Chromosome Breakage Research Articles

Succinate dehydrogenase-B fluorescence in situ hybridization in pheochromocytoma-paragangliomas

Objective: Preoperative identification of familial pheochromocytoma and paraganglioma (PPGL) is crucial, yet often overlooked, leading to missed diagnoses. Typically, succinate dehydrogenase-B (SDHB) and fumarate hydratase (FH) tests are applied postoperatively to confirm familial links and assess prognosis. However, routine preoperative multidisciplinary collaboration is limited, causing delayed screening requests. Consequently, routine SDHB and FH immunohistochemistry (IHC) testing is not widely practiced. This study introduces SDHB fluorescence in situ hybridization (FISH) as a diagnostic tool, akin to HER2 IHC-FISH testing in gastric carcinomas. Materials and Methods: Succinate dehydrogenase-B and FH IHC were conducted on 43 cases. FISH analysis was performed for 28 cases with suspected familial origin or SDHB IHC loss to determine whether the protein loss was due to chromosomal changes. Results: Complete SDHB IHC loss occurred in 8 cases, partial loss in 4, and preservation in 31. Complete FH loss occurred in 10 cases. FISH analysis revealed chromosomal breaks in 20 cases (71.4%), including those with SDHB/FH IHC loss or positive clinical history. Ten cases (35.7%) showed a “red-signal only” pattern, suggesting further genetic testing. Conclusion: Succinate dehydrogenase-B FISH serves as a cost-effective tool for early PPGL diagnosis, complementing SDHB and FH IHC results. It can help identify cases that need genetic testing, even when IHC results are preserved.

Carbohydrate and mineral metabolism in romanov sheep in Western Siberia

The article presents information regarding the metabolism of carbohydrates and minerals in Romanov sheep in the Kemerovo region. The correlations among macro elements and carbohydrate metabolism indices and heavy metal levels in organs and tissues were ascertained. We determined the average content, variability and reference intervals of glucose, amylase, lactate dehydrogenase and macro elements in blood serum. We investigated the relationship between these indices and heavy metal levels in sheep organs and tissues. In the Romanov sheep breeding zone, heavy metal content was analyzed in soil, water, and feed and did not exceed the MAC. The determination of the content of macroand microelements was carried out in the laboratory of isotopegeochemical methods of analysis at the V.S. Sobolev Institute of Geology and Mineralogy of the Siberian Branch of the Russian Academy of Sciences by atomic emission spectrometry employing the NSAM analysis technique No. 450-S. The level of blood serum glucose is 6.0 mmol/l, the amylase is 104.0 U/l, and the lactate dehydrogenase is 1086 U/l. The order of macro elements in serum is as follows: Na > K > Ca > P > Mg in accordance with 90 : 7 : 4 : 3.4 : 1. The concentration of K in the blood exhibits a significant correlation with Zn in the spleen (r = 0.507) and Cu in the testes (r = 0.535). Simultaneously, Na exhibited a negative correlation with the concentration of Zn in the heart (r = -0.416) and Pb in the blood (r = −0.598). There was a high negative relationship between Ca in the blood and the frequency of chromosomal breaks (r = −0.752). The glucose level was negatively correlated with the concentration of Cu in the muscles (r = −0.414), Zn in the kidneys (r = −0.465), and Zn in the heart (r = −0.572), but its level was positively associated with Pb in the muscles (r = 0.568). The significance of the indicators of carbohydrate and mineral metabolism, as well as the correlations between the studied parameters, is evident in the comprehensive evaluation of the breeds phenopool.

Pediatric Transplant and Cellular Therapy Consortium RESILIENT Conference on Pediatric Chronic Graft-versus-Host Disease Survivorship after Hematopoietic Cell Transplantation: Part II. Organ Dysfunction and Immune Reconstitution Considerations for children with chronic GVHD after Hematopoietic Cell Transplantation.

While highly morbid forms of chronic graft versus host disease (cGVHD) and severe late effects of allogeneic hematopoietic cell transplant (HCT) can impact children and adults alike, unique considerations arise in pediatric cases regarding diagnosis, monitoring, treatment, and likelihood of resolution. As children can present with atypical features of cGVHD, and with more significant disease due to inability to communicate symptoms, they may be at increased risk for highly morbid forms of cGVHD and incur greater subsequent late effects, which may be more pronounced in those with underlying chromosomal breakage syndromes, with higher prevalence in pediatric HCT recipients. The long-term effects of cGVHD and its therapies include impaired immune reconstitution, leading to increased risks of infection and secondary malignant neoplasms. However, children also have the greatest potential for full immune reconstitution, due to thymus recovery that could impact the timing of vaccination with respect to tolerance and restoration of optimal immunity. Developing strategies to mitigate the late effects incurred with, and as a result of cGVHD, is of critical importance. The working group recommends surveillance strategies for late effects in patients with cGVHD, increased utilization of emerging diagnostic tools, integration of monitoring for cGVHD treatment response, development of new treatments, and provides aims for future research endeavors.

Sentinel role of military dogs in detecting genotoxic agents in the environment during military operations: a pilot study

During out-of-area military operations, the presence of carcinogenic and/or genotoxic agents has been reported, posing potential health risks to deployed soldiers. Military working dogs (MWDs), trained to detect explosives in the same environments as soldiers, could also serve as sentinel animals, providing valuable information on exposure to hazardous agents. These dogs can help identify environmental and potential adverse effects on their health and that of their handlers, possibly before relevant pathologies manifest. This study aims to evaluate the effectiveness of thirty-three Italian Army MWDs, deployed to the Lebanese theater for six consecutive months from October 2013 to January 2015, as sentinel animals for detecting exposure to genotoxic agents. The Cytokinesis-Block MicroNucleus (CBMN) assay was used to assess DNA damage, cytostasis, and cytotoxicity in the lymphocytes of these dogs. DNA damage events were specifically scored in once-divided binucleated cells (BCs) and included: a) micronuclei (MNi), indicative of chromosome breakage and/or whole chromosome loss; b) nucleoplasmic bridges (NPBs), a marker of DNA misrepair and/or telomere end-fusions; and c) nuclear buds (NBUDs), which signal the elimination of amplified DNA and/or DNA repair complexes. Our findings revealed an increase in chromosomal damage, assessed before and after deployment, with a statistically significant rise in MNi frequency, thus supporting the use of MWDs as sentinels for human exposure to hazardous agents.

Unveiling a pathogenic FANCA gene variant in a Mexican family with Fanconi anemia through next‑generation sequencing.

Fanconi anemia (FA) is the most common hereditary bone marrow failure syndrome, with an incidence of 1 in 5,000,000. This disease is caused by an alteration in one of the 23 genes associated with the FA/BRCA DNA repair pathway, which is responsible for repairing interstrand bridges generated during homologous recombination. FA has been associated with a predisposition to other types of neoplasm. The current study aimed to present a pathogenic variant in FANCA observed in three Mexican siblings, as detected by next-generation sequencing (NGS). The results of an induced chromosomal breakage test showed chromosomal breaks and radial figures, which were compatible with FA, and a normal karyotype. NGS TruSight Hereditary Cancer Panel analysis resulted in the FANCA:c.3931_3932delAG variant being classified as pathogenic according to bioinformatics analysis. The present study reports a pathogenic variant in FANCA that was found in a Mexican family with FA, in which one of the siblings exhibited a suggestive mucosa-assisted lymphoid tissue lymphoma, which is an atypical presentation of neoplasia associated with FA.

Assessment of the potential toxic of naringenin nanoparticles using ex vivo and in silico models.

Naringenin is a flavonoid known for its anti-inflammatory, antineoplastic, antiatherogenic, and antioxidant properties. However, it has poor technological characteristics and limited bioavailability, which hinder its use in food applications. Nanoencapsulation could address these limitations, but safety concerns regarding nanoengineered bioactives need to be resolved before they can be effectively utilized as food additives. The objective of this study was to evaluate the potential cytotoxic, genotoxic, and mutagenic effects of both free and encapsulated naringenin through in vivo experiments using Allium cepa L. roots, along with pharmacokinetic and molecular docking analyses. The results showed that naringenin nanoparticles did not produce significant changes in the cell division index of meristematic cells in A. cepa roots. Additionally, no significant alterations in the mitotic spindle or chromosomal breaks were observed. Molecular docking studies indicated that naringenin effectively binds to the active site of the catalase enzyme (CAT) in a competitive manner, while it attaches to a site away from the active site of superoxide dismutase (SOD2), demonstrating a non-competitive interaction. ADMET property assessments suggested that naringenin exhibits relatively low toxicity and has favorable molecular characteristics for oral administration. In summary, this study supports the potential of naringenin, particularly in its nanoencapsulated form, as a safe and effective ingredient for functional foods, provided that safety concerns regarding nanoencapsulation are adequately addressed.

DNA polymerase zeta can efficiently replicate structures formed by AT/TA repeat sequences and prevent their deletion.

Long AT repeat tracts form non-B DNA structures that stall DNA replication and cause chromosomal breakage. AT repeats are abundant in human common fragile sites (CFSs), genomic regions that undergo breakage under replication stress. Using an in vivo yeast model system containing AT-rich repetitive elements from human CFS FRA16D, we find that DNA polymerase zeta (Pol ζ) is required to prevent breakage and subsequent deletions at hairpin and cruciform forming (AT/TA)n sequences, with little to no role at an (A/T)28 repeat or a control non-structure forming sequence. DNA polymerase eta is not protective for deletions at AT-rich structures, while DNA polymerase delta is protective, but not in a repeat-specific manner. Using purified replicative holoenzymes in vitro, we show that hairpin structures are most inhibitory to yeast DNA polymerase epsilon, whereas yeast and human Pol ζ efficiently synthesize these regions in a stepwise manner. A requirement for the Rev1 protein and the modifiable lysine 164 ofproliferating cell nuclear antigen to prevent deletions at AT/TA repeats suggests a mechanism for Pol ζ recruitment. Our results reveal a novel role for Pol ζ in replicating through AT-rich hairpins and suggest a role for Pol ζ in rescue of stalled replication forks caused by DNA structures.

Megaloblastic anemia and chromosome breakages caused by low-quality diet in adolescent

Megaloblastic anemia and chromosome breakages caused by low-quality diet in adolescent

Proximity Proteomics Reveals USP44 Forms a Complex with BRCA2 in Neuroblastoma Cells and Is Required to Prevent Chromosome Breakage.

The enzyme ubiquitin-specific protease 44 (USP44) is a deubiquitinating enzyme with identified physiological roles as a tumor suppressor and an oncogene. While some binding partners and substrates are known for USP44, the identification of other interactions may improve our understanding of its role in cancer. We therefore performed a proximity biotinylation study that identified products of several known cancer genes that are associated with USP44, including a novel interaction between BRCA2 and USP44. We expressed a fusion protein that linked USP44 and mutant Escherichia coli biotin ligase BioID in SH-SY5Y neuroblastoma cells. Control experiments were performed using BioID alone. In duplicate experiments, cells were pulsed with biotin and biotinylated proteins were isolated under denaturing conditions and the proteins were identified by mass spectrometry. The resulting list of proteins were analyzed using Enrichr and cross-referenced with the COSMIC Cancer Gene Census. We validated the association with BRCA2 using immunoprecipitation. The role of USP44 in the Fanconi anemia DNA repair pathway was investigated using chromosome analysis of wild-type or Usp44-knockout cells after exposure to mitomycin C. We identified 146 proteins that were selectively retrieved by the USP44 construct and compared with cells expressing the BioID ligase alone, including 15 gene products encoded by genes on tier 1 of the COSMIC Cancer Gene Census, including BRCA2. The association between USP44 and BRCA2 was validated through immunoprecipitation. We tested the functional role of USP44 in the Fanconi anemia DNA repair pathway through chromosome breakage analysis and found that cells lacking USP44 had a significant increase in chromosome breaks and radial chromosomes. We found that high BRCA2 transcript was correlated with poor survival in neuroblastoma, likely due to its tight association with proliferation in these tumors. Our results identified novel potential binding partners and potential substrates for USP44, including several with direct roles in cancer pathogenesis. Our results identified a novel association between BRCA2 and USP44, and a previously unknown role for USP44 in the Fanconi anemia DNA repair pathway that may contribute to its role in cancer.

Precision genome editing using combinatorial viral vector delivery of CRISPR-Cas9 nucleases and donor DNA constructs.

Genome editing based on programmable nucleases and donor DNA constructs permits introducing specific base-pair changes and complete transgenes or live-cell reporter tags at predefined chromosomal positions. A crucial requirement for such versatile genome editing approaches is, however, the need to co-deliver in an effective, coordinated and non-cytotoxic manner all the required components into target cells. Here, adenoviral (AdV) and adeno-associated viral (AAV) vectors are investigated as delivery agents for, respectively, engineered CRISPR-Cas9 nucleases and donor DNA constructs prone to homologous recombination (HR) or homology-mediated end joining (HMEJ) processes. Specifically, canonical single-stranded and self-complementary double-stranded AAVs served as sources of ectopic HR and HMEJ substrates, whilst second- and third-generation AdVs provided for matched CRISPR-Cas9 nucleases. We report that combining single-stranded AAV delivery of HR donors with third-generation AdV transfer of CRISPR-Cas9 nucleases results in selection-free and precise whole transgene insertion in large fractions of target-cell populations (i.e. up to 93%) and disclose that programmable nuclease-induced chromosomal breaks promote AAV transduction. Finally, besides investigating relationships between distinct AAV structures and genome-editing performance endpoints, we further report that high-fidelity CRISPR-Cas9 nucleases are critical for mitigating off-target chromosomal insertion of defective AAV genomes known to be packaged in vector particles.

IRF-1 Regulates Mitochondrial Respiration and Intrinsic Apoptosis Under Metabolic Stress through ATP Synthase Ancillary Factor TMEM70.

Mitochondrial dysfunction, which can be caused by metabolic stressors such as oxidized low-density lipoprotein (oxLDL), sensitizes the endothelium to pathological changes. The transcription factor interferonregulatoryfactor 1 (IRF-1) is a master regulator of inflammation, previously shown to promote oxLDL-induced inflammatory pyroptosis in human aortic endothelial cells (HAEC). However, a presumed role for IRF-1 in regulating the intrinsic apoptotic pathway in response to metabolic stress has not been demonstrated. Here targeted deletion of IRF-1 by siRNA in HAEC aggravated oxLDL-induced, mitochondria-mediatedintrinsicapoptosis, as evidenced by increased Caspase-3 and Caspase-9 activation, and chromosomal DNA breakage. The increased apoptosis was concomitant with accumulation of mitochondrial ROS, decrease in intracellular ATP production and respiratory oxygen consumption, and abnormal mitochondrial structure. RNA profiling of endothelial cells isolated from wild type and Irf1 knockout mice, followed by quantitative PCR, luciferase activity assay and chromatin immunoprecipitation (ChIP), revealed that IRF-1 directly regulated the expression of transmembrane protein 70 (TMEM70), an ancillary factor required for the assembly of ATP synthase and conversion of an electrochemical gradient to ATP synthesis. Mirroring the effect of IRF1 knockdown, depletion of TMEM70 in HAEC resulted in impaired mitochondrial function and enhanced cell apoptosis. In contrast, overexpression of TMEM70 rescued ATP biosynthesis and suppressed apoptosis in oxLDL-treated, IRF-1-deficient HAEC. These results reveal a novel homeostatic role for IRF-1 in the regulation of mitochondrial function and associated stress-induced apoptosis.

Hepatitis-associated aplastic anaemia linked to increased chromosomal breaks: a case report

Hepatitis-associated aplastic anaemia linked to increased chromosomal breaks: a case report

Genetic structure of the population of Przewalski’s horse (Equus przewalskii) according to cytogenetic and ISSR markers

Background. Przewalski’s horse is included in the Red List of the International Union for Conservation of Nature and the Red Data Book of Ukraine as an endangered species. To confirm the uniqueness and consolidation of rare animal species, cytogenetic and molecular genetic monitoring is necessary. Obtaining biological material (blood) for genetic research is preceded by immobilization of wild ungulates. The successful selection of drugs for the purpose of sedation and analgesia helps to preserve the life and health of the animal. Materials and Methods. Przewalski’s wild horse population (10 heads) of the F. E. Falz-Fein “Askania-Nova” biosphere reserve, immobilization of animals with the Madison drug and the Reverson antidote, cytogenetic and molecular genetic (ISSR-fingerprinting) analysis. Results. The effectiveness indicators of doses of Madison and Reverson were: in horses m = 200 kg – a dose of Madison 20 mL/head, immobilization after 22 min, in horses m = 300 kg, a dose of Madison – 25 mL/head, immobilization in 20–22 min. The Reverson antidote was applied in the following doses: animal m = 200 kg – a dose of Reverson 5–15 mL/goal, cessation of the sedative effect – 12 min; animal m = 300 kg – a dose of Reverson 5–15 mL/goal, cessation of the sedative effect – 18 min. Observation of the effect of the drugs did not reveal any negative side effects. Cytogenetic analysis determined the karyotype norm of somatic cells with 2n = 66 chromosomes. Genomic disorders, aneuploidy, accounted for 6.7%, polyploidy – 1.3 %. Structural violations (chromosomal and chromatid breaks) were not detected. The results of the micronucleus test: the share of lymphocytes with a micronucleus – 3.0 ‰, binuclear lymphocytes – 2.3 ‰, mitotic index – 7.7 ‰. Genetic indicators of the population of Przewalski’s horses according to ISSR markers: when using (GA)9C as a primer, microsatellite repeats of polymorphic loci were not found, and according to primer (GAG)6C – 50 % of polymorphic loci. The main indicators of genetic diversity, with the help of ISSR markers: the share of polymorphic loci was 25 %, the average gene diversity per locus – 0.39, the Shannon–Wiener information index – 2.5. Conclusions. No negative side effects occur when Madison and Reverson drugs are used to immobilize Przewalski’s horses. According to the results of cytogenetic analy­sis, the stability of the karyotype of the studied animals was established. The study of genetic polymorphism of the horse population by ISSR markers (AG)9C and (GAG)6C indicates a high degree of genetic consolidation. All tested animals are relatively safe according to the revealed intra-population genetic diversity.

Quantity, variability and correlation of sex and thyroid hormones in sheep of Romanov breed with biochemical, physicochemical and cytogenetic parameters

A comprehensive assessment of the physiological state of animals should include a study of hormone levels and their correlations with different hematological, biochemical, physicochemical and cytogenetic parameters. Hormonal status is an important integral indicator reflecting the general condition of the organism and the adaptive capabilities of animals. The average values, variability and reference intervals of sex and thyroid hormones in sheep of Romanov breed in Western Siberia were determined. No significant correlations were found between the levels of the studied hormones in the blood serum. Average and high correlations of various directions were found between the hormone levels with some biochemical, physicochemical and cytogenetic parameters. Thus, triiodothyronine correlated positively with the number of leukocytes (r=0.441) and urea (r=0.509), but negatively with conjugated bilirubin (r=–0.558). Thyroid hormones were largely associated with biochemical parameters. Sex hormones were associated in many cases with the level of heavy metals in some organs of sheep. Thus, estradiol was positively associated with the copper content in the heart (r=0.463) and liver (r=0.439), but negatively with the lead level in the lungs (r=–0.499). Negative correlations were found between the thyroid hormone content and some indices of somatic chromosomal instability. Thus, the level of triiodothyronine negatively correlated with the frequency of chromosome aberrations (r=–0.527), and thyroxine with the frequency of chromosome breaks (r=–0.639).

Investigating the effects of the ARG258HIS mutation on RAD51C in inherited Fanconi Anemia and cancer disease

Fanconi anemia is a rare chromosomal instability disorder associated with developmental abnormalities, bone marrow failure, and a heightened susceptibility to leukemia and other cancers. It is an autosomal recessive genetic disorder, necessitating both parents to carry the faulty gene. Diagnostic methods include blood tests, chromosome breakage assessments, and genetic testing. While there is no cure, treatments encompass blood transfusions, bone marrow transplants, and gene therapy, with patients requiring regular check-ups, supportive care, and cancer screening to enhance their quality of life. In this study, we identify a specific substitution (R258H) targeting the crucial binding site of the alpha-helix region in RAD51C. This substitution induces structural disorder in distinct regions, as indicated by the near absence of electron density for multiple amino acids. Intriguingly, these disordered regions do not follow a continuous sequence from the mutation site and extend across domain boundaries. We utilized computational prediction algorithms and Molecular Dynamics (MD) simulations to model RAD51C and its mutation (R258H) structurally. These simulations highlighted alterations in conformational dynamics, the Free Energy Landscape (FEL), and intrinsic molecular motions induced by the mutation, suggesting structural destabilization that could disrupt its function. This observed destabilization in RAD51C due to mutations offers valuable insights that may serve as diagnostic markers for individuals carrying these mutations, particularly in Fanconi anemia.

Profound synthetic lethality between SMARCAL1 and FANCM

DNA replication stress is a threat to genome integrity. The large SNF2-family of ATPases participates in preventing and mitigating DNA replication stress by employing their ATP-driven motor to remodel DNA or DNA-bound proteins. To understand the contribution of these ATPases in genome maintenance, we undertook CRISPR-based synthetic lethality screens in human cells with three SNF2-type ATPases: SMARCAL1, ZRANB3, and HLTF. Here, we show that SMARCAL1 displays a profound synthetic-lethal interaction with FANCM, another ATP-dependent translocase involved in DNA replication and genome stability. Their combined loss causes severe genome instability that we link to chromosome breakage at loci enriched in simple repeats, which are known to challenge replication fork progression. Our findings illuminate a critical genetic buffering mechanism that provides an essential function for maintaining genome integrity.

A case of indeterminate cell histiocytosis with ETV3-NCOA2 translocation.

Indeterminate cell histiocytosis (ICH) is a rare histiocytic disorder characterized by a proliferation of CD1a+ and CD207/langerin- cells. Recent molecular analyses have identified ETV3-NCOA2 translocation as a possible aetiopathogenesis of ICH. Herein, we describe the first Japanese case of ICH with ETV3-NCOA2 translocation. A 79-year-old Japanese man presented with a 1-year history of pruritic erythematous papules and nodules on his trunk and extremities. Histological examination revealed a dense and diffuse sheets-like infiltration of medium-sized histiocyte-like cells from the epidermis to the deep dermis. Immunohistochemically, the atypical cells were positive for CD1a but negative for CD207/langerin. Fluorescence insitu hybridization using NCOA2 break-apart probes confirmed a chromosomal break occurring on NCOA2 monoallele in the tumor cells. Furthermore, ETV3 exon 4-NCOA2 exon 14 translocation was identified in formalin-fixed paraffin-embedded skin samples using reverse transcription polymerase chain reaction and subsequent direct DNA sequencing. He also presented with interspersed eczematous plaques on his trunk and reactive dermatopathic lymphoadenopathy without any infiltration of ICH. He was treated with topical corticosteroids and narrowband UVB phototherapy. Four months later, his ICH skin eruptions, eczematous plaques, and lymphoadenopathy gradually regressed. Our case supports the notion that the detection of ETV3-NCOA2 translocation can be useful for diagnosis of ICH.

Key insights into cannabis-cancer pathobiology and genotoxicity.

Whilst mitochondrial inhibition and micronuclear fragmentation are well established features of the cannabis literature mitochondrial stress and dysfunction has recently been shown to be a powerful and direct driver of micronucleus formation and chromosomal breakage by multiple mechanisms. In turn genotoxic damage can be expected to be expressed as increased rates of cancer, congenital anomalies and aging; pathologies which are increasingly observed in modern continent-wide studies. Whilst cannabinoid genotoxicity has long been essentially overlooked it may in fact be all around us through the rapid induction of aging of eggs, sperm, zygotes, foetus and adult organisms with many lines of evidence demonstrating transgenerational impacts. Indeed this multigenerational dimension of cannabinoid genotoxicity reframes the discussion of cannabis legalization within the absolute imperative to protect the genomic and epigenomic integrity of multiple generations to come.

Fanconi Anemia: Challenges in Diagnosis and Management-A Case Series Report.

Fanconi anemia (FA) is a rare inherited disorder characterized by congenital abnormalities, progressive bone marrow failure, and a predisposition to malignancies. Detecting FA can be challenging, as it involves identifying increased chromosomal sensitivity to DNA cross-linking agents and detecting causative genetic variants via genome sequencing. We report two cases of siblings with FA, both confirmed to have the FANCD2 variant through whole-exome sequencing (WES). The first patient presented with epistaxis, petechiae, ecchymosis, and lower limb edema. The second patient exhibited epistaxis, diabetes, developmental delay, and physical abnormalities. Interestingly, both patients had negative results on the initial chromosomal breakage test with mitomycin C, a commonly used diagnostic tool for FA. However, further investigation with WES revealed the presence of the FANCD2 variant, confirming the FA diagnosis. This case report highlights the challenges in diagnosing FA, particularly when initial screening tests yield negative results. Molecular genetic testing, such as WES, can provide a definitive diagnosis and guide appropriate management strategies. Early and accurate diagnosis is crucial for improving outcomes in individuals with this potentially fatal illness, as promising advancements in treatments such as hematopoietic stem cell transplantation and gene therapy offer hope for addressing FA.

Cytogenetic and <i>ISSR</i>-Markers Polymorphism in the Population of Local Ukrainian Lebedyn Cows

Preservation of the fund of local breeds of agricultural animals, which are breeding material for the creation of new ones and the improvement of existing ones, meets the requirements of the FAO - the protection of biological diversity. The study of the genetic structure of cows of the local Lebedyn breed, which was bred in Ukraine, with the use of cytogenetic and molecular genetic methods, is aimed at establishing information about the structure of the gene pool of these animals and the uniqueness of their genotype. Cytogenetic monitoring showed that the modal number of chromosomes corresponded to the species norm and was 2n=60, no constitutional abnormalities in the form of Robertsonian translocations were detected, the average frequency of genomic disorders (aneuploidy) was 10,2±2,10%, polyploidy was not manifested. structural disorders (chromosomal breaks) accounted for 3,1±1,88% and asynchronous separation of the centromeric regions of chromosomes – 0,8±0,10%. The average share of cytogenetic parameters of cells was determined: lymphocytes with micronucleus – 3,6±0,61‰, binucleus lymphocytes – 4,3±0,97‰ and mitotic index – 3,7±1,20‰. An analysis of the genetic structure of the local, small-numbered Lebedyn cattle breed of Ukraine was carried out using 8 ISSR-systems. All 8 microsatellite primers showed high efficiency. ISSR labeling revealed 88 amplified DNA fragments, of which only 18 were polymorphic. The total share of polymorphic loci was 25,45%. 11 species-specific loci for (ACC)6G, 5 loci for (CTC)6C, 10 for (GAG)6C, 7 for (GA)6CC, 10 for (AG)8CG, 9 for (AG)8CA, 13 for (GA)9C and 14 for (AG)9C. It was established that the studied animals were characterized by karyotype stability, reduced sensitivity to mutagenic factors of various nature, absence of inbreeding depression and reproductive isolation.