown, for example, how distinct CNVs escalate vulnerability for the same developmental and psychiatric disorders. Here we quantitatively dissect the associations between brain organization and behavioural differentiation across 8 key CNVs. In 534 CNV carriers, we explored CNV-specific brain morphology patterns. CNVs were characteristic of disparate morphological changes involving multiple large-scale networks. We extensively annotated these CNV-associated patterns with ~1,000 lifestyle indicators through the UK Biobank resource. The resulting phenotypic profiles largely overlap and have body-wide implications, including the cardiovascular, endocrine, skeletal and nervous systems. Our population-level investigation established brain structural divergences and phenotypical convergences of CNVs, with direct relevance to major brain disorders.

Defining the separation landscape of topological domains for decoding consensus domain organization of the 3D genome.

Topologically associating domains (TADs) have emerged as basic structural and functional units of genome organization and have been determined by many computational methods from Hi-C contact maps. However, the TADs obtained by different methods vary greatly, which makes the accurate determination of TADs a challenging issue and hinders subsequent biological analyses about their organization and functions. Obvious inconsistencies among the TADs identified by different methods indeed make the statistical and biological properties of TADs overly depend on the chosen method rather than on the data. To this end, we use the consensus structural information captured by these methods to define the TAD separation landscape for decoding the consensus domain organization of the 3D genome. We show that the TAD separation landscape could be used to compare domain boundaries across multiple cell types for discovering conserved and divergent topological structures, decipher three types of boundary regions with diverse biological features, and identify consensus TADs (ConsTADs). We illustrate that these analyses could deepen our understanding of the relationships between the topological domains and chromatin states, gene expression, and DNA replication timing.

Structure Analysis of the &lt;i&gt;MatA&lt;/i&gt; Locus of Sexual Compatibility in the Edible Mushroom &lt;i&gt;Pleurotus ostreatus&lt;/i&gt;

The edible oyster mushroom Pleurotus ostreatus is one of the most cultivated species worldwide. Morphogenesis associated with the fruit bodies maturation is controlled by two unlinked loci of sexual compatibility matA and matB with multiple alleles (tetrapolar system of sexual compatibility). Quantitative analysis of the alleles of mating compatibility loci in 17 natural isolates collected in the Moscow region was performed in mon-mon (monokaryon – monokaryon) and di-mon (dikaryon – monokaryon) crossings. Four monokaryotic testers strains which were heteroallelic at both mating type loci were obtained for each of the five natural mushroom isolates by using original technique of sterile spore prints on Petri dishes and mon-mon crossing. Twelve natural isolates were crossed via di-mon mating with the four monokaryotic testers M-38. Genetic analysis of the alleles of sexual compatibility loci in 17 natural isolates revealed multiple alleles at both loci: at least 10 alleles at matA locus and eight alleles at matB locus. Structural organization analysis of the matA locus was performed in silico for homokaryotic strains PC9 and PC15 based on the genome sequencing data available at DOE Joint Genome Institute. The matA locus is proved to be of extremely divergent structure: there are one copy of the homeodomain gene hd1 and one copy of the hd2 gene in the PC9 strain, whereas the matA locus of the PC15 strain is composed by two copies of hd1.1 and hd1.2 genes (class HD1 homeodomain proteins) and one copy of hd2 gene (class HD2 proteins). Comprehensive analysis of amino acid sequences of HD1 and HD2 homeodomain proteins demonstrated that the proteins have a globular structure with the nuclear localization and contain a variable N-terminus and the more conservative DNA-binding domain with a specific conservative motif WFXNXR in the third ɑ-helix. The results approve the opinion that multiple alleles of the matA locus of sexual compatibility in basidiomycete fungi is achieved by different copies’ number of the coding hd genes within the locus, as well as by the variability of the coding gene sequences.