Search Results (88)

Polemonium L. (Polemoniaceae) is a widespread genus native to subarctic and arctic regions of the Northern Hemisphere. The taxonomy and genome relationships within Polemonium are still unclear. We analyzed genomes of three species from each Polemonium caeruleum and Polemonium pulcherrimum complex using bioinformatic analysis by RepeatExplorer2/TAREAN pipelines of next-generation sequencing data. The repeatomes of all studied species were similar in type and number of repeats. Satellite DNAs (satDNAs) demonstrated high sequence identity within the studied species. FISH chromosome mapping of 45S rDNA, 5S rDNA, and two satDNAs Pol_C 33 and Pol_C 46 allowed us to construct the species karyograms and assess the genome diversity within the P. caeruleum complex and P. pulcherrimum complex, and also confirm the taxonomic status of P. kiushianum as an independent species. Our findings demonstrate a close genomic relationship among the species from P. caeruleum and P. pulcherrimum complexes, indicating the presence of a common ancestral genome; additionally, our results provide cytogenetic evidence for the monophyletic origin of these sections and also complex evolutionary history of the genus Polemonium. The developed approach may be a valuable framework for further investigation of the chromosomal organization of karyotypes in other species of the genus Polemonium. Full article

Cardiometabolic phenotypes such as obesity and impaired insulin action are key determinants of type 2 diabetes (T2D). Growing evidence highlights the postprandial state as a critical window in metabolic regulation, where epigenetic mechanisms, particularly DNA methylation in insulin-sensitive tissues, may play pivotal roles. However, their dynamics across prandial states in subcutaneous adipose tissue (SAT) remain unclear. We analyzed genome-wide DNA methylation in paired fasting and postprandial SAT biopsies from 29 asymptomatic, drug-naïve individuals classified as controls (n = 8), prediabetes n = 9), or T2D (n = 12). Postprandial samples followed a standardized mixed-meal test. DNA methylation was quantified using the Illumina MethylationEPIC array and analyzed through the Chip Analysis Methylation Pipeline (ChAMP) pipeline. Differential methylation was more pronounced postprandially, especially in the T2D group. After adjusting for age and sex, 4599 differentially methylated CpG sites (DMCs) were identified, with increased hypermethylation in T2D. A total of 130 DMCs across 99 genes, including LCLAT1, HLA-C, ZNF714, and HOOK2, were shared by prediabetes and T2D groups. Over-representation analysis revealed 202 enriched pathways related to insulin resistance, AMPK signaling, and immune responses. Additionally, 110 Differentially Methylated Regions (DMRs), including ZNF577 and AGPAT1, were detected. These findings reveal early, prandial-dependent epigenetic alterations in SAT that precede overt dysglycemia, offering insights into personalized prevention in T2D. Full article

Tandemly repeated non-coding sequences, widely known as satellite DNAs (satDNAs), are extremely diverse and highly variable components of eukaryotic genomes. In recent years, advances in high-throughput sequencing and new bioinformatics platforms have enabled in-depth studies of all (or nearly all) tandem repeats in any genome (the satellitome), while a growing number of telomere-to-telomere assemblies facilitates their detailed mapping. Research performed on a large number of non-model plant and animal species changed significantly the “classical” view on these sequences, both in an organizational and functional sense, from ballast compacted in the form of heterochromatin to elements that are important for structuring the entire genome, as well as for its functions and evolution. The diversity of repeat families, and the complexity of their intraspecies and interspecies distribution patterns, posed new questions, urging for species-by-species comparative analyses. Here we integrate some basic features of different forms of sequences repeated in tandem and rapidly growing data evidencing extensive dispersal of satDNA sequences in euchromatin, their putative roles and evolutionary significance. Importantly, we also present and discuss various issues brought on by the use of new methodological approaches and point out potential threats to the analysis of satDNAs and satellitomes. Full article

Amaranthus L. includes valuable and promising crops of multi-purpose use, having high morphological diversity and complicated taxonomy. Their karyotypes and genomic relationships remain insufficiently studied. For the first time, a comparative repeatome analysis of Amaranthus tricolor L., Amaranthus cruentus L., and Amaranthus hypochondriacus L. was performed based on the high-throughput sequencing data obtained via bioinformatic analyses using the RepeatExplorer2/TAREAN/DANTE_LTR pipelines. Interspecific variations in the abundance of Ty1 Copia and Ty3 Gypsy retroelements, DNA transposons, and ribosomal and satellite DNA (satDNA) were detected. Based on fluorescence in situ hybridization (FISH), chromosome mapping of 45S rDNA, 5S rDNA, and satDNAs AmC9 and AmC70, and unique karyograms of A. tricolor, A. cruentus, Amaranthus paniculatus L., and A. hypochondriacus were constructed. The analysis of the interspecies genome diversity/similarity in DNA repeat contents, sequences of the identified satDNAs, and chromosome distribution patterns of the studied molecular markers indicated that these species might also share a common evolutionary ancestor. However, the genomes of A. cruentus, A. paniculatus, and A. hypochondriacus were more similar compared to A. tricolor, which aligns with the previous phylogenetic data. Our results demonstrate that cytogenomic studies might provide important data on Amaranthus species relationships elucidating taxonomy and evolution of these valuable crops. Full article

Background/Objectives: Satellite DNAs (satDNAs) are tandemly repeated sequences that play essential roles in chromosome structure, genome organization, and evolution. Despite their importance, the satellitome (the complete collection of satDNAs) of most avian lineages remains unexplored. We sought to describe the repeatome of three trogonid species, Trogon surrucura, T. melanurus, and Apaloderma vittatum with a focus on the satellitome to evaluate the general features of this lineage. Methods: Herein, we provide the first comparative characterization of the repeatome, with a particular focus on the comparative characterization of satDNAs in three trogonid species: T. surrucura, T. melanurus, and A. vittatum. Using a combination of bioinformatic pipelines and cytogenetic approaches. Results: We identified 16 satDNA families in T. surrucura, 15 in T. melanurus, and only 3 in A. vittatum. Sequence comparisons revealed that five families are shared between the two Trogon species, consistent with the library hypothesis, whereas no satDNAs were shared with A. vittatum. While both Trogon species exhibited a predominance of GC-rich repeats, A. vittatum represents the first bird described with a satellitome dominated by AT-rich satDNAs. In situ mapping in T. surrucura revealed chromosome-specific satDNAs restricted to pairs 1 and 2 and a Z-specific repeat that was strongly accumulated on its long arms, an atypical feature among birds. Conversely, the W chromosome showed a surprisingly low number of satDNAs, limited to centromeric signals. Conclusions: Our results reveal highly divergent satellitome landscapes among trogonids, characterized by lineage-specific differences in repeat composition, abundance, and chromosomal distribution. These findings support the view that satDNAs are dynamic genomic elements, whose amplification, loss, and chromosomal redistribution can influence genome architecture and play a role in avian speciation. Full article

Karyotype analysis and the investigation of chromosomal variations in Populus are challenging due to its small and morphologically similar chromosomes. Despite its utility in chromosome identification and karyotype evolutionary research, satellite DNA (satDNA) remains underutilized in Populus. In the present study, 12 satDNAs were identified from P. trichocarpa, and the copy numbers and chromosomal distributions of each satDNA were analyzed bioinformatically in the reference genomes of P. trichocarpa, P. simonii, and P. nigra. Ten satDNA probes for fluorescence in situ hybridization (FISH) were successfully developed and validated on chromosomes of P. xiaohei (poplar hybrid P. simonii × P. nigra). By integrating bioinformatic genomic satDNA distribution patterns with experimental FISH signals, we constructed a molecular karyotype of P. xiaohei. Comparative analysis revealed errors in current poplar genome assemblies. Comparative karyotype analysis of P. xiaohei and its doubled haploid (DH) lines revealed chromosomal variations in the DH lines relative to the donor tree. The results demonstrate that the newly developed satDNA probes constitute robust cytogenetic tools for detecting structural variations in Populus, while molecular karyotyping provides new insights into the genetic mechanisms underlying chromosome variations in P. xiaohei and the DH plants derived. Full article

Polemonium caeruleum L. (Polemoniaceae) is a perennial flowering plant native to Eurasia and North America, which is used as a fodder, medicinal, and ornamental plant. Many issues related to the taxonomy and origin of this valuable species still remain unclear. The intraspecific genetic variability of P. caeruleum and chromosomal organization of its genome are insufficiently studied. For the first time, we analyzed NGS genomic data of P. caeruleum using ReapeatExplorer2/TAREAN/DANTE Pipelines. In its repeatome, we identified 66.08% of Class I retrotransposons; 0.57% of Class II transposons; 0.42% of ribosomal DNA; and 0.87% of satellite DNA (six high-confident and three low-confident putative satellite DNAs). FISH chromosome mapping of seven tandem DNAs was carried out in two P. caeruleum varieties and two wild populations. Our results demonstrated the effectiveness of using satDNAs Pol_C 46 and Pol_C 33 in combination with 45S rDNA and 5S rDNA for precise chromosome identification. This approach allowed us to study intraspecific chromosomal variability and detect chromosomal rearrangements in the studied accessions of P. caeruleum, which could be related to the speciation process. These novel molecular markers are important for chromosome studies within Polemonium to clarify its taxonomy and phylogeny, and also, they expand the potential of different breeding programs. Full article

Trypanosoma cruzi is a hemoflagellate protozoan and the causative agent of Chagas disease, also known as American trypanosomiasis. Transmission occurs through the feces of triatomine insects, its biological vector. It is estimated that around 7 million people are infected across Mexico, Central America, and South America. This study aimed to identify and characterize T. cruzi isolates obtained from wild triatomine vectors collected in Aguascalientes, Mexico. Molecular identification was performed at different developmental stages—epimastigotes in culture media, metacyclic trypomastigotes in triatomine feces, and amastigotes in mouse cardiac tissue—using endpoint PCR targeting satDNA and mtCytB regions. In addition, next-generation sequencing was employed to analyze variable regions of kinetoplast DNA minicircles. The pathogenicity of the isolated and identified T. cruzi strain was assessed in a murine model, where trypomastigote stages were detected in peripheral blood and amastigote stages in muscle tissue. Molecular analyses confirmed the presence of T. cruzi across different developmental stages from wild vectors, demonstrating that the isolated wild strain possesses pathogenic potential when completing its life cycle in an experimental mammalian host, specifically BALB/c mice. Full article

Bats are great models for studying repetitive DNAs due to their compact genomes and extensive chromosomal rearrangements. Here, we investigated the repetitive DNA content of two phyllostomid bat species, Artibeus lituratus (2nn = 30♀/31♂) and Carollia perspicillata (2n = 20♀/21♂), both harboring a multiple XY₁Y₂ sex chromosome system. Satellite DNA (satDNA) libraries were isolated and characterized, revealing four and ten satDNA families in A. lituratus and C. perspicillata, respectively. These sequences, along with selected microsatellites, were in situ mapped onto chromosomes in both species and phylogenetically related taxa. SatDNAs showed strong accumulation in centromeric and subtelomeric regions, especially pericentromeric areas. Cross-species mapping with C. perspicillata-derived probes indicated terminal localization patterns in other bat species, suggesting conserved distribution. Microsatellites co-localized with 45S rDNA clusters on the neo-sex chromosomes. Additionally, genomic hybridization revealed a male-specific signal on the Y₁ chromosome, pointing to potential sex-linked repetitive regions. These findings confirm that bat genomes display relatively low amounts of repetitive DNA compared to other mammals and underscore the role of these elements in genome organization and sex chromosome evolution in phyllostomid bats. Full article

Insulin resistance is a fundamental pathophysiological mechanism contributing to the development of type 2 diabetes and metabolic syndrome. Recently, attention has focused on mitochondria’s role in glucose and lipid metabolism. Mitochondrial dysfunction is strongly associated with impaired energy metabolism and elevated oxidative stress. We investigated the mitochondrial DNA (mtDNA) copy number in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) in insulin-sensitive (IS) and insulin-resistant (IR) individuals. Twenty-seven paired adipose tissue biopsies were obtained during elective abdominal surgery. DNA and RNA were extracted, and mtDNA copy number was quantified using Real-Time PCR. We found that mtDNA content in VAT was approximately two-fold lower than in SAT. Furthermore, in IR individuals, mtDNA copy number was significantly reduced in both SAT and VAT compared to IS subjects. A strong positive correlation was observed between mtDNA content in VAT and body mass index (BMI), and a negative correlation was found with the QUICKI index. Additionally, mtDNA copy number in VAT positively correlated with the expression of several genes involved in insulin signalling, lipid metabolism, and other metabolic pathways. These findings underscore the central role of mitochondrial function in VAT in the context of metabolic disorders and suggest that targeting mitochondrial regulation in this tissue may represent a promising therapeutic approach. Full article

The genus Salvia L. (Lamiaceae) is characterized by complex taxonomy and controversial phylogeny. This genus includes about a thousand species with worldwide distribution and high ecological, structural, functional and morphological diversity. Because of their high content of essential oils, various Salvia plants are widely used in medicine, as well as in the food, perfume, cosmetic, and paint industries; they also are valuable melliferous resources. The present study reviews the taxonomic history of the genus Salvia and the phylogenetic relationships between the taxa within the subgenera Salvia, Sclarea, and Glutinaria. Among the Salvia species, three basic chromosome numbers, x = 7, x = 8, and x = 11, were most common, although other basic chromosome numbers (x = 6–19) were determined, which was probably due to events of dysploidy, aneupoidy, and/or polyploidy occurring during speciation. Recent molecular cytogenetic studies based on Next Generation Sequencing technologies have clarified the chromosomal organization of several Salvia species. The patterns of chromosome distribution of 45S rDNA, 5S rDNA, and satellite DNAs made it possible to assess their intra- and interspecific chromosome diversity. However, further cytogenetic studies are needed to characterize the chromosomes in the genomes of other Salvia species and specify the genomic relationships among them. Full article

H. pylori detection via the stool antigen test (SAT) requires 100 times more cells than nested PCR (NPCR) for a 454 bp amplicon, but is significantly more sensitive in identifying positive stool samples. To understand this contradiction, we developed an NPCR assay to amplify a shorter 148 bp segment of the 16S rRNA gene. The assay was extremely sensitive and reliable when adhering to particular rules commonly used in forensic laboratories. The SAT and NPCR for long and short amplicons were compared using stool samples from 208 gastroenterological patients, of which 27.9% were identified as positive according to the SAT and only 6.25% according to the 454 bp NPCR amplicon, but 51.0% in the short 148 bp NPCR. Among 100 asymptomatic volunteers, the prevalence was 35% in the SAT assay and 22% in the long NPCR, but as much as 66.6% of positives were determined in the short 148 bp NPCR. The specificity of the PCR product was determined via DNA sequencing, which confirmed H. pylori’s origin in all NPCR-positive samples. Apparently, the stool contains mostly short fragments of H. pylori DNA, and the most plausible explanation for the SAT/NPCR paradox is the degradation of H. pylori DNA in the digestive system. Full article

The wolf fish Hoplias malabaricus is a Neotropical species characterized by remarkable karyotypic diversity, including seven karyomorphs (KarA-G) with distinct sex chromosome systems. This study investigated the homologous XY (KarF) and XY₁Y₂ (KarG) sex chromosome systems present in this species by integrating cytogenetics and genomics to examine sex chromosomes’ composition through characterization of repeatome (satellite DNA and transposable elements) and sex-linked markers. Our analysis indicated that both karyomorphs are little differentiated in their sex chromosomes content revealed by satDNA mapping and putative sex-linked markers. Both repeatomes were mostly composed of transposable elements, but neither intra- (male versus female) nor interspecific (KarF x KarG) variations were found. In both systems, we demonstrated the occurrence of sex-specific sequences probably located on the non-recombining region of the Y chromosome supported by the accumulation of sex-specific haplotypes of HmfSat10-28/HmgSat31-28. This investigation offered valuable insights by highlighting the composition of homologous XY and XY₁Y₂ multiple sex chromosomes. Although homologous, the large Y chromosome in KarF corresponds to two separate linkage groups (Y₁ and Y₂) in KarG implying a specific meiotic arrangement involving the X chromosome in a meiotic trivalent chain. This scenario likely influenced recombination rates and, as a result, the genomic composition of these chromosomes. Full article

Satellite DNAs (satDNAs) play a crucial role in understanding chromosomal evolution and the differentiation of sex chromosomes across diverse taxa, particularly when high karyotypic diversity occurs. The Physalaemus cuvieri–Physalaemus ephippifer species complex comprises at least seven divergent lineages, each exhibiting specific karyotypic signatures. The group composed of Ph. ephippifer, Lineage 1B of ‘Ph. cuvieri’ (L1B), and a lineage resulting from their secondary contact is especially intriguing due to varying degrees of sex chromosome heteromorphism. In this study, we characterized the satellitome of Ph. ephippifer in order to identify novel satDNAs that may provide insights into chromosomal evolution, particularly concerning sex chromosomes. We identified 62 satDNAs in Ph. ephippifer, collectively accounting for approximately 10% of the genome. Notably, nine satDNA families were shared with species from distantly related clades, raising questions about their potential roles in anurans genomes. Among the seven satDNAs mapped via fluorescent in situ hybridization, PepSat3 emerged as a strong candidate for the centromeric sequence in this group. Additionally, PepSat11 and PepSat24 provided evidence supporting a translocation involving both arms of the W chromosome in Ph. ephippifer. Furthermore, a syntenic block composed of PepSat3, PcP190, and PepSat11 suggested an inversion event during the divergence of Ph. ephippifer and L1B. The variation in signal patterns of satDNAs associated with nucleolar organizer regions (NORs) highlights the complexity of NOR evolution in this species complex, which exhibits substantial diversity in this genomic region. Additionally, our findings for PepSat30-350 emphasize the importance of validating the sex-biased abundance of satDNAs. Full article

Background: The order Suliformes exhibits significant karyotype diversity, with Sula species showing a Z₁Z₁Z₂Z₂/Z₁Z₂W multiple-sex chromosome system, an uncommon occurrence in avians. Satellite DNAs (satDNAs), which consist of tandemly repeated sequences, often vary considerably even among closely related species, making them valuable markers for studying karyotypic evolution, particularly that of sex chromosome evolution. This study aims to characterize and investigate the potential role of these sequences in the karyotypic evolution of the group, with special attention to the sex chromosomes. Methods: Through characterizing satDNAs in two Suliformes species (Sula leucogaster and Nannopterum brasilianum) using BGISEQ-500 platform and bioinformatics analysis. Their chromosomal distribution was mapped by fluorescence in situ hybridization (FISH) within their own karyotypes and in three additional Suliformes species (S. sula, S. dactylatra, and Fregata magnificens). Results: Five satDNAs were identified in S. leucogaster and eight in N. brasilianum. Within the genus Sula, three species shared specific satDNA sequences, although with different hybridization patterns. In contrast, the satDNAs of N. brasilianum were species-specific. Additionally, the Z chromosome, including Z₂ in Sula species, showed reduced accumulation of repetitive DNAs. Conclusions: These results suggest that differential accumulation of repetitive sequences may have contributed to the diversification of karyotypes in this group, particularly influencing the structure and differentiation of sex chromosomes. Full article