DNA Sequence Research Articles

Analysis of the genetic structure of populations of the terrestrial mollusk <i>Caucasotachea vindobonensis</i> (Helicidae) in conditions at the eastern border of the range using microsatellite markers

BACKGROUND: Assessing the genetic structure of populations of rare and vulnerable species provides useful information for developing conservation strategies. AIM: The aim of the study was to study the genetic structure of Caucasotachea vindobonensis populations in the south of the Central Russian Upland using SSR markers. MATERIALS AND METHODS: Genetic structure of the populations was studied using eight microsatellite markers, first identified by the authors for the species under study. Fragment analysis of PCR products was carried out on an automatic capillary DNA sequencer Nanophore 05 (Russia). A total of 498 individuals from 24 populations were studied. RESULTS: A total of 59 alleles were isolated in the eight studied SSR loci, of which 21 (36%) turned out to be private. At the same time, private alleles were found in eleven studied populations, which is 46% of their total number. According to the data obtained, the effective number of alleles (Ae) averaged 1.6 ± 0.06, the Shannon index (I) was 0.45 ± 0.03, and the level of expected heterozygosity (He) was 0.27 ± 0.021. A high level of spatial subdivision of population gene pools was noted (Fst = 0.47 ± 0.08) with a fairly low level of gene flow (Nm = 1.15 ± 0.91). PCA analysis showed that the populations of the central and eastern parts of the south of the Central Russian Upland form a closely related group, different from other populations of the region. Calculation of the effective abundance using the LD method showed that Ne varies in different groups of snails from 0.6 to infinity. CONCLUSIONS: Populations of C. vindobonensis in the south of the Central Russian Upland live in conditions of significant isolation, as evidenced by the high degree of differentiation of the studied groups. The analysis of principal components based on genetic distances according to Nei and Wright’s F-statistics indicate a pronounced division of populations in the study area into two clusters, which is probably associated with the historical features of landscape formation. Calculation of effective numbers indicates the high viability of the majority of the studied populations. At the same time, some groups of snails are clearly in a depressed state, which is reflected in low levels of genetic diversity and their effective size.

Direct Zeptomole Detection of RNA Biomarkers by Ultrabright Fluorescent Nanoparticles on Magnetic Beads.

Nucleic acids are important biomarkers in cancer and viral diseases. However, their ultralow concentration in biological/clinical samples makes direct target detection challenging, because it leads to slow hybridization kinetics with the probe and its insufficient signal-to-noise ratio. Therefore, RNA target detection is done by molecular (target) amplification, notably by RT-PCR, which is a tedious multistep method that includes nucleic acid extraction and reverse transcription. Here, a direct method based on ultrabright dye-loaded polymeric nanoparticles in a sandwich-like hybridization assay with magnetic beads is reported. The ultrabright DNA-functionalized nanoparticle, equivalent to ≈10 000 strongly emissive rhodamine dyes, is hybridized with the magnetic bead to the RNA target, providing the signal amplification for the detection. This concept (magneto-fluorescent sandwich) enables high-throughput detection of DNA and RNA sequences of varied lengths from 48 to 1362nt with the limit of detection down to 0.3 fm using a plate reader (15 zeptomoles), among the best reported for optical sandwich assays. Moreover, it allows semi-quantitative detection of SARS-CoV-2 viral RNA directly in clinical samples without a dedicated RNA extraction step. The developed technology, combining ultrabright nanoparticles with magnetic beads, addresses fundamental challenges in RNA detection; it is expected to accelerate molecular diagnostics of diseases.

Re-engineered guide RNA enables DNA loops and contacts modulating repression in E. coli.

RNA serves as information media as well as molecular scaffold in nature and synthetic systems. The single guide RNA (sgRNA) widely applied in CRISPR techniques exemplifies both functions, with a guide region bearing DNA base-pairing information, and a structural motif for Cas9 protein scaffolding. The scaffold region has been modified by fusing RNA aptamers to the tetra-stem loop. The guide region is typically not regarded as a pluggable module as it encodes the essential function of DNA sequence recognition. Here, we investigate a chimera of two sgRNAs, with distinct guide sequences joined by an RNA linker (dgRNA), regarding its DNA binding function and loop induction capability. First, we studied the sequence bi-specificity of the dgRNA and discovered that the RNA linker allows distal parts of double-stranded DNA to be brought into proximity. To test the activity of the dgRNA in organisms, we used the LacZ gene as a reporter and recapitulated the loop-mediated gene inhibition by LacI in E. coli. We found that the dgRNA can be applied to target distal genomic regions with comparable levels of inhibition. The capability of dgRNA to induce DNA contacts solely requires dCas9 and RNA, making it a minimal system to remodel chromosomal conformation in various organisms.

First record of ectoparasites (Phthiraptera and Acari) from the Andean condor (Vultur gryphus) in Colombia.

Several species of ectoparasites, including chewing lice and mites are closely associated with their hosts. The Andean condor (Vultur gryphus) is globally listed as vulnerable by the IUCN and its population has been steadily declining in recent decades suggesting a potential extinction of associated entomofauna. The purpose of this study was to record the species of ectoparasites infesting three individuals of Andean condor found dead in the 'Páramo del Almorzadero' Santander Department, Northeastern Colombia. One juvenile (male) and two adults (male and female) Andean condors received for necropsy were carefully examined for ectoparasite infestation. Specimens were collected and preserved in ethanol (70%) for taxonomic studies. Morphologic identification and morphometric records were made under light microscopy. Some specimens were also prepared for scanning electron microscopy and others were subjected to DNA extraction to amplify and obtain sequences of the cytochrome-C oxidase subunit I (COI) gene for phylogenetic analyses. Lice were collected from the juvenile condor and the adult female and identified as Falcolipeurus assesor (Phthiraptera: Ischnocera) in the juvenile condor (8 females, 19 males and 8 nymphs) and the adult (1 female); Colpocephalum trichosum (Phthiraptera: Amblycera) in the juvenile (19 females, 24 males and 1 nymph) and the adult (2 females, 2 males and 3 nymphs); and Cuculiphilus zonatus (Phthiraptera: Amblycera) in the juvenile (40 females, 43 males and 15 nymphs) and the adult (1 male and 2 nymphs). Moreover, one mite collected from the juvenile condor was identified as Ancyralges cathartinus (Acari: Astigmata) (1 female). Morphometric data was obtained for the adult stages of F. assesor (6 females and 13 males), C. trichosum (9 females and 9 males) and C. zonatus (10 females and 10 males). We obtained the first DNA sequences of COI for F. assessor, and C. trichosum, where phylogenetic tree analysis showed that F. assessor is more closely related to Falcolipeurus marginalis, and C. trichosum to Colpocephalum kelloggi. This represents the first record of parasites in Andean condor from Colombia and contributes to the knowledge of chewing lice and mites associated with an endemic and endangered bird species. Further studies on Andean condor ectoparasites should be focused on documenting host-parasite interactions and potential health impacts in these wild birds.

Seamless site-directed mutagenesis in complex cloned DNA sequences using the RedEx method.

Seamless site-directed mutagenesis is an important technique for studying protein functions, tuning enzyme catalytic activities and modifying genetic elements in multiple rounds because it can insert, delete or substitute nucleotides, DNA segments or even entire genes at the target site without introducing any unwanted change. To facilitate seamless site-directed mutagenesis in large plasmids and bacterial artificial chromosomes (BACs) with repetitive sequences, we recently developed the RedEx strategy. Compared with previous methods, our approach achieves the recovery of correct recombinants with high accuracy by circumventing unwanted recombination between repetitive sequences. RedEx readily yields more than 80% accuracy in seamless DNA insertion and deletion in large multimodular polyketide synthase gene clusters, which are among the most difficult targets due to the large number of repetitive DNA sequences in modules encoding almost identical enzymes. Here we present the RedEx method by describing in detail the seamless site-directed mutagenesis in a BAC vector. Overall, the process includes three parts: (1) insertion of the RedEx cassette containing the desired mutation together with selection-counterselection markers flanked by unique restriction sites and 20-bp overlapping sequences into the target site by recombineering, (2) removal of the selection-counterselection markers in the BAC by restriction digestion and (3) circularization of the linear BAC by exonuclease-mediated in vitro DNA annealing. This protocol can be performed within 3 weeks and will enable researchers with DNA cloning experience to master seamless site-directed mutagenesis to accelerate their research.

Joint and Individual Mitochondrial DNA Variation and Cognitive Outcomes in Black and White Older Adults.

Mitochondrial dysfunction manifests in neurodegenerative diseases and other age-associated disorders. In this study, we examined variation in inherited mitochondrial DNA (mtDNA) sequences in Black and White participants from two large aging studies to identify variants related to cognitive function. Participants included self-reported Black and White adults aged ≥ 70 years in the Lifestyle Interventions and Independence for Elders (LIFE; N=1319) and Health Aging and Body Composition (Health ABC; N=7888) studies. Cognitive function was measured by the digit-symbol substitution test (DSST), and the Modified Mini-Mental State Exam (3MSE) at baseline and over follow-up in LIFE (3.6 years) and Health ABC (10 years). We examined joint effects of multiple variants across 16 functional mitochondrial regions with cognitive function using a sequence kernel association test. Based on these results, we prioritized meta-analysis of common variants in Black and White participants using mixed effects models. A Bonferroni adjusted p-value of <0.05 was considered statistically significant. Joint variation in subunits ND1, ND2, and ND5 of Complex I, 12S RNA, and hypervariable region (HVR) were significantly associated with DSST and 3MSE at baseline. In meta-analyses among Black participants, variant m.4216T>C, ND1 was associated with a faster decline in 3MSE, and variant m.462C>T in the HVR was associated with a slower decline in DSST. Variant m.5460G>C, ND2 was associated with slower and m.182C>T in the HVR was associated with faster decline in 3MSE in White participants. Among Black and White adults, oxidative phosphorylation Complex I variants were associated with cognitive function.

Insular environment-dependent introgression from an arid-grassland orchid to a wetland orchid on an oceanic island

Abstract Adaptive introgression plays a vital role in allowing recipient species to adapt and colonize new environments. However, our understanding of such environment-dependent introgressions is primarily limited to specific plant taxa in particular settings. In Japan, two related orchid species, the autonomously self-pollinating Pogonia minor and the outcrossing Pogonia japonica, typically inhabit dry grasslands and wetlands, respectively. Intriguingly, an island ecotype of P. japonica exists in arid, wind-swept, open sites on volcanic mountain slopes on Kozu Island, in the oceanic Izu Islands. To investigate potential introgression and its implications between P. japonica and P. minor on Kozu Island, we applied a comprehensive approach that included examining morphological traits, genome-wide SNP data, and plastid DNA sequences. We also examined the breeding systems of these species on Kozu Island through artificial pollination experiments to determine if introgression from P. minor has endowed the P. japonica ecotype with selfing capabilities. Extensive sampling on Kozu Island revealed that all P. japonica specimens exhibit signs of introgression from P. minor, suggesting the absence of pure P. japonica populations on the island. Furthermore, the chloroplast haplotypes of the insular P. japonica ecotype consistently match those of P. minor, indicating a predominantly asymmetrical initial hybridization with P. minor acting mainly as the maternal parent in the formation of F1 hybrids. Despite the advantages of self-fertilization in isolated environments, the insular P. japonica does not exhibit autogamy. Consequently, the scarcity of moist habitats, rather than selection pressure for selfing, likely contributes to the observed widespread introgression. Our study strongly suggests that the arid-environment-adapted P. minor has introgressed into the insular ecotype of P. japonica, enabling its successful colonization of arid volcanic mountain slopes of the oceanic island.

Congenital anomalies of the kidney and urinary tract

Congenital Anomalies of the Kidney and Urinary Tract (CAKUT) refer to a range of conditions that affect the kidney and urinary tract. These anomalies can be severe, such as kidney agenesis, or milder, such as vesicoureteral reflux. CAKUT affects over 1% of live births and accounts for 40–50% of cases of chronic kidney failure in children. The pathogenesis of CAKUT is caused by various environmental, genetic, and epigenetic factors that disrupt normal nephrogenesis. Environmental factors that can lead to CAKUT include maternal diabetes, obesity, malnutrition, alcohol consumption, or medications affecting kidneys development. Genetic factors can cause an imbalance in the metanephros and the ureteric bud interaction. Defects in specific genes such as PAX2, TBX18, NRIP1, REX, SIX2, BMP4, and chromosome 17 cause CAKUT. Over 50 genes have been identified as the root cause of this condition, with monogenetic variants causing up to 20% of all cases. CAKUTs can be diagnosed through fetal ultrasonography, but some anomalies may remain undetected. GWASs, Next Generation Sequencing for targeted and whole exome DNA sequencing may provide additional diagnostic methods. This review article highlights some the leading factors that cause CAKUT, which adversely affects kidney development and urinary tract function.

Design and expression of a chimeric recombinant antigen (SsIR-Ss1a) for the serodiagnosis of human strongyloidiasis: Evaluation of performance, sensitivity, and specificity.

The sensitivity of parasitological and molecular methods is unsatisfactory for the diagnosis of strongyloidiasis, and serological techniques are remaining as the most effective diagnostic approach. The present study aimed to design and produce a chimeric recombinant antigen from Strongyloides stercoralis immunoreactive antigen (SsIR) and Ss1a antigens, using immune-informatics approaches, and evaluated its diagnostic performance in an ELISA system for the diagnosis of human strongyloidiasis. The coding sequences for SsIR and Ss1a were selected from GenBank and were gene-optimized. Using bioinformatics analysis, the regions with the highest immunogenicity that did not overlap with other parasite antigens were selected. The chimeric recombinant antigen SsIR- Ss1a, was constructed. The solubility and physicochemical properties of the designed construct were analyzed and its tertiary structures were built and evaluated. The construct was expressed into the pET-23a (+) expression vector and the optimized DNA sequences of SsIR-Ss1a (873 bp) were cloned into competent E. coli DH5α cells. Diagnostic performances of the produced recombinant antigen, along with a commercial kit were evaluated in an indirect ELISA system, using a panel of sera from strongyloidiasis patients and controls. The physicochemical and bioinformatics evaluations revealed that the designed chimeric construct is soluble, has a molecular with of 35 KDa, and is antigenic. Western blotting confirmed the immunoreactivity of the produced chimeric recombinant antigen with the sera of strongyloidiasis patients. The sensitivity and specificity of the indirect ELISA system, using the produced SsIR-Ss1a chimeric antigen, were found to be 93.94% (95% CI, 0.803 to 0.989) and 97.22% (95% CI, 0.921 to 0.992) respectively. The preliminary findings of this study suggest that the produced SsIR-Ss1a chimeric antigen shows promise in the diagnosis of human strongyloidiasis. However, these results are based on a limited panel of samples, and further research with a larger sample size is necessary to confirm its accuracy. The construct has potential as an antigen in the ELISA system for the serological diagnosis of this neglected parasitic infection, but additional validation is required.

MMR status of colorectal carcinomas at a tertiary cancer care centre in Central India

Microsatellite instability (MSI) and mismatch repair (MMR) deficiency are important biomarkers in colorectal cancer (CRC) that have clinical implications for patient management and treatment. MMR deficiency can lead to MSI, which is characterized by alterations in the length of microsatellite DNA sequences. Clinical applications of MMR deficiency in colorectal adenocarcinoma are as a prognostic marker as well as Predictive marker for adjuvant chemotherapy and immunotherapy. To assess the MMR status of colorectal adenocarcinomas.: This was a retrospective study of 127 colorectal adenocarcinomas cases. All the samples were either biopsies or surgically resected tumor tissues from patients of Carcinoma Colon and rectum. Immunohistochemistry was performed on Roche Ventana Benchmark XT autostainer.: MLH-1, PMS2, MSH2 and MSH6 expression was retained in the tumor cells in 106 cases and it was lost in 21 cases. Among various clinicopathological variables, tumor site and AJCC pStage were found to be significantly associated with dMMR tumors. Patients of colorectal adenocarcinomas were benefited by MMR testing as it influenced the adjuvant treatment in all Stage IIA cases as well as all metastatic cases. Incorporating MMR testing into routine clinical practice can help optimize patient management and treatment strategies in CRC.

Molecular analysis of persistent and recurrent Barrett's esophagus in the setting of endoscopic therapy.

Early neoplastic progression of Barrett's esophagus (BE) is often treated with endoscopic therapy. While effective, some patients are refractory to therapy or recur after apparent eradication of the BE. The goal of this study was to determine whether genomic alterations within the treated BE may be associated with persistent or recurrent disease. We performed DNA sequencing on pre-treatment esophageal samples from 45 patients who were successfully treated by endoscopic therapy and did not recur as well as pre- and post-treatment samples from 40 patients who had persistent neoplasia and 21 patients who had recurrent neoplasia. The genomic alterations were compared between groups. The genomic landscape was similar between all groups. Patients with persistent disease were more likely to have pre-treatment alterations involving the receptor tyrosine kinase pathway (p=0.01), amplifications of oncogenes (p=0.01), and deletions of tumor suppressor genes (p=0.02). These associations were no longer significant after adjusting for patient age and BE length. Over half of patients with persistent (52.5%) or recurrent (57.2%) disease showed pre- and post-treatment samples that shared at least 50% of their driver mutations. Pre-treatment samples were genomically similar between those who responded to endoscopic therapy and those who had persistent or recurrent disease, suggesting there is not a strong genomic component to treatment response. While it was expected to find shared driver mutations in pre- and post-treatment samples in patients with persistent disease, the finding that an equal number of patients with recurrent disease also showed this relation suggests that many recurrences represent undetected minimal residual disease.

Addressing Technical Pitfalls in Pursuit of Molecular Factors That Mediate Immunoglobulin Gene Regulation.

The expressed Ab repertoire is a critical determinant of immune-related phenotypes. Ab-encoding transcripts are distinct from other expressed genes because they are transcribed from somatically rearranged gene segments. Human Abs are composed of two identical H and L chain polypeptides derived from genes in IGH locus and one of two L chain loci. The combinatorial diversity that results from Ab gene rearrangement and the pairing of different H and L chains contributes to the immense diversity of the baseline Ab repertoire. During rearrangement, Ab gene selection is mediated by factors that influence chromatin architecture, promoter/enhancer activity, and V(D)J recombination. Interindividual variation in the composition of the Ab repertoire associates with germline variation in IGH, implicating polymorphism in Ab gene regulation. Determining how IGH variants directly mediate gene regulation will require integration of these variants with other functional genomic datasets. In this study, we argue that standard approaches using short reads have limited utility for characterizing regulatory regions in IGH at haplotype resolution. Using simulated and chromatin immunoprecipitation sequencing reads, we define features of IGH that limit use of short reads and a single reference genome, namely 1) the highly duplicated nature of the DNA sequence in IGH and 2) structural polymorphisms that are frequent in the population. We demonstrate that personalized diploid references enhance performance of short-read data for characterizing mappable portions of the locus, while also showing that long-read profiling tools will ultimately be needed to fully resolve functional impacts of IGH germline variation on expressed Ab repertoires.

NQuack: An R package for predicting ploidal level from sequence data using site‐based heterozygosity

AbstractPremiseTraditional methods of ploidal‐level estimation are tedious; using DNA sequence data for cytotype estimation is an ideal alternative. Multiple statistical approaches to leverage sequence data for ploidy inference based on site‐based heterozygosity have been developed. However, these approaches may require high‐coverage sequence data, use inappropriate probability distributions, or have additional statistical shortcomings that limit inference abilities. We introduce nQuack, an open‐source R package that addresses the main shortcomings of current methods.Methods and ResultsnQuack performs model selection for improved ploidy predictions. Here, we implement expectation maximization algorithms with normal, beta, and beta‐binomial distributions. Using extensive computer simulations that account for variability in sequencing depth, as well as real data sets, we demonstrate the utility and limitations of nQuack.ConclusionsInferring ploidy based on site‐based heterozygosity alone is difficult. Even though nQuack is more accurate than similar methods, we suggest caution when relying on any site‐based heterozygosity method to infer ploidy.

Defined folding pattern of poly(rG) supports inherent ability to encode biological information.

The RNA World hypothesis posits that RNA can represent a primitive life form by reproducing itself and demonstrating catalytic activity. However, this hypothesis is incapable of addressing several major origin-of-life (OoL) questions. A recently described paradox-free alternative OoL hypothesis, the Quadruplex (G4) World, is based on the ability of poly(dG) to fold into a stable architecture with an unambiguous folding pattern using G-tetrads as building elements. Because of the folding pattern of three G-tetrads and single-G loops, dG15 is programmable and has the capability to encode biological information. Here, we address two open questions of the G4 World hypothesis: (1) Does RNA follow the same folding pattern as DNA? (2) How do stable quadruplexes evolve into the present-day system of information transfer, which is based on Watson-Crick base pair complementarity? To address these questions, we systematically studied the thermodynamic and optical properties of both DNA and RNA G15- and G3T (GGGTGGGTGGGTGGG)-derived sequences. Our study revealed that similar to DNA sequences, RNAs adopt quadruplexes with only three G-tetrads. Thus, both poly(dG) and poly(rG) possess inherent ability to fold into 3D quadruplex architecture with strictly defined folding pattern. The study also revealed that despite high stability of both DNA and RNA quadruplexes, they are vulnerable to single-nucleotide substitutions, which drop the thermal stability by ~40°C and can facilitate introduction of the complementarity principle into the G4 World.

Drawing mitochondrial genomes with circularMT.

Mitochondrial DNA sequences are used extensively in phylogeographic and phylogenetic studies for a wide range of organisms. With the advent of low-cost, high throughput 'next generation' DNA sequencing, and user-friendly bioinformatics pipelines for generating and annotating whole mitochondrial genome assemblies, the analysis of whole mitochondrial genomes has become an important component of phylogenomic studies for taxa with high species diversity but limited coverage for other genomic resources. An important step in characterizing de novo mitochondrial genome assemblies is to evaluate and describe structural rearrangements relative to reference taxa. Accessible tools are needed to help visualize gene and noncoding feature complement, their order and strand orientation. However, there are few dedicated applications that generate high quality genome diagrams. Here we present circularMT and circularMT-console that allow users to create highly customizable, publication quality images, of linear and circular mitochondrial genome maps, either individually, or integrated into an analysis pipeline. Both applications are implemented in C#, with binaries, source code and user guides available on GitHub (https://github.com/msjimc/circularMT). An archive of the published version is available on Zenodo (https://zenodo.org/records/10912319). This paper has no supplementary data.

DNA barcoding of epiphytic orchids for species level identification

ABSTRACT DNA barcoding has proven to be an effective technique for molecular-level identification in plants, including orchids which exhibit a great degree of genetic variability but show almost identical morphological features in closely related genera. The present study was conducted to evaluate the effectiveness of universal chloroplast gene markers, matK (maturase K gene) and rbcL (ribulose-1, 5-bisphosphate carboxylase/oxygenase large subunit) as DNA barcodes to identify Aerides multiflora and Rhynchostylis retusa at species level. The DNA sequences from different genotypes of both the orchid species collected from natural populations were compared with database sequences of orchid species using BLAST and maximum likelihood phylogenetic tree. For A. multiflora samples, the phylogenetic analysis revealed a highest of 99.4% sequence percentage alignment (for matK region) and 99.39% percent identity with sequences belonging to A. multiflora accessions. In the case of R. retusa, the matK region showed a highest sequence percentage alignment of 99.87% with the accessions of R. retusa, while the highest per cent identity for the rbcL region was 100% that matched with accessions of R. retusa, C. peduncularis and A. praemorsa. The study confirms the reliability of matK and rbcL markers for authentication of the two orchid species under the current investigation.

New Cortinariaceae species associated with Dicymbe, Aldina, and Pakaraimaea in Guyana

ABSTRACT Species of the ectomycorrhizal (ECM) family Cortinariaceae (Agaricales, Agaricomycetes, Basidiomycota) have long been considered impoverished or absent from lowland tropical rainforests. Several decades of collecting in forests dominated by ECM trees in South America’s Guiana Shield is countering this view, with discovery of numerous Cortinariaceae species. To date, ~12 morphospecies of this family have been found in the central Pakaraima Mountains of Guyana. Here, we describe three of these as new species of Cortinarius and two as new species of Phlegmacium from forests dominated by the ECM tree genera Dicymbe (Fabaceae subfam. Detarioideae), Aldina (Fabaceae subfam. Papilionoideae), and Pakaraimaea (Cistaceae). Macromorphological, micromorphological, habitat, and DNA sequence data are provided for each new species.

Pharmacotherapeutic Considerations on Telomere Biology: The Positive Effect of Pharmacologically Active Substances on Telomere Length

Telomeres are part of chromatin structures containing repeated DNA sequences, which function as protective caps at the ends of chromosomes and prevent DNA degradation and recombination, thus ensuring the integrity of the genome. While telomere length (TL) can be genetically inherited, TL shortening has been associated with ageing and multiple xenobiotics and bioactive substances. TL has been characterised as a reliable biomarker for the predisposition to developing chronic pathologies and their progression. This narrative review aims to provide arguments in favour of including TL measurements in a complex prognostic and diagnostic panel of chronic pathologies and the importance of assessing the effect of different pharmacologically active molecules on the biology of telomeres. Medicines used in the management of cardiovascular diseases, diabetes, schizophrenia, hormone replacement therapy at menopause, danazol, melatonin, and probiotics have been studied for their positive protective effects against TL shortening. All these classes of drugs are analysed in the present review, with a particular focus on the molecular mechanisms involved.

Diversity of Kordyana species (Brachybasidaceae) on Commelinaceae in Australia

The identity and diversity of Kordyana species on three native species of Commelinaceae in Australia were studied following surveys in 2020–2022 for Kordyana brasiliensis, which had been deliberately released as a biocontrol agent for the environmental weed Tradescantia fluminensis. Three new species of Kordyana are described from Australia based on DNA sequence analysis of the ITS and LSU rDNA regions, morphology, host associations, and geographic distributions. Two new species, Kordyana spectabilis on Aneilema acuminatum and Kordyana luteoalba on Pollia crispata, occur in shaded rainforest habitats in eastern Australia. The third new species, Kordyana occidentalis on Commelina ensifolia, occurs in forests and woodlands of the Kimberley region of Western Australia. Morphological descriptions are provided for these three new species of Kordyana as well as for the conidial stage of K. brasiliensis.

Rare de novo damaging DNA variants are enriched in attention-deficit/hyperactivity disorder and implicate risk genes

Research demonstrates the important role of genetic factors in attention-deficit/hyperactivity disorder (ADHD). DNA sequencing of families provides a powerful approach for identifying de novo (spontaneous) variants, leading to the discovery of hundreds of clinically informative risk genes for other childhood neurodevelopmental disorders. This approach has yet to be extensively leveraged in ADHD. We conduct whole-exome DNA sequencing in 152 families, comprising a child with ADHD and both biological parents, and demonstrate a significant enrichment of rare and ultra-rare de novo gene-damaging mutations in ADHD cases compared to unaffected controls. Combining these results with a large independent case-control DNA sequencing cohort (3206 ADHD cases and 5002 controls), we identify lysine demethylase 5B (KDM5B) as a high-confidence risk gene for ADHD and estimate that 1057 genes contribute to ADHD risk. Using our list of genes harboring ultra-rare de novo damaging variants, we show that these genes overlap with previously reported risk genes for other neuropsychiatric conditions and are enriched in several canonical biological pathways, suggesting early neurodevelopmental underpinnings of ADHD. This work provides insight into the biology of ADHD and demonstrates the discovery potential of DNA sequencing in larger parent-child trio cohorts.