Marker Chromosomes Research Articles

Maternally Derived Complex Small Supernumerary Marker Chromosome 22 Associated with Cat-Eye Syndrome Like Features

Cat-eye syndrome (CES) is a rare genetic disease first reported in 1965. The estimated prevalence of CES is 1:50,000 to 1:150,000, and it is typically associated with an inverted duplicated small supernumerary marker chromosome (sSMC) derived from chromosome 22. The specific chromosomal band involved in CES causing partial tetrasomy is 22q11.21, where chromosomal rearrangements occur due to the presence of low-copy repeats (LCR22). The phenotype of CES is extremely diverse, ranging from normal to multiple abnormalities including intellectual disabilities and dysmorphic features. To our knowledge, over 340 patients with CES have been reported to date. This study reports a patient displaying a duplication of chromosome 22pter-22q12 involving band 22q11.21 where the CES critical region is located, and 18pter to 18p11. The propositus is a three-year-old girl, born to an unrelated and healthy couple. She was referred for facial dysmorphism and psychomotor delay. Banding cytogenetic analysis revealed an sSMC resulting from abnormal 3:1 segregation of the maternal balanced translocation t(18;22). Furthermore, the origin of the sSMC was confirmed by fluorescence in situ hybridization technique. The current study emphasized the importance of molecular cytogenetic techniques such as FISH in apprehending chromosomal abnormality. In addition, it shows that partial trisomy 22q11.2 to 22q12 may lead to CES-like symptoms.

The first insight into Acanthocephalus (Palaeacanthocephala) satellitome: species-specific satellites as potential cytogenetic markers

Acanthocephalan parasites are often overlooked in many areas of research, and satellitome and cytogenetic analyzes are no exception. The species of the genus Acanthocephalus are known for their very small chromosomes with ambiguous morphology, which makes karyotyping difficult. In this study, we performed the first satellitome analysis of three Acanthocephalus species to identify species- and chromosome-specific satellites that could serve as cytogenetic markers. RepeatExplorer2 revealed a remarkably high number of species-specific repeats, with a predominance of satellite DNAs, alongside variations in repetitive content between sexes. Five satellites in A. anguillae, two in A. lucii and six in A. ranae were successfully mapped to chromosomes using FISH. Each satellite showed a clustered hybridization signal at specific chromosomal locations, which allowed us to create a schematic representation of the distribution of satellites for each species. These newly identified satellites proved to be useful chromosomal markers for the accurate identification of homologous chromosome pairs. No FISH-positive signals were observed on the supernumerary chromosomes of A. anguillae and A. lucii, supporting the hypothesis that these chromosomes have recent origin.

SnoRNA box C/D levels in leukemia cells in chromosomal abnormalities after irradiation

The study objective. This paper reviews the express of C/D box snoRNAs (small nucleolar RNAs) and possibility of their use as biomarkers of radioresistance in chromosomal abnormalities. Material and Methods. The study compared the values of log2FC express of snoRNA C/Dbox in radiosensitive (HL-60) and radioresistant (K562) cell lines with different levels of chromosomal abnormalities. The cells were irradiated with X-ray radiation once at a dose of 4 Gy. The expression of snoRNA C/D was evaluated 1, 4 and 24 hours after irradiation, using new generation sequencing (NGS) MiSeq. Results. Different log2FC values were obtained in HL-60 and K562 cell lines 1 hour, 4 and 24 hours after irradiation. Positive expression of C/D snoRNA prevails in HL-60 throughout the experiment. In K562, the predominance of positive values of C/D snoRNA expression was observed 4 hours after irradiation, and negative values of log2FC were observed 24 hours later. the more anomalies there were in the chromosome, the greater the difference in expression we observed. at the same time, the number of C/D snoRNA changed maximally 24 hours after irradiation in the studied cell lines. We noted a greater number of C/D snoRNAs in the HL-60 cell line, and only 3 expressed C/D snoRNAs in the 15th marker chromosome in K562 out of 16 in HL-60 in the same chromosome. Conclusion. Our study showed a low informative value of using C/D snoRNAs family as markers of radiosensitivity in the presence of chromosomal abnormalities in cancer cells.

Genetic parameters and genome-wide association studies including the X chromosome for various reproduction and semen quality traits in Nellore cattle

BackgroundThe profitability of the beef industry is directly influenced by the fertility rate and reproductive performance of both males and females, which can be improved through selective breeding. When performing genomic analyses, genetic markers located on the X chromosome have been commonly ignored despite the X chromosome being one of the largest chromosomes in the cattle genome. Therefore, the primary objectives of this study were to: (1) estimate variance components and genetic parameters for eighteen male and five female fertility and reproductive traits in Nellore cattle including X chromosome markers in the analyses; and (2) perform genome-wide association studies and functional genomic analyses to better understand the genetic background of male and female fertility and reproductive performance traits in Nellore cattle.ResultsThe percentage of the total direct heritability (h2total) explained by the X chromosome markers (h2x) ranged from 3 to 32% (average: 16.4%) and from 9 to 67% (average: 25.61%) for female reproductive performance and male fertility traits, respectively. Among the traits related to breeding soundness evaluation, the overall bull and semen evaluation and semen quality traits accounted for the highest proportion of h2x relative to h2total with an average of 39.5% and 38.75%, respectively. The total number of significant genomic markers per trait ranged from 7 (seminal vesicle width) to 43 (total major defects). The number of significant markers located on the X chromosome ranged from zero to five. A total of 683, 252, 694, 382, 61, and 77 genes overlapped with the genomic regions identified for traits related to female reproductive performance, semen quality, semen morphology, semen defects, overall bulls’ fertility evaluation, and overall semen evaluation traits, respectively. The key candidate genes located on the X chromosome are PRR32, STK26, TMSB4X, TLR7, PRPS2, SMS, SMARCA1, UTP14A, and BCORL1. The main gene ontology terms identified are “Oocyte Meiosis”, “Progesterone Mediated Oocyte Maturation”, “Thermogenesis”, “Sperm Flagellum”, and “Innate Immune Response”.ConclusionsOur findings indicate the key role of genes located on the X chromosome on the phenotypic variability of male and female reproduction and fertility traits in Nellore cattle. Breeding programs aiming to improve these traits should consider adding the information from X chromosome markers in their genomic analyses.

Assessment of the pathogenicity of Y. enterocolitica B1A isolates from San Luis, Argentina.

Yersinia enterocolitica, a bacterial enteropathogen that produces a variety of clinical manifestations in humans, includes six biotypes (B), called 1A, 1B, 2, 3, 4 and 5 and about 70 serotypes. The biotypes exhibit diverse pathogenic potential; while 1B and 2-5 may show ability to produce clinical symptoms due to the presence of chromosomal and plasmid (pYV) virulence genes, B1A is supposed a non-pathogenic biotype since it lacks pYV plasmid. Therefore, although B1A strains cause diarrhea in humans, their pathogenic potential has not yet been extensively studied. The objective of this study was to assess virulence genetic markers of local Y. enterocolitica B1A strains and determine clonal relationships between isolates. To this, Y. enterocolitica chromosomal virulence markers were evaluated by PCR, Yst enterotoxin activity of culture filtrates in the intestine of suckling mice was tested and PFGE was applied in 24 Y. enterocolitica B1A strains obtained from human feces, foods, animals and environmental samples of our region (isolated among 2000-2014). The detection frequency of virulence chromosomal markers was as follows: fepA [95.8% (23/24)], ystB [91.7% (22/24)], hreP [87.5 % (21/24)], tccC [12.5% (3/24)] and myfA [4.2% (1/24)]. Presence of ystB gene was strongly associated to the Yst activity in suckling mice. By PFGE, B1A strains were divided into 10 genomic patterns (GP). Interestingly, human strains showed 88% similarity when compared to strains of the same serotype from other sources. Our results support the pathogenicity of Y. enterocolitica B1A strains and highlight the valuable impact of the Y. enterocolitica monitoring to prevent and control the spreading of this pathogen in our region.

Assessing the genomic diversity of a NW Spain bloom of Alexandrium minutum using satDNAs as chromosomal markers

Assessing the genomic diversity of a NW Spain bloom of Alexandrium minutum using satDNAs as chromosomal markers

A cost-effective oligo-based barcode system for chromosome identification in longan and lychee.

Oligonucleotide (Oligo)-based fluorescence in situ hybridization (FISH) represents a highly effective methodology for identifying plant chromosomes. Longan is a commercially significant fruit species, yet lacking basic chromosomal markers has hindered its cytogenetic research. In this study, we developed a cost-effective oligo-based system for distinguishing chromosomes of longan (Dimocarpus longan Lour., 2n = 2x = 30). For this system, each synthesized oligo contained two chromosome-specific sequences that spanned a distance of over 200kb, and a PCR-based flexible amplification method coupled with nested primers was used for probe labeling. The use of these oligo-based barcodes enabled the marking of 36 chromosomal regions, which allowed for the unambiguous distinction of all 15 chromosomes in both longan and lychee (Litchi chinensis Sonn., 2n = 2x = 30) species. Based on the identification of individual chromosomes, we constructed karyotypes and detected genome assembly errors involving the 35S ribosomal RNA gene (35S rDNA) in longan and lychee. Developing oligo-based barcodes offers considerable promise for advancing cytogenetic research in longan, lychee, and their related species. Furthermore, this cost-effective synthesis system can be referred to the development of new oligo libraries among other species.

Sub-toxic cisplatin concentrations induce extensive chromosomal, nuclear and nucleolar abnormalities associated with high malignancy before acquired resistance develops: Implications for clinical caution.

This study investigates the impact of sub-toxic cisplatin levels on nuclear and nucleolar abnormalities and chromosome instability in HeLa cells since our current knowledge of cisplatin effects on these parameters is based on studies with high concentrations of cisplatin. HeLa cells were exposed to gradually increasing sub-toxic doses of cisplatin (0.01 to 0.2 μg/ml). Cells treated with 0.1 and 0.2 μg/ml, termed HeLaC0.1 and HeLaC0.2, were not cisplatin-resistant, only exhibiting a slightly reduced viability, and were termed "cisplatin-sensitized cells." Giemsa and silver staining were used to detect nuclear and nucleolar abnormalities and chromosomal alterations. Notable abnormalities were observed in HeLaC0.1 and HeLaC0.2 cells after treatment with sub-toxic concentrations of cisplatin: nuclei showed abnormal shapes, blebs, micronuclei, fragmentation, pulverization, and multinucleation; nucleoli exhibited irregular shapes and increased numbers; anaphase cells showed more nucleolar organizing regions. Abnormal chromosome segregation, heightened aneuploidy (81-140 chromosomes), polyploidy, double minutes, dicentrics, chromatid exchanges, chromatid separations, pulverization, and chromosome markers were prominently noted. These abnormalities were intensified in cells pre-sensitized to 0.02 or 0.08 μg/ml cisplatin for seven days, then exposed to 0.03 or 0.1 μg/ml cisplatin for 24 hours, and finally cultured in cisplatin-free medium for 24 hours before chromosome analysis. HeLa cells subjected to increasing concentrations of sub-toxic cisplatin exhibited large-scale, multiple-type abnormalities in nuclei, nucleoli, chromosomes, and chromosomal numbers, indicating genetic/chromosomal instability associated with high malignancy, before the development of cisplatin resistance. These results suggest that low doses of cisplatin administration in the clinical setting may promote malignancy and caution should be used with this type of treatment.

РЕАЛИЗАЦИЯ В БОТАНИЧЕСКОМ САДУ САРАТОВСКОГО ГОСУНИВЕРСИТЕТА КОМПЛЕКСНОГО ПОДХОДА К ИЗУЧЕНИЮ И СОХРАНЕНИЮ БИОРАЗНООБРАЗИЯ РЕДКИХ ВИДОВ РАСТЕНИЙ

The preservation of floral diversity in the Saratov region is especially important. It occupies an extremely in- teresting botanical and geographical position, the consequence of which is that about half of the species are locat- ed on the border of their distribution and about 1/5 of them belong to the rare category. In the XX century, about 2% of the total number of species have already disappeared from the territory of the Saratov region. In this regard, the efforts of the scientific team of the Botanical Garden of the N.G. SSU. Chernyshevsky focuses on the imple- mentation of an integrated approach to studying the state of populations of rare and endangered species in the re- gion and developing effective measures to preserve and restore their numbers. The main objects of these studies in the last decade have been Tulipa suaveolens, Colchicum bulbocodium subsp. versicolor, Delphinium pubiflorum, Fritillaria, F. meleagroides, Globularia bisnagarica, Iris pumila and their closest relatives. In addition, populations of Calophaca wolgarica and Trapa natans, which disappeared from the flora of the region, were studied in adjacent territories for the purposes of reintroduction. The nature of morphological variability in the populations of these plant species was revealed by both traditional and geometric morphometry, the age, spatial and vital structure of populations, seed productivity, the structure of communities with the studied species, as well as the genetic struc- ture of populations using ISSR markers and markers of plastid and nuclear DNA. For some of the studied species, a comparative analysis of genomes was performed using chromosomal and molecular markers, as well as genome sizes. During the reintroduction of species to the Saratov region. From regions with different climatic conditions, the same algorithm was used to monitor polymorphism in prospective donor populations and identify genetic di- versity in natural populations in order to select the optimal genotypes of donor plants. After the creation of rein- troduction populations, they were compared with natural recipient populations in all these parameters. We con- ducted such studies in populations of Trapa natans L. Astrakhan, Volgograd and Voronezh regions and Calophaca wolgarica (L. fil.) DC. Volgograd and Rostov regions. In order to preserve biodiversity in the botanical garden of the SSU, an in vitro genetic bank of rare and endangered species of the Saratov region and adjacent territories has been created using the method of clonal micropropagation and deposition. Currently, 37 species of 27 genera of 17 families are supported in it under the conditions of deposit. Of these, 19 species, 15 genera and 12 families are listed in the Red Book of the Russian Federation.

Cytogenomic evaluation of regenerated Aralia elata using PLOP-FISH and flow cytometry

Aralia elata is closely related to Panax ginseng and contains high levels of saponins and other medicinal compounds. Successful A. elata micropropagation is commercially significant; however, the genomic stability of tissue culture-derived regenerants is unclear. In this study, callus-derived regenerated A. elata plants were obtained, and their cytogenomic constitutions were assessed. Using RepeatExplorer, pre-labeled oligonucleotide probes (PLOPs) were developed with newly mined tandem repeats from < 1× NGS whole-genome short reads, fluorescence in situ hybridization (FISH) was performed using six repeat probes, including three universal PLOPs, and genomic DNA content was estimated using flow cytometry. Regenerated A. elata plants (50) exhibited consistent ploidy, repeat distribution, and genome sizes compared with those exhibited by the mother plant. Six repeat probes were detected using FISH. Tandem repeat AeTR49 was identified as an excellent cytogenetic marker for homologous chromosomes, and AeTR161 and AeTR178 were localized in the centromeric and telomeric sections, respectively. Genomic DNA content (2C) was estimated at 2.46 ± 0.04 pg in the mother plant and 2.41 ± 0.05 pg in regenerated plants, with no significant variations in genome size or chromosome length. These results demonstrate that cytogenomics can be used to effectively evaluate chromosome-level genomic stability in regenerated A. elata plants.

МАРКЕРНЫЕ ХРОМОСОМЫ В КОНСТИТУЦИОНАЛЬНОМ КАРИОТИПЕ: ПРОБЛЕМЫ ДИАГНОСТИКИ

The article discusses the problems of identifying, diagnosing, and assessing the clinical significance of marker chromosomes in the constitutional karyotype. Priority approaches in cytogenetic diagnostics are discussed, based on modern ideas about the mechanisms of formation, structure and main types of marker chromosomes, as well as the need for an integrated approach in diagnostics. Our own data on the effectiveness of standard karyotyping and molecular cytogenetic studies are presented.

Repeatome Analysis and Satellite DNA Chromosome Patterns in Hedysarum Species.

The cosmopolitan genus Hedysarum L. (Fabaceae) is divided into sections Hedysarum, Stracheya, and Multicaulia. This genus includes many valuable medicinal, melliferous, and forage species. The species taxonomy and genome relationships within the sections are still unclear. We examined intra- and interspecific diversity in the section (sect.) Hedysarum based on repeatome analyses using NGS data, bioinformatic technologies, and chromosome FISH mapping of 35S rDNA, 5S rDNA, and the identified satellite DNA families (satDNAs). A comparison of repeatomes of H. alpinum, H. theinum, and H. flavescens revealed differences in their composition. However, similarity in sequences of most satDNAs indicated a close relationship between genomes within sect. Hedysarum. New effective satDNA chromosomal markers were detected, which is important for karyotype analyses within Hedysarum. Intra- and interspecific variability in the chromosomal distribution patterns of the studied markers were revealed, and species karyograms were constructed. These results provided new insight into the karyotype structures and genomic diversity within sect. Hedysarum, clarified the systematic position of H. sachalinense and H. arcticum, and confirmed the distant genomic relationships between species from sections Hedysarum and Multicaulia. Our findings are important for further comparative genome studies within the genus Hedysarum.

Genetic and cytogenetic analysis of Moringa oleifera short and long capsule phenotypes

Cytogenetic and molecular studies hold significant importance in plant breeding programs. In the case of moringa, such studies are scarce. Therefore, the objective of this research was to determine the chromosomal number and genetic diversity parameters in two phenotypes of Moringa oleifera Lam. (short and long capsule) using chromosomal analysis and ISSR markers, respectively. Cytogenetic analyses were conducted using the “Somatic chromosomes in root apices” technique, with acetocarmine and papain for staining. It was possible to identify 2N = 28 chromosomes in a single cell of the long capsule phenotype, ranging in size from 0.05 to 0.10 μm. Cells in both moringa phenotypes were observed in prophase, metaphase, anaphase, and telophase. High genetic variability was found in both phenotypes of moringa, as indicated by a Shannon index of 0.81. Additionally, the principal component analysis and UPGMA (Unweighted Pair-Group Method with Arithmetic) groups revealed genetic isolation between the studied moringa phenotypes. The significant polymorphism obtained with most primers suggests that the tested ISSR markers are highly useful for studying genetic diversity in moringa. These findings provide a robust foundation for future research in genetic improvement and conservation of moringa, highlighting the relevance of cytogenetic and molecular studies in this species.

Prenatal diagnosis analysis of three cases of Turner syndrome fetuses with complex mosaic small supernumerary marker chromosomes

To explore the value of applying multiple genetic testing techniques for the prenatal diagnosis of Turner syndrome fetuses with complex mosaic small supernumerary marker chromosomes (sSMC). Chromosomal karyotypes of amniotic fluid samples from 5 030 pregnant women who had undergone amniocentesis at the Prenatal Diagnosis Center of the Third Affiliated Hospital of Zhengzhou University from January to December 2022 were retrospectively reviewed. Three fetuses with complex mosaicism fetuses (carrying 2 types of sSMC) were selected as the study subjects. Genetic tests including G-banded chromosomal karyotyping analysis, fluorescence in situ hybridization (FISH), chromosomal microarray analysis (CMA), and copy number variation sequencing (CNV-seq) were used to clarify the origin and mosaic status of the sSMC. This study has been approved by the Medical Ethics Committee of the Third Affiliated Hospital of Zhengzhou University (No. 2023-159-01). G-banded chromosomal analysis of fetus 1 showed a karyotype of 45,X[64]/46,X,+mar1[13]/46,X,+mar2[3]. FISH results showed that 52% of of its cells had contained one X chromosome signal, whilst 48% contained two X chromosome signals. CMA results revealed the fetus had harbored a 32.32 Mb and a 50.93 Mb deletion in Xp22.33p21.1 and Xq22.2q28 regions, respectively, in addition with mosaic deletions of approximately 1.43 copies, 1.78 copies and 1.43 copies in the Xp21.1p11.1, Xq11.1q21.1 and Xq21.2q22.2 regions, respectively. The fetus 2 had a karyotype of 45,X[27]/46,X,+mar1[14]/46,X,+mar2[12]. FISH results indicated that 88% of its cells contained one X chromosomes signal and two Y chromosome signals, and 12% contained signals for one X chromosomes signal and one Y chromosome signal. CNV-seq results revealed a deletion of 7.74 Mb in the Yq11.222q11.23 region and a mosaic duplication of approximately 1.738 copies in the Yp11.31q11.221 region. The fetus 3 had a karyotype of 45,X[60]/46,X,+mar1[11]/46,X,+mar2[6]. FISH results showed that 28% of its cells contained one X chromosome signal, and 72% contained tow X chromosome signals. CNV-seq results revealed deletions of 55.60 Mb and 53.50 Mb in the Xp22.33p11.1 and Xq22.1q28 regions, respectively, along with a mosaic deletion of approximately 1.85 copies in the Xp11.1q13.2 region and a mosaic repeats of approximately 2.66 copies in the Xq13.2q22.1 region. The sSMCs in the 3 fetuses had all originated from sex chromosomes and were of complex mosaic type. After genetic counseling, the three couples had all opted to terminate the pregnancy. The combined use of multiple genetic testing techniques has determined the origin and structure of complex mosaic sSMCs and provided a basis for prenantal diagnosis and genetic counseling.

Real-time plasmid transmission detection pipeline.

Plasmid-mediated spread of antimicrobial resistance is a major challenge for clinical microbiology, and monitoring of potential plasmid transmissions is essential to combat further dissemination. Whole-genome sequencing is often used to surveil nosocomial transmissions but usually limited to the detection of clonal transmissions (based on chromosomal markers). Recent advances in long-read sequencing technologies enable full reconstruction of plasmids and the detection of very similar plasmids, but so far, easy-to-use bioinformatic tools for this purpose have been missing. Here, we present an evaluation of an innovative real-time plasmid transmission detection pipeline. It is integrated into the GUI-based SeqSphere+ software, which already offers core-genome multi-locus sequence typing-based pathogen outbreak detection. It requires very limited bioinformatics knowledge, and its database, automated analyses, and alert system make it well suited for prospective clinical application.

A haplogroup-based methodology for assigning individuals to geographical regions using Y-STR data

Y chromosome markers are essential tools in forensic genetics, offering valuable insights for genetic identification. This study seeks to develop a forensic prediction model using machine learning techniques to improve the efficiency of genetic identification processes. Specifically, the model aims to predict an individual's nearest geographical area of residence based on Y chromosome marker analysis. The methodology involved four key steps: haplogroup determination, primary branch identification, geographical region assignment, model stratification, and fine-tuning. Once developed, the model can be integrated into decision support systems, providing forensic geneticists with a reliable knowledge source to enhance decision-making during investigations.

Clinical and molecular cytogenetic findings of cat eye syndrome and a 2-year-old patient with congenital aural atresia and hearing loss

BackgroundCat eye syndrome (CES) is a rare congenital disease frequently caused by a partial tetrasomy of the proximal long (q) arm of chromosome 22, due to a small supernumerary marker chromosome (sSMC). CES patients show remarkable phenotypic variability. Despite the progress of molecular cytogenetic technology, the cause of phenotypic variability and the genotype–phenotype correlations remain unknown.MethodsWe analyzed clinical and genetic data of a new patient with CES together with 27 previously reported ones with a confirmed genomic gain in the PubMed database between 2012 and 2023.ResultsWe reported a boy with CES carrying a 22q11.1-q11.21 duplication of 1.76 Mb tetrasomy (16888900_18644241, hg19) who presented currently rare or unreported clinical findings such as congenital aural atresia, hearing loss, PLSVC, and IVC. The results of the whole exome sequencing (WES) showed a heterozygous mutation of the GJB2 gene (NM_004004.6: exon2: c.109G > A). In addition, the results of our literature review showed that the presence of a classical sSMC was the most frequent cytogenetic abnormality in CES (82%). 63% of cases were in a homogenous state and 37% of cases were in a mosaic state. 72% of cases had a 1–2 Mb duplication. In the majority of CES patients the breakpoints in chromosome 22 are localized to a 50 kb region (18610000_18660000 bp). The CES critical region (CESCR) may be further delimited to a 0.3 Mb region (17799398_18111588 bp). Within this region CECR2, SLC25A18, ATP6V1E1, and BCL2L13 are strong candidate genes for causing the main CES phenotype. The ear anomalies are the most frequent features in CES patients (89%) and hearing loss was present in 36% of CES patients.ConclusionsThe phenotypic features in CES are highly variable. Our findings expand the symptom spectrum of CES and lay the foundation for better delineating the clinical phenotype, molecular cytogenetic features associated with CES and genotype–phenotype correlations. We recommend performing WES to rule out the involvement of other genetic factors in the patient’s phenotype. In addition, our findings also highlight the need for genetic counseling and recurrence risk assessment.

Karyotype's Rearrangement in Some Hybrids of the Orchidinae Subtribe.

Based on our karyological findings in the Anacamptis Rich., Ophrys L., and Serapias L. genera, we have identified chromosomal markers within some hybrids and elucidated their interrelationships. Mitotic chromosomes of fifteen taxa were analyzed using the conventional Feulgen staining method. Only for Anacamptis ×gennarii (Rchb. f.) H.Kretzschmar, Eccarius & Dietr. [A. morio (L.) R.M.Bateman, Pridgeon & M.W.Chase × A. papilionacea (L.) R.M.Bateman, Pridgeon & M.W.Chase] and its parental species were some data obtained and reported with the banding method with Giemsa, Hoechst 33258 fluorochrome, and the FISH techniques. Our research involved new chromosomal measurements of fifteen taxa, including six hybrids, along with schematic representations. Morphometric parameters, i.e., MCA and CVCL, were used to evaluate karyotype asymmetry. Of meaning were the analyses performed on chromosomal complements of selected hybrids, which distinctly revealed marker chromosomes present in one or both putative parental species. Among the parents identified in some hybrids, Ophrys tenthredinifera Willd. has shown some interest due to the presence in its karyotype of a pair of chromosomes (n.1) showing a notable secondary constriction on the long arm. Indeed, one of the homologs is clearly distinguishable in the analyzed hybrids, where it clearly emerges as one of the putative parents. Given the challenges in detecting certain karyomorphological features within the Orchidinae subtribe using alternative methods, such as Giemsa C-banding or fluorescence banding, the Feulgen method remains valuable for cytogenetic characterization. It helps us to understand the genomes of hybrids and parental species, thus contributing to a deeper understanding of their genetic composition.

Prenatal diagnosis of a fetus with 15q11q13 complex duplication syndrome and a literature review

To explore the clinical features and genetic etiology of a fetus with 15q11q13 complex duplication syndrome. A fetus diagnosed with 15q11q13 duplication syndrome at Ningbo Women and Children's Hospital on April 19, 2023 was selected as the study subject. Clinical data was collected, and the fetus was subjected to invasive prenatal diagnosis including G-banded karyotyping and chromosomal microarray analysis (CMA). Following the discovery of chromosomal duplication, trio-whole exome sequencing was carried out to exclude single base variants and confirm the parental original of the duplication. Optical genome mapping was also performed to delineate the structural arrangement of the duplication. Relevant literature was searched in the PubMed, Wanfang Medical Network and CNKI databases using "15q11q13", "duplication", "hexasomy" and "Six fold repetition" as the key words from January 1, 2000 to August 1, 2023 for a review of previously reported 15q11q13 hexasomy cases. This study was approved by the Ningbo Women & Children's Hospital (Ethics No. EC2020-048). The fetus was found to have a mosaicism karyotype of 48,X?,+mar,+idic(15)(q13)[33]/47,X?,+idic(15)(q13)[17]. CMA and trio-WES have all shown a six-fold duplication in the PWS/AS critical region (PWACR) at 15q11.2q13.2 and quadruple duplication of 15q13.2q13.3 region, which have derived from its mother and formed supernumerary marker chromosomes (SMCs). Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the 15q11.2q13.2 sixfold duplication was classified as pathogenic, whilst the 15q13.2q13.3 quadruple duplication was classified as variant of uncertain significance. Literature search has identified 11 cases of 15q11q13 duplication involving hexasomy of the PWACR, with all cases showing mental retardation, language delay and hypotonia, and most of them also had motor retardation, epilepsy and mild facial dysmorphism. Hexasomy for the PWACR combined with tetrasomy of 15q13.2q13.3 probably underlay the left hand polydactyly, polyhydramnios and intrauterine growth retardation in this fetus.

Integrative morphological, cytogenetic and molecular characterization of the Andean climbing catfish Astroblepus mindoensis (Regan, 1916) (Siluriformes:Astroblepidae).

Astroblepus species, commonly known as Andean climbing catfish, exhibit a unique challenge in species delimitation, leading to ongoing taxonomic debates. Here we report data on Astroblepus mindoensis, a vulnerable species endemic to Ecuador, obtained by an integrative approach that includes cytogenetic analysis, molecular identification of the specimens, and recording of morphological and morphometric characters useful for species diagnosis. Thus, this study aimed to associate the karyotype data of the specimens analyzed with morphological and molecular characters, improving and expanding the existing taxonomic information, thus contributing to the systematics of the species. Our morphology results, unlike Regan's original description, which is brief and ambiguous, provide a more detailed morphometric and meristic description. Molecular phylogenetic reconstruction and genetic distance based on a fragment of the cytochrome c oxidase subunit I (COI) showed that our samples constitute a well-supported and monophyletic clade within the A. grixalvii species complex. The cytogenetic analysis identified distinct chromosomal markers, including a single cluster of major ribosomal genes (on chromosome pair 3) and of minor ribosomal genes (on chromosome pair 12) with their localization differing from those reported in other Astroblepus species analyzed. Additionally, the presence of a heteromorphic chromosome pair in males suggests the presence of an XX/XY sex-determination system that has not been identified in other congeneric species. Further investigation is necessary to determine if these chromosomes are associated with the accumulation of repeated sequences, as typically occurs with sex chromosomes, and to assess their presence in other species of the genus.