Cytogenetic and Genome Research最新文献

{"title":"Diagnostic Utility of Chromosomal Microarray Analysis in a Turkish Pediatric Cohort: Insights from 1,022 Patients with Neurodevelopmental Disorders and Congenital Anomalies.","authors":"Aslihan Sanri, Mehmet Burak Mutlu, Ozlem Sezer","doi":"10.1159/000549248","DOIUrl":"10.1159/000549248","url":null,"abstract":"<p><strong>Background: </strong>Chromosomal microarray analysis (CMA) is a first-tier diagnostic test for children with unexplained developmental and/or congenital anomalies. This study aimed to evaluate the diagnostic contribution of CMA in a large, phenotypically diverse Turkish pediatric cohort.</p><p><strong>Methods: </strong>CMA was performed in 1,022 children presenting with developmental delay, intellectual disability, autism spectrum disorder, epilepsy, and/or congenital anomalies. Copy number variants (CNVs) were classified as pathogenic, likely pathogenic, or variants of uncertain significance based on American College of Medical Genetics guidelines.</p><p><strong>Results: </strong>CNVs were identified in 279 patients (27.3%), totaling 315 CNVs. Of these, 151 patients (14.8%) carried at least one pathogenic or likely pathogenic CNV, representing the diagnostic yield of the study. CNVs were more frequently classified as pathogenic when presenting as deletions. The diagnostic rate was higher among patients with syndromic features (20.2%) compared to those with isolated developmental delay/intellectual disability (11.8%). Among patients with CNVs, 139 (49.8%) exhibited phenotypes consistent with well-characterized genomic syndromes. In addition, rare but clinically significant CNVs were also identified, involving well-established dosage-sensitive genes. Notably, chromosomes X, 15, and 16 were among the most frequently affected, reflecting known genomic hotspots associated with neurodevelopmental and structural phenotypes.</p><p><strong>Conclusion: </strong>CMA is a powerful diagnostic tool in the evaluation of pediatric patients with neurodevelopmental and structural disorders. This study emphasizes the added value of high-resolution CNV detection and careful clinical phenotyping to optimize diagnostic yield and guide precision care in clinically heterogeneous pediatric populations.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"1-34"},"PeriodicalIF":1.3,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145457782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High Amplification of CLA-SAT-149 Satellite DNA in Bighead Catfish: Insights into Satellite DNA Evolution in Clariid Lineages.","authors":"Worapong Singchat, Wattanawan Jaito, Trifan Budi, Thitipong Panthum, Narongrit Muangmai, Chaiwut Grudpan, Jarungjit Grudpan, Suphada Kiriratnikom, Kyudong Han, Darren K Griffin, Prateep Duengkae, Yoichi Matsuda, Kornsorn Srikulnath","doi":"10.1159/000548841","DOIUrl":"10.1159/000548841","url":null,"abstract":"<p><strong>Introduction: </strong>Satellite DNA (satDNA) is an important component of eukaryotic genomes that influences chromosomal organization and evolution. This study investigates the sequence diversity, chromosomal distribution, and copy number variation of the CLA-SAT-149 satDNA family (149 bp) in four clariid catfish species, Clarias macrocephalus, C. gariepinus, C. batrachus, and C. nieuhofii, as well as in F₁ hybrids and backcross (BC) progeny.</p><p><strong>Methods: </strong>Fluorescence in situ hybridization (FISH) was used to map CLA-SAT-149 on metaphase chromosomes. Quantitative PCR (qPCR) quantified copy number variation. Amplicon sequencing was applied to characterize sequence variants, and Bayesian clustering analysis was used to assess genetic relationships among subfamilies.</p><p><strong>Results: </strong>Chromosome mapping showed species-specific signals present in C. macrocephalus and F₁ hybrids but absent in C. gariepinus and C. nieuhofii. qPCR revealed significantly higher copy numbers in C. macrocephalus. Two sequence variants were identified: the canonical 149-bp (subfamily A) and an 85-bp derivative (subfamily B). Bayesian analysis indicated multiple genetically distinct subgroups among species. F₁ hybrids and BC progeny exhibited unique sequence profiles and copy number patterns, while C. nieuhofii lacked CLA-SAT-149 entirely.</p><p><strong>Conclusion: </strong>The results support lineage-specific expansion, amplification, and loss of CLA-SAT-149 in clariid catfish, consistent with the satDNA library model. These patterns provide insights into satDNA evolution and have potential applications in aquaculture genetics, hybrid identification, and species differentiation.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"1-17"},"PeriodicalIF":1.3,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145243450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular Mechanisms of Proliferative Senescence and Genomic Instability in Werner Syndrome and the WRN Gene Network.","authors":"Martin Poot","doi":"10.1159/000548500","DOIUrl":"10.1159/000548500","url":null,"abstract":"<p><strong>Background: </strong>Ageing is a general, intrinsic, and progressively deleterious process that affects all cells, tissues, and organs albeit at different extent and rate in each individual. The complexity and universality of its phenotypic manifestations suggest a multifactorial origin. The autosomal recessive disorder Werner syndrome likely represents a segmental progeroid disorder since patients show several, but not all phenotypes of premature ageing.</p><p><strong>Summary: </strong>Proliferative senescence of diploid cells in culture provided a model system in which ageing can be studied experimentally. Cultures of cells from patients with Werner syndrome experienced an extreme form of proliferative senescence and a clonal succession of translocations, known as variegated translocation mosaicism. In addition, Werner syndrome cells showed spontaneous deletion formation and a prolongation of and arrest in the S phase of the cell cycle. The WRN protein harbours a helicase, an exonuclease and a RecQ interaction domain. With the latter, the WRN protein may interact with NBS1, Replication Protein A (RPA), MRE11, TREX1, MUTYH, POT1, TRF1, FEN-1, PAPRP-1, p97/VCP, TRF2, DNA polymerase(beta), Ku76/80, EXO-1, NEIL1, and p53, which are key to DNA damage response pathways including canonical NHEJ, homologous recombination, base excision repair, and telomere maintenance. The WRN exonuclease domain is a target of WRNIP1 binding, which links WRN to resolution of stalled replication due to collision with transcription and the ATM-mediated cell cycle checkpoint. Patients with an incomplete complement of Werner syndrome phenotypes, called atypical Werner syndrome patients, were found to carry variants in LMNA, POLD1, SPRTN, MDM2, CTC1, SAMHD1.</p><p><strong>Key messages: </strong>These findings broaden the genotypic landscape and the phenotypic spectrum of Werner syndrome. In this review potential molecular mechanisms underlying genomic instability in Werner syndrome, including chromothripsis due to asynchronous S phase traverse and telomere crises followed by bridge fusion breakage cycles are discussed. The participation of WRN in multiple gene networks is consistent with the multifactorial nature of ageing in general.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"1-20"},"PeriodicalIF":1.3,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145091363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Post-Translational Modifications of the Werner Syndrome Protein WRN.","authors":"Amrita Machwe, David K Orren","doi":"10.1159/000547163","DOIUrl":"10.1159/000547163","url":null,"abstract":"<p><strong>Background: </strong>Werner syndrome has been an excellent model for the study of human aging and how chromosomal instability is related to phenotypes of normal aging including cancer. George Martin devoted his life to the study of Werner syndrome and human aging, and this review is dedicated to his memory.</p><p><strong>Summary: </strong>In this review, we highlight the post-translational modifications of WRN, the protein whose function is lacking in individuals with Werner syndrome. WRN is subject to phosphorylation, acetylation, ubiquitination, and SUMOylation.</p><p><strong>Key messages: </strong>These modifications of WRN control its localization and function in the response to replication fork stress and repair of double-strand breaks that are a consequence of this stress.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"1-7"},"PeriodicalIF":1.3,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144552594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic and Epigenetic Insights into Werner Syndrome.","authors":"Elena Paccosi, Diletta Guzzon, Luca Proietti-De-Santis","doi":"10.1159/000544118","DOIUrl":"10.1159/000544118","url":null,"abstract":"<p><strong>Background: </strong>Werner syndrome is an autosomal recessive disorder characterized by premature aging and cancer predisposition, caused by loss of function mutations in WRN gene. To date, more than 70 different pathogenic variants have been identified across the WRN locus, with an increasing number of newly reported mutations. Even if the clinical phenotypes of WS seem to be indistinguishable among the different WRN mutation types, a certain genotype/phenotype correlation has been identified, especially regarding the predisposition to certain type of malignant disease. Along this line, the knowledge of the genetic aspects related to WRN is a fascinating land still object of intensive studies. Summary and Key Messages: In this review, we discuss both the genetic and epigenetic regulations of the WRN gene, with a special focus on the pathogenic variants that have been identified in the WRN locus across different populations. Indeed, we think that investigating these aspects is the basis starting from which is it possible to depict WRN role in aging and cancer development processes, with the final goal of opening new perspectives for future therapeutic strategies directed to the treatment not only of this syndrome, for which, to date, there is no cure, but also of many types of malignant diseases and all those disturbs related to the physiological aging.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"1-15"},"PeriodicalIF":1.7,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143432322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In situ and in silico Localization of Major Satellite DNAs in the Genome of the Red-Eared Slider (<italic>Trachemys scripta elegans</italic>, Emydidae, Testudines).","authors":"Svetlana Romanenko, Svetlana A Romanenko, Dmitry Yu Prokopov, Sergey A Marchenko, Maria M Kulak, Arina V Ilina, Natalia A Serdyukova, Svetlana A Galkina, Vladimir A Trifonov","doi":"10.1159/000544908","DOIUrl":"10.1159/000544908","url":null,"abstract":"<p><strong>Introduction: </strong>Satellite DNA is an important component of the eukaryotic genome. Some satellite DNAs plays an important role in various biological processes. The red-eared slider (Trachemys scripta elegans, 2n = 50, C = 1.43 pg) belongs to the American freshwater turtle family and is recognized as one of the world's most invasive species. In the T. s. elegans chromosome-level genome assembly, which has been recently published, satellite DNAs comprise only 0.1%. From the repetitive repertoire of the T. elegans genome, only ribosomal DNA genes and telomeric repeats have been localized on the species' chromosomes.</p><p><strong>Methods: </strong>Using publicly available short-read sequencing data, we conducted de novo identification of the most abundant satellite DNAs in T. s. elegans using the TAREAN pipeline. We combined bioinformatics (using blastn) and chromosome mapping by fluorescence in situ hybridization to describe the distribution of major tandem repetitive DNAs. The diversity and distribution of satDNA in the assembled genome of T. s. elegans were explored using the SatXplor pipeline.</p><p><strong>Results: </strong>Six major satellite sequences occupying approximately 0.8% of the genome were identified in the genome data, all of which were successfully localized both in situ and in silico on T. s. elegans chromosomes and in silico on chromosomal scaffolds. We revealed a complex structural organization of these sequences: monomers may be moderately or highly variable and they may contain regions homologous to retrotransposons. Cytogenetic mapping showed the accumulation of satellite DNAs in the pericentromeric regions of most chromosomes and in the distal regions of the short arms of submetacentric chromosomes. Comparisons between cytogenetic maps and genome assembly data revealed discrepancies in the number and chromosomal locations of the identified satellite DNA clusters.</p><p><strong>Conclusion: </strong>The red-eared slider genome has a greater proportion of satellite DNA than was previously reported. These satellites demonstrate no specificity for either macrochromosomes or microchromosomes. Differences between in situ and in silico results indicate the challenges of repetitive sequence assembly, as well as discrepancies between chromosome numbering in the current chromosome-level genome assembly and the physical chromosome map.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"162-174"},"PeriodicalIF":1.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143604274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kallmann Syndrome due to Balanced X Chromosomal Pericentric Inversion Disrupting ANOS1.","authors":"Michihiko Aramaki, Takashi Hamajima, Erina Suzuki, Maki Fukami, Keiko Matsubara","doi":"10.1159/000545695","DOIUrl":"10.1159/000545695","url":null,"abstract":"<p><strong>Introduction: </strong>Kallmann syndrome (KS) is a rare congenital disorder characterized by hypogonadotropic hypogonadism and anosmia/hyposmia. KS primarily results from nucleotide substitutions and copy number variations in known causative genes. Only one balanced X chromosomal inversion involving ANOS1 has been identified in a patient.</p><p><strong>Case presentation: </strong>We encountered a boy with typical clinical features of KS. G-banding showed a 46,Y,inv(X)(pter→p22.32::q21.1→p22.32::q21.1→qter) karyotype, and whole genome sequencing and array-based comparative genomic hybridization detected a copy number neutral pericentric inversion involving a 72-Mb region. The breakpoints were mapped to ANOS1 intron 3 and an intergenic region at Xq21.1. The two breakpoints shared a 3-bp complementary sequence but were not associated with repetitive elements or nucleotide insertions at the fusion junction.</p><p><strong>Conclusion: </strong>These results indicate that KS-causative inversions on the X chromosome can arise from replication-based errors. Furthermore, our data provide evidence that balanced X chromosomal inversions constitute a rare monogenic cause of KS.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"93-98"},"PeriodicalIF":1.7,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143973424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Whole-Arm Chromosome Rearrangements and Telomeric Signal Displays: Current Cytogenetic Updates on Two Target Mammalian Taxa.","authors":"Svetlana Pavlova, Nina S Bulatova, Alexander S Graphodatsky, Victor Spangenberg, Svetlana V Pavlova","doi":"10.1159/000545600","DOIUrl":"10.1159/000545600","url":null,"abstract":"<p><strong>Introduction: </strong>Here we compare differences in the presence of telomeric signals (tDNA-FISH) among karyotypes of taxa having different whole-arm chromosomal rearrangements under the assumption of their participation in differentiation/integration processes during karyotype evolution. We analyzed the cytogenetic peculiarities of Robertsonian-like (centromeric) and tandem (telomere-involving) rearrangements using examples of the authors' recent research on comparative cytogenetics of mammals. New data on intra- and interspecific karyotype variation helped understand the nature of chromosomal rearrangements and their molecular features within and between species in two target mammalian taxa: representatives of two genera from two orders (insectivores and rodents).</p><p><strong>Methods: </strong>To detect telomeric repeats in karyotypes of representatives of the Eurasian genus Sorex and Ethiopian endemic Stenocephalemys, G-banded metaphase chromosomes were hybridized in situ with a fluorescein-conjugated peptide nucleic acid probe and 5'-TAMRA-labeled (CCCTAA)₄ oligonucleotides.</p><p><strong>Results: </strong>We compared the location of a molecular chromosomal trait - telomeric sequences - among karyotypes of taxonomically distinct individuals having different types of whole-arm chromosomal rearrangements. Along with the regular terminal location of the telomeric signal on all chromosomes, displays of interstitial telomeric sequences (ITSs) were detectable. This pattern was typical for a studied shrew specimen whose karyotype corresponded to a natural interracial F1 hybrid. This finding doubles the number (known to date) of S. araneus race-specific metacentrics having an identified telomeric signal. In karyotypes of Stenocephalemys specimens, we revealed individual differences in autosomes corresponding to tandem fusion rearrangements, possibly species-specific, for the first time. No intrachromosomal telomeric signal expected in this case was detectable in autosomes, whereas we registered ITSs in pericentromeric regions on X chromosomes near a short, completely heterochromatic (additional) arm.</p><p><strong>Conclusion: </strong>The new data indicate a heterogeneous distribution of the telomeric signal (tDNA-FISH) on mitotic chromosomes that are involved in (typical for mammals) whole-arm chromosomal variation, thus representing two models of karyotype evolution: Robertsonian polymorphism and tandem fusions. In the analyzed examples of whole-arm chromosomal rearrangements, displays of the centromeric ITS signal more likely represent an integral feature of cytogenetic relatedness within a species (chromosomal races) or between species (in a genus or group of genera) than differentiation of taxa.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"140-148"},"PeriodicalIF":1.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143751563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on DNA Damage Gene in Spermatogonial Stem Cells from Idiopathic Nonobstructive Azoospermia: A Bioinformatics Investigation Based on scRNA-seq Data.","authors":"Yi Wang, Yiming Weng, Yanqiu Wang, Jun Xiang, Wei Le","doi":"10.1159/000545275","DOIUrl":"10.1159/000545275","url":null,"abstract":"<p><strong>Introduction: </strong>DNA damage may affect homeostasis on spermatogonial stem cells (SSCs), while the detailed relationship with male infertility still remains unclear. Therefore, it is important for further research into the mechanisms related to DNA damage and genomic stability in SSCs.</p><p><strong>Methods: </strong>scRNA-seq datasets from idiopathic nonobstructive azoospermia (NOA) and normal testes were collected and testicular cells were further annotated via UMAP. Based on annotation of the sequencing data, WGCNA analysis on the differentially expressed genes was conducted; LASSO regression and the MNC calculation algorithm in Cytoscape were carried out to find genes associated with DNA damage repair.</p><p><strong>Results: </strong>It was found that SSCs were mainly concentrated in normal samples, and the differences in subcluster pathways reflected the heterogeneity of NOA. While the characteristics of the interaction between Leydig cells and other cells were clarified, the importance of the PTN signaling pathway in SSCs development was discovered, which participates in SSCs development through SDC2. Combining the marker genes of SSCs and DNA damage-related genes in single-cell analysis, a PPI network was constructed. Through LASSO regression and the MNC calculation algorithm in Cytoscape, ATRX, DOT1L, and RUVBL2 were finally identified as key diagnostic genes.</p><p><strong>Conclusion: </strong>Our results revealed predictable mechanisms of testicular micro-environment and DNA damage in the regulation of human SSCs and propose potential therapeutic targets for male infertility. Subsequently, further research to confirm the predicted potential mechanisms, pathways, and therapeutic targets should be conducted.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"9-22"},"PeriodicalIF":1.7,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143656365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Karyotype and Repetitive DNA Analysis in Turcichondrostoma fahirae (Cypriniformes, Leuciscidae): A Step toward the Use of Molecular Cytogenetics in Taxonomy of Freshwater Fishes in Türkiye.","authors":"Güldane Gözen Tavşan, Atilla Arslan, Büşra Özçay Ekşi, Zafer Alpaslan, Emine Arslan, Alexandr Sember","doi":"10.1159/000544909","DOIUrl":"10.1159/000544909","url":null,"abstract":"<p><strong>Introduction: </strong>Türkiye houses rich freshwater ichthyofauna with many endemic species. This diversity, however, poses taxonomic challenges and leads to ongoing re-evaluations of various fish genera and species. Here, we sought to analyze the karyotype and other chromosomal characteristics of the newly erected monotypic genus Turcichondrostoma to produce and validate cytogenetic markers potentially informative for future comparative studies.</p><p><strong>Methods: </strong>We examined an endemic species Turcichondrostoma fahirae (Tefenni nase) using conventional karyotyping and chromosome banding procedures (C-, fluorescent, and silver-nitrate banding/staining), as well as chromosomal mapping of 5S/18S ribosomal DNA (rDNA), U1/U2 small nuclear DNA (snDNA), and telomeric repeats.</p><p><strong>Results: </strong>A diploid chromosome number (2n) of T. fahirae was 50, consistent with conservative leuciscid pattern. The karyotype was composed of 12 metacentric, 22 submetacentric, 10 subtelocentric, and 6 acrocentric chromosomes. Low amount of constitutive heterochromatin was distributed almost exclusively across the pericentromeric regions of all chromosomes, with the most prominent C-bands being placed on a single chromosome pair carrying nucleolar organizer region (NOR). NORs (visualized consistently by silver-nitrate staining, chromomycin A3, and fluorescence in situ hybridization) exhibited marked size heteromorphism and were adjacent to a more centromere-proximal 5S rDNA site on the long arm. Additional 5S rDNA clusters occupied short arms of four acrocentric chromosomes, and another single subtelocentric pair carried a single co-localized U1/U2 snDNA site. No interstitial telomeric sequences were detected.</p><p><strong>Conclusion: </strong>We performed a pioneer molecular cytogenetic study in Turkish freshwater fish species and our data suggest that molecular cytogenetic markers will aid in future taxonomic comparisons. Our findings further corroborate conserved karyotype structure of leuciscid fishes in general.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"39-50"},"PeriodicalIF":1.7,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143771494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}