The Sequence Alignment/Map format and SAMtools

Robust prediction of synthetic gRNA activity and cryptic DNA repair by disentangling cellular CRISPR cleavage outcomes

The ability to robustly predict guide RNA (gRNA) activity is a long-standing goal for CRISPR applications, as it would reduce the need to pre-screen gRNAs. Quantification of formation of short insertions and deletions (indels) after DNA cleavage by transcribed gRNAs has been typically used to measure and predict gRNA activity. We evaluate the effect of chemically synthesized Cas9 gRNAs on different cellular DNA cleavage outcomes and find that the activity of different gRNAs is largely similar and often underestimated when only indels are scored. We provide a simple linear model that reliably predicts synthetic gRNA activity across cell lines, robustly identifies inefficient gRNAs across different published datasets, and is easily accessible via online genome browser tracks. In addition, we develop a homology-directed repair efficiency prediction tool and show that unintended large-scale repair events are common for Cas9 but not for Cas12a, which may be relevant for safety in gene therapy applications.

Population Genomics and Morphology Provide Insights into the Conservation and Diversity of Apis laboriosa

In recent decades, honeybee populations have declined, dramatically owing to destructive honey harvesting practices and the loss of foraging grounds and nesting sites. Among them, Apis laboriosa Smith, 1871 (Hymenoptera, Apidae), an important pollinator species found in the Himalayan region, holds significant economic and ecological value. However, conservation efforts and intraspecific taxonomic studies regarding it have been rather limited, and thus its full geographic range remains elusive. This study is the first to research A. laboriosa in Sichuan. Through a systematic study integrating morphological feature analysis and genomic data, the following conclusions are drawn. Whole-genome resequencing data analysis reveals that the Sichuan population forms a new monophyletic group (Bootstraps = 100). In the past ten thousand years, the population sizes of A. laboriosa in four different regions of China have been decreasing rapidly. Measures should be taken to protect them across the entire distribution range, especially the populations in Tibet and Sichuan, due to their relatively large genetic differences and low intra-population genetic diversity. Based on the significant difference analysis, the following four wing vein morphological features with extremely significant differences were identified: the width of the right forewing (FB), the cubital index a/b (Ci), the forewing vein angle (E9), and the forewing vein angle (K19). These findings are expected to offer a valuable reference for future A. laboriosa conservation endeavors, particularly in protecting populations with a high level of genetic differentiation.

Joint analysis of chromatin accessibility and gene expression in the same single cells reveals cancer-specific regulatory programs

Biological analyses conducted at the single-cell scale have revealed profound impacts of heterogeneity and plasticity of chromatin states and gene expression on physiology and cancer. Here, we developed Parallel-seq, a technology for simultaneously measuring chromatin accessibility and gene expression in the same single cells. By combining combinatorial cell indexing and droplet overloading, Parallel-seq generates high-quality data in an ultra-high-throughput fashion and at a cost two orders of magnitude lower than alternative technologies (10× Multiome and ISSAAC-seq). We applied Parallel-seq to 40 lung tumor and tumor-adjacent clinical samples and obtained over 200,000 high-quality joint scATAC-and-scRNA profiles. Leveraging this large dataset, we characterized copy-number variations (CNVs) and extrachromosomal circular DNA (eccDNA) heterogeneity in tumor cells, predicted hundreds of thousands of cell-type-specific regulatory events, and identified enhancer mutations affecting tumor progression. Our analyses highlight Parallel-seq's power in investigating epigenetic and genetic factors driving cancer development at the cell-type-specific level and its utility for revealing vulnerable therapeutic targets.

Parental Phasing Study Identified Lineage-Specific Variants Associated with Gene Expression and Epigenetic Modifications in European-Chinese Hybrid Pigs

Understanding how hybrids integrate lineage-specific regulatory variants at the haplotype level is crucial for elucidating the genetic basis of heterosis in livestock. In this study, we established three crossbred pig families derived from distant genetic lineages and systematically identified variants from different lineages, including single nucleotide polymorphisms (SNPs) and structural variations (SVs). At the phase level, we quantitatively analyzed gene expression, four histone modifications (H3K4me3, H3K27ac, H3K4me1, and H3K27me3), and the binding strength of transcription factor (CTCF) in backfat (BF) and longissimus dorsi (LD) muscle. By colocalization analysis of phased genetic variants with phased gene expression levels and with phased epigenetic modifications, we identified 18,670 expression quantitative trait loci (eQTL) (FDR < 0.05) and 8,652 epigenetic modification quantitative trait loci (epiQTL) (FDR < 0.05). The integration of eQTL and epiQTL allowed us to explore the potential regulatory mechanisms by which lineage-specific genetic variants simultaneously influence gene expression and epigenetic modifications. For example, we identified a Large White lineage-specific duplication (DUP) encompassing the KIT gene that was significantly associated with its promoter activity (FDR = 7.83 × 10-4) and expression levels (FDR = 9.03 × 10-4). Additionally, we found that a Duroc lineage-specific SNP located upstream of AMIGO2 was significantly associated with a Duroc-specific H3K27ac peak (FDR = 0.035) and also showed a significant association with AMIGO2 expression levels (FDR = 5.12 × 10-4). These findings underscore the importance of phased regulatory variants in shaping lineage-specific transcriptional programs and highlight how the haplotype-resolved integration of eQTL and epigenetic signals can reveal the mechanistic underpinnings of hybrid regulatory architecture. Our results offer insights for molecular marker development in precision pig breeding.

Reveal genomic insights into cotton domestication and improvement using gene level functional haplotype-based GWAS

Genome-wide association studies (GWAS) are widely used to detect associations between genetic variants and phenotypes. However, few studies have thoroughly analyzed genes, the fundamental and most crucial functional units. Here, we develop an innovative strategy to translate genomic variants into gene-level functional haplotypes (FHs), effectively reducing the interference from complex genome structure and linkage disequilibrium (LD) present in the conventional genetic mapping framework. Using refined mixed linear models, gene-level FH is regressed with 20 cotton agronomic traits across 245 sets of phenotypic values in 3,724 accessions, directly identifying 532 quantitative trait genes (QTGs) with significant breeding potential. The biological function of a superior fiber quality QTG encoding ferulic acid 5-hydroxylase 1 is experimentally validated. Thereafter, we systematically analyze the genetic basis of cotton domestication and improvement at the gene level. This report provides genomic insight into the genetic dissection and efficient mapping of functional genes in plants.

Mitogenome of Endemic Species of Flying Squirrel, Trogopterus xanthipes (Rodentia, Mammalia) and Phylogeny of the Sciuridae

Trogopterus xanthipes (Sciuridae, Rodentia) is a medium-sized flying squirrel species in the monotypic genus Trogopterus, and is endemic to China. It is distinguishable from other squirrels by the long black hairs on the inner and outer sides at the base of the ears and numerous ridges on the crowns of the upper and lower cheek teeth. Mitogenomes have been widely used in phylogenetic studies. We described T. xanthipes morphological features and successfully sequenced its mitogenome for the first time. The T. xanthipes mitogenome was conserved in number and order of genes. We analyzed codon usage patterns, evolutionary mutation rates, K2P distance, and genetic diversity of protein-coding genes. We reconstructed the phylogeny of Sciuridae (94 species and 21 genera in 4 subfamilies). All phylogenetic trees shared the same topologies and consistently supported the monophyly of Sciuridae, and the supported subfamilies relationship as follows: ((Xerinae + Callosciurinae) + Sciurinae) + Ratufinae. The relationship within the Sciurinae clade was ((Glaucomys + Hylopetes) + ((Trogopterus+Pteromys) + Petaurista) + Sciurus). The relationship within the Callosciurinae clade was Exilisciurus + ((Tamiops + Dremomys) + ((Lariscus+Sundasciurus) + Callosciurus)). The relationship within the Xerinae clade was Sciurotamias + (Tamias + (Callospermophilus + (Marmota + (Spermophilus + (Urocitellus + (Ictidomys + Cynomys)))))). The phylogenetic position among different subfamilies of Sciuridae was consistently recovered with high support across different datasets (PCGRNA and PCG12RNA) and supported the monophyletic lineage of each genus of Sciuridae. Trogopterus xanthipes was sister species to Pteromys volans. Species within the genus formed different minor clades, suggesting relatively high interspecific divergences. The tribe Pteromyini was sister taxon of the tribe Sciurini, which was not supported by the traditional division of Sciuridae into subfamilies Pteromyinae and Sciurinae. Hence, our data supported a division of the Sciuridae into five subfamilies.

Germline mutagenicity of molnupiravir and its active form, β-d-N4-hydroxycytidine, in Caenorhabditis elegans evaluated using whole-genome sequencing

Molnupiravir is a medication used to treat COVID-19 by introducing errors into the SARS-CoV-2 virus's genetic code, thereby preventing its replication. Previous studies, both in vitro and in vivo, have yielded conflicting results regarding its mutagenic potential. While most genotoxicity and mutagenicity tests for molnupiravir and its active form, β-d-N4-hydroxycytidine (NHC), were negative, a few in vitro tests showed positive results. Consequently, further investigation is necessary to evaluate various mutagenic endpoints of molnupiravir. In this study, acute toxicity was assessed by measuring the locomotive activity of Caenorhabditis elegans using a WMicroTracker to determine an appropriate dose range for the germline mutagenicity study. The C. elegans worms were treated with different concentrations of molnupiravir and NHC, along with vehicle controls and ethyl methanesulfonate (EMS) as a positive control. To assess germline mutagenicity, P0 worms from a single clone were exposed to selected concentrations of molnupiravir and NHC, as well as vehicle and positive controls, for 4h. Molnupiravir and NHC treatments had no significant effect on the locomotion of C. elegans worms after 1-, 2-, 3-, and 4-h exposures, compared to the vehicle control group. In contrast, EMS significantly reduced the worms' locomotive activity. Subsequent whole-genome sequencing of the F1 progeny from the treated P0 worms revealed that neither molnupiravir nor NHC increased the germline mutation frequency or altered mutation types, compared to the vehicle control. In contrast, EMS treatment significantly increased mutation frequency over the vehicle control, with a specific EMS mutational signature observed. These results suggest that molnupiravir and NHC are not mutagenic in C. elegans germ cells, aligning with previous findings that demonstrate the low mutagenicity of molnupiravir in clinical settings. Additionally, these findings highlight the utility of C. elegans as an alternative animal model for accelerating toxicity assessments and reducing the use of experimental animals.

A specific form of cPRC1 containing CBX4 is co-opted to mediate oncogenic gene repression in diffuse midline glioma

Diffuse midline glioma (DMG) is a fatal childhood brain tumor characterized primarily by mutant histone H3 (H3K27M). H3K27M causes a global reduction in Polycomb repressive complex 2 (PRC2)-mediated H3K27 trimethylation (H3K27me3). Paradoxically, PRC2 is essential in DMG cells, although the downstream molecular mechanisms are poorly understood. Here, we have discovered a specific form of canonical PRC1 (cPRC1) containing CBX4 and PCGF4 that drives oncogenic gene repression downstream of H3K27me3 in DMG cells. Via a novel functional region, CBX4 preferentially associates with PCGF4-containing cPRC1. The characteristic H3K27me3 landscape in DMG rewires the distribution of cPRC1 complexes, with CBX4/PCGF4-cPRC1 accumulating at H3K27me3-enriched CpG islands. Despite comprising <5% of cPRC1 in DMG cells, the unique repressive functions of CBX4/PCGF4-cPRC1 are essential for DMG growth. Our findings link the altered distribution of H3K27me3 to imbalanced cPRC1 function, which drives oncogenic gene repression in DMG, highlighting potential therapeutic opportunities for this incurable childhood brain cancer.

Genome-wide identification and characterization of lipoxygenases gene family in Luffa aegyptiaca revealed downregulation of LOX genes under heat stress

Lipoxygenases (LOXs) are key enzymes in plant lipid metabolism and stress responses, yet their genomic organization and functional dynamics in Luffa aegyptiaca-a species of culinary, medicinal, and ornamental importance-remain unexplored. Here, we present the first genome-wide identification and characterization of the LOX gene family in L. aegyptiaca, revealing 29 LOX genes, including 14 members of 13S-lipoxygenases (13-LOX) and 15 members of 9S-lipoxygenases (9-LOX), respectively. Notably, tandem duplication events shaped the expansion of LOX genes, with 24 genes clustered in two loci, suggesting functional diversification to enhance environmental adaptability. Phylogenetic analysis demonstrated evolutionary conservation of LOX genes across Cucurbitaceae species, while collinearity analysis highlighted conserved genomic organization. Promoter cis-element profiling identified stress- and hormone-responsive motifs, implicating LOX genes in developmental and stress regulatory networks. Tissue-specific expression patterns revealed 18 LOX genes predominantly expressed in tendril, fruit, root, and male flower, linking them to organ-specific physiological roles. Crucially, under heat stress, 9 out of 11 expressed LOX genes were significantly downregulated, indicating their potential role in thermal stress adaptation through metabolic reconfiguration. This study provides foundational insights into the LOX family's contribution to L. aegyptiaca's resilience and offers genetic targets for breeding strategies to improve stress tolerance in cucurbit crops.

Tracking the genome-wide occupancy of Arabidopsis LEAFY COTYLEDON1 in endosperm development

Endosperm development is crucial for embryo growth and seed maturation. LEAFY COTYLEDON1 (LEC1), expressed in both endosperm and embryo, serves as a key regulator of seed development, orchestrating processes such as embryogenesis and seed maturation. LEC1 expression in the endosperm is detectable within a day after fertilization, yet its specific regulatory networks and developmental functions in this tissue remain unclear. To address this, we employed a modified INTACT system to isolate endosperm nuclei and performed ChIP-seq to map the genome-wide binding profile of LEC1 in developing endosperm. Integrating ChIP-seq with transcriptomic analyses, we uncover a critical role for LEC1 in regulating diverse biological pathways. Differential gene expression analysis in the endosperms of lec1 mutant and wild type shows substantial changes, particularly in genes involved in secondary cell wall biogenesis, photosynthesis, and lipid metabolism. Notably, LEC1's regulatory networks in the endosperm shift significantly after cellularization, with distinct genes being activated in the cellular and degeneration stages. The absence of LEC1 causes significant alterations in endosperm metabolism, particularly affecting storage lipid fatty acid composition. These findings provide insights into the essential role of LEC1 in endosperm development and its broader impact on seed formation.

Deciphering enhancers of hearing loss genes for efficient and targeted gene therapy of hereditary deafness

Hereditary hearing loss accounts for about 60% of congenital deafness. Although adeno-associated virus (AAV)-mediated gene therapy shows substantial potential for treating genetic hearing impairments, there remain significant concerns regarding the specificity and safety of AAV vectors. The sophisticated nature of the cochlea further complicates the challenge of precisely targeting gene delivery. Here, we introduced an AAV-reporter-based in vivo transcriptional enhancer reconstruction (ARBITER) workflow, enabling efficient and reliable dissection of enhancers. With ARBITER, we successfully demonstrated that the conserved non-coding elements (CNEs) within the gene locus collaboratively regulate the expression of Slc26a5, which was further validated using knockout mouse models. We also assessed the potential of identified enhancers to treat hereditary hearing loss by conducting gene therapy in Slc26a5 mutant mice. Based on the original Slc26a5 enhancer with limited efficiency, we engineered a highly efficient and outer hair cell (OHC)-specific enhancer, B8, which successfully restored hearing of Slc26a5 knockout mice.

CREBBP inactivation sensitizes B cell acute lymphoblastic leukemia to ferroptotic cell death upon BCL2 inhibition

B-cell acute lymphoblastic leukemia (B-ALL) is a leading cause of death in childhood and outcomes in adults remain dismal. There is therefore an urgent clinical need for therapies that target the highest risk cases. Mutations in the histone acetyltransferase CREBBP confer high-risk and increased chemoresistance in ALL. Performing a targeted drug-screen in isogenic human cell lines, we identify a number of small molecules that specifically target CREBBP-mutated B-ALL, the most potent being the BCL2-inhibitor Venetoclax. Of note, this acts through a non-canonical mechanism resulting in ferroptotic rather than apoptotic cell death. CREBBP-mutated cell lines show differences in cell-cycle, metabolism, lipid composition and response to oxidative stress, predisposing them to ferroptosis, which are further dysregulated upon acquisition of Venetoclax resistance. Lastly, small-molecule inhibition of CREBBP pharmacocopies CREBBP-mutation, sensitizing B-ALL cells, regardless of genotype, to Venetoclax-induced ferroptosis in-vitro and in-vivo, providing a promising drug combination for broader clinical translation in B-ALL.

Prognostic impact of biomarkers in PMBCL: rationale for early integration of immune checkpoint inhibitors

Aim

This research aims to guide future strategies for personalized treatment of primary mediastinal large B-cell lymphoma (PMBCL), particularly to identify high-risk patients who may benefit from incorporating immune checkpoint inhibitors (ICIs) in the first-line setting.

Methods

A retrospective, single-center study included 254 newly diagnosed PMBCL patients treated with rituximab, dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin (R-DA-EPOCH), rituximab, modified protocol NHL-BFM-90 (RmNHL-BFM-90), or R-DA-EPOCH combined with nivolumab. Clinical parameters, immunohistochemical markers [programmed death ligand-1 (PD-L1), programmed death-1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), human leucocyte antigen (HLA)-DR, Ki-67, multiple myeloma oncogene 1 (MUM1)], molecular markers (mutations in tumor protein p53 (TP53), CD58, beta-2-microglobulin (B2M), and exportin 1 (XPO1) genes; short tandem repeats at 6p21.3 [major histocompatibility complex (MHC) class I/II], 9p24.1 (PD-L1/PD-L2), 16p13.13 [class II, MHC, transactivator gene (CIITA)]), and cytogenetic profiles [myelocytomatosis oncogene (MYC)/8q24, B-cell lymphoma 2 (BCL2)/18q21, BCL6/3q27, del17p13, and karyotype abnormalities] were analyzed.

Results

The addition of nivolumab to R-DA-EPOCH as a first-line regimen significantly improved event-free survival (EFS; P = 0.018). This study identified that adverse prognostic factors for PMBCL include allelic imbalance at specific loci 6p21.3 (MHC class I/II), 9p24.1 (PD-L1/PD-L2), and 16p13.13 (CIITA). Incorporating nivolumab into the R-DA-EPOCH regimen as a first-line therapy has shown potential in reducing adverse prognostic factors.

Conclusions

These findings suggest that high-risk patients may benefit significantly from the early incorporation of ICIs into their treatment plans.

ACSS2 mediates an epigenetic pathway to regulate β-cell adaptation during gestation in mice

Maternal pancreatic β-cells undergo adaptive changes to meet the metabolic demands of pregnancy, and disruptions in this adaptation can lead to gestational diabetes mellitus. However, the mechanisms governing this adaptation remain largely unexplored. Using single-cell transcriptome combined with genetic analyses, we identified a precise process of β-cell adaptation in mice, characterized by progressive metabolic stress-related β-cell dysfunction, increased acetyl-CoA biosynthesis, and gene element-specific histone acetylation. STAT3 recruits p300 to promote histone acetylation of pregnancy-associated genes, a process enhanced by Acetyl-CoA Synthetase 2 (ACSS2). High-fat feeding induces hyperacetylation of chromatin regions specifically opened during pregnancy, leading to the overexpression of genes that impair β-cell function. However, these impairments can be rescued by β-cell-specific deletion of Acss2. Notably, ACSS2 is functionally implicated in the early establishment of β-cell adaptation in HFD-fed mice but does not appear to play a role in standard diet-fed mice until after the initiation of adaptation. Our study uncovers a finely regulated β-cell adaptation process at the single-cell level during pregnancy and identifies a specific epigenetic pathway that governs this process. These findings provide insights into β-cell plasticity and potential therapeutic strategies for gestational diabetes mellitus.

Deciphering the First Mitochondrial Genome of the Liolophura Pilsbry, 1893 Genus: An Extensive Phylogenetic Study Within the Chitonidae Family

Background: The Polyplacophora class, which includes all chitons, is distinguished by its unique eight-piece interlocking armor, showcasing a vast diversity in marine environments. However, the detailed evolutionary relationships within the Chitonidae family remain largely unknown. The mitochondrial genome is essential for understanding these relationships, but there has been a significant lack of such genomic information, especially for the Liolophura genus. Methods: We generated the first mitogenome of Liolophura japonica by assembling Illumina reads with GetOrganelle, polishing with Pilon, annotating genes with MitoZ and MITOS2, and inferring phylogeny from 13 concatenated protein-coding genes (PCGs) using MAFFT and IQ-TREE. Results: The mitogenome is 15,209 base pairs long and includes 13 protein-coding genes, 22 transfer RNAs, and 2 ribosomal RNAs. The mitogenome exhibited a slight AT bias common in Chitonidae and showcased structural uniqueness with no control region found. Notably, all protein-coding genes demonstrated evidence of purifying selection, with Ka/Ks ratios below 1, highlighting evolutionary conservation. Phylogenetic analysis reveals a close relationship between L. japonica, Acanthopleura loochooana Broderip & Sowerby 1829, and Acanthopleura vaillantii Rochebrune, 1882, potentially warranting future taxonomic re-evaluation. This research emphasizes the crucial role of mitochondrial genomes in mollusk phylogeny and sets the stage for advanced genetic studies within this group. Conclusions: The significance of this study lies in its contribution to understanding the mitochondrial genome of L. japonica, a key species within the Polyplacophora class. By analyzing its mitogenome, we aim to enhance our understanding of evolutionary processes in chitons and other mollusks.

Haplotype-resolved chromosome-level genome sequence of Elsholtzia splendens (Nakai ex F.Maek.)

Elsholtzia splendens, a perennial herb native to East Asia, is valued for its ornamental and medicinal uses, particularly in treating inflammatory and febrile conditions. Recent studies have highlighted its antibacterial, anti-inflammatory, antidepressant, antithrombotic, and lipid-lowering properties of its compounds. Additionally, E. splendens shows potential for phytoremediation owing to its ability to hyperaccumulate copper (Cu), lead (Pb), zinc (Zn), and cadmium (Cd). However, its role in remediation conflicts with its medicinal use because of the risk of heavy metal accumulation. Genome sequencing will be key to boosting beneficial compound production and reducing heavy metal risks. In this study, we generated a high-resolution, haplotype-resolved, chromosome-scale genome sequence of E. splendens using PacBio Revio long-read, Illumina short-read, and Hi-C sequencing technologies. The haplotype genome assemblies, spanned 275.4 and 265.0 Mbp with a scaffold N50 of 33.9 and 33.8 Mbp for haplotype 1 and 2, respectively. This assembly provides valuable insights into medicinal compound biosynthesis and supports genetic conservation efforts, facilitating future genetic and biotechnological applications of E. splendens for medicinal and ecological uses.

Genomic map of the functionally extinct northern white rhinoceros (Ceratotherium simum cottoni)

The northern white rhinoceros (NWR; Ceratotherium simum cottoni) is functionally extinct, with only two nonreproductive females alive. Efforts to rescue the NWR from its inevitable demise have inspired the exploration of unconventional conservation methods, including the development of induced pluripotent stem cells (iPSCs) for the in vitro generation of artificial gametes. The integrity of iPSC genomes is critical for in vitro gametogenesis to be used for assisted reproductive technologies using NWR iPSCs. We generated a chromosome-level NWR reference genome that meets or exceeds the metrics proposed by the Vertebrate Genome Project, using complementary sequencing and mapping methods. The genome represents 40 autosomes, an X and a partially resolved Y chromosome, and the mitochondrial genome. Using comparative FISH mapping, we confirmed a general gene order conservation between the NWR and horse genomes. We aligned the NWR genome with that of the southern white rhinoceros (SWR; Ceratotherium simum simum), a population that has been physically separated from the NWR for tens of thousands of years, and we found that the two subspecies are very similar on the chromosome level. Comparing long-read data from NWR iPSC lines and the fibroblast cultures used for reprogramming, we identified copy number variations that were likely to have been introduced during in vitro iPSC expansion. The NWR reference genome allows for efficient, rapid, and accurate assessment of the genomic integrity of iPSC lines to direct their differentiation. This will assist in strategies to rescue the NWR through extraordinary measures like cloning and the generation of embryos from iPSC-derived gametes.

Urbanization and genetic homogenization in the medieval Low Countries revealed through a ten-century paleogenomic study of the city of Sint-Truiden

BACKGROUND

Processes shaping the formation of the present-day population structure in highly urbanized Northern Europe are still poorly understood. Gaps remain in our understanding of when and how currently observable regional differences emerged and what impact city growth, migration, and disease pandemics during and after the Middle Ages had on these processes.

RESULTS

We perform low-coverage sequencing of the genomes of 338 individuals spanning the eighth to the eighteenth centuries in the city of Sint-Truiden in Flanders, in the northern part of Belgium. The early/high medieval Sint-Truiden population was more heterogeneous, having received migrants from Scotland or Ireland, and displayed less genetic relatedness than observed today between individuals in present-day Flanders. We find differences in gene variants associated with high vitamin D blood levels between individuals with Gaulish or Germanic ancestry. Although we find evidence of a Yersinia pestis infection in 5 of the 58 late medieval burials, we were unable to detect a major population-scale impact of the second plague pandemic on genetic diversity or on the elevated differentiation of immunity genes.

CONCLUSIONS

This study reveals that the genetic homogenization process in a medieval city population in the Low Countries was protracted for centuries. Over time, the Sint-Truiden population became more similar to the current population of the surrounding Limburg province, likely as a result of reduced long-distance migration after the high medieval period, and the continuous process of local admixture of Germanic and Gaulish ancestries which formed the genetic cline observable today in the Low Countries.

Identification of Two Novel Recombinant Types of Potato Virus Y from Solanum tuberosum Plants in the Southern Region of Russia

Potato virus Y (PVY; genus Potyvirus, family Potyviridae) is one of the most devastating and economically important potato pathogens. Members of the Potyviridae family demonstrate high recombination rates. In nature, five major parental variants of PVY were identified with at least 35 recombinants. In this study, we report two novel PVY recombinants discovered in the sprouts of potato tubers produced in field conditions in the Astrakhan region of Russia in 2021 using high-throughput sequencing and de novo genome assembly. These recombinants, which were named Ast-A-I and Ast-A-II, have previously unknown arrangements of genome sections derived from PVYO and PVYN, with a novel recombination junction at position 7,850 nt of the PVY genome in the middle part of the RNA-dependent RNA polymerase (NIb) gene, with PVYO type sequence at the 5' end relative to this junction and PVYN type at the 3' end. Other recombinant junctions in the novel PVY variants were previously found in PVYNTNa and PVYNTNb. This includes those at positions 2,390 and 9,200 (PVYN at the 5' end and PVYIS° at the 3' end), which were present in both novel recombinants, and at position 500 (PVYO at the 5' end and PVYN at the 3' end), which present in Ast-A-II. The presence of PVY variants with a novel recombinant point is verified by Sanger sequencing. Phylogenetic analysis of genomic RNA showed that the sequences of these recombinants form a separate branch that do not cluster with previously described PVY strains.

Draft genome sequence of Solidesulfovibrio sp. strain C21 isolated from Laguna Grande (Lagunas de Villafranca), Spain

Here, we report the draft genome sequence of a strain of Solidesulfovibrio isolated from hypersaline sediment samples collected from Laguna Grande (Lagunas de Villafranca), La Mancha Region, Spain. This genome sequence enables further investigation into the genetic and metabolic diversity of sulfate reducers in extreme, hypersaline environments.

RNA sequencing analysis of viromes of Aedes albopictus and Aedes vexans collected from NEON sites

Climate change is significantly impacting the geographic range of many animal species and their associated microorganisms, hence influencing emergence of vector-borne diseases. Mosquito-borne viruses represent a potential major reservoir of human pathogens, highlighting the need for improved understanding of ecological factors associated with variation in the mosquito viral community (virome). Here, a subtractive hybridization method coupled with RNAseq of individual mosquito specimens was used to profile RNA viromes of individual co-occurring Aedes albopictus and Aedes vexans mosquitoes across a 2,000 km spatial scale. Samples were collected and archived by the National Ecological Observatory Network (NEON) from four ecologically variable sites in the Southeastern United States between 2018 and 2019. Results of multivariate analysis suggest that mosquito species are an important factor in RNA viral community composition. Significantly higher viral diversity was detected in A. albopictus compared to A.vexans. However, season, year, and site of sample collection did not show strong association with virome profiles, supporting the hypothesis that factors unique to the mosquito host species (e.g., larval habitat or vector competence) influence the structure of mosquito viromes.

Clinical Bioinformatician Body of Knowledge-Bioinformatics and Software Core: A Report of the Association for Molecular Pathology

With the evolution of next-generation sequencing-based testing in molecular diagnostics laboratories, the clinical role of bioinformaticians has also evolved. The Association for Molecular Pathology's Clinical Bioinformatician Body of Knowledge aims to define the various roles the clinical bioinformatician operates individually or within a clinical bioinformatics team, along with proficiencies and skill sets that may be required or desirable across these roles. One of the most common professional responsibilities of a clinical bioinformatician is to implement bioinformatics pipelines, either vendor supplied or custom built for the assays in the molecular diagnostics laboratory, along with analysis and quality control of clinical genomics data. This second article in the series describes the various stages in the life cycle of a clinical bioinformatics pipeline and the considerations, areas of expertise, and skill sets required in each stage. This information may help laboratory professionals to better work with clinical bioinformaticians and laboratory directors to hire the appropriate expertise based on the specific needs of the laboratory.

Human endogenous retroviruses (HERVs) associated with glioblastoma risk and prognosis

Emerging evidence suggests expression from human endogenous retrovirus (HERV) loci likely contributes to, or is a biomarker of, glioblastoma multiforme (GBM) disease progression. However, the relationship between HERV expression and GBM malignant phenotype is unclear. Applying several in silico analyses based on data from The Cancer Genome Atlas (TCGA), we derived a locus-specific HERV transcriptome for glioma that revealed 211 HERVs significantly dysregulated in the comparisons of GBM vs. normal brain (NB), GBM vs. low-grade glioma (LGG), and LGG vs. NB. Our analysis supported development of a unique HERV scoring algorithm that segregated GBM, LGG, and NB. Interestingly, lower HERV scores showed correlation with lower survival in GBM. However, HERV scores were less robust in predicting LGG survival or LGG progression to GBM. Functional prediction analysis linked the 211 HERV loci with 18 voltage-gated potassium channel genes. The functional link between dysregulated HERVs and specific potassium channel genes may contribute to better understanding of GBM pathogenesis, disease progression, and possibly drug resistance.

Physiological roles of an Acinetobacter-specific σ factor

The Gram-negative pathogen Acinetobacter baumannii is considered an "urgent threat" to human health due to its propensity to become antibiotic resistant. Understanding the distinct regulatory paradigms used by A. baumannii to mitigate cellular stresses may uncover new therapeutic targets. Many γ-proteobacteria use the extracytoplasmic function (ECF) σ factor, RpoE, to invoke envelope homeostasis networks in response to stress. Acinetobacter species contain the poorly characterized ECF "SigAb"; however, it is unclear if SigAb has the same physiological role as RpoE. Here, we show that SigAb is a metal stress-responsive ECF that appears unique to Acinetobacter species and distinct from RpoE-like ECFs. We combine promoter mutagenesis, motif scanning, and chromatin immunoprecipitation-sequencing (ChIP-seq) to define the direct SigAb regulon, which consists of genes encoding SigAb itself, the stringent response mediator, RelA, and the uncharacterized small RNA, "SabS." However, RNA-seq of strains overexpressing SigAb revealed a large, indirect regulon containing hundreds of genes. Metal resistance genes are key elements of the indirect regulon, as CRISPRi knockdown of sigAb or sabS resulted in increased copper sensitivity and excess copper-induced SigAb-dependent transcription. Furthermore, we found that two uncharacterized genes in the sigAb operon, "aabA" and "aabB," have anti-SigAb activity. Finally, employing a targeted Tn-seq approach that uses CRISPR-associated transposons, we show that sigAb, aabA, and aabB are important for fitness even during optimal growth conditions. Our work reveals new physiological roles for SigAb and SabS, provides a novel approach for assessing gene fitness, and highlights the distinct regulatory architecture of A. baumannii.

IMPORTANCE

Acinetobacter baumannii is a hospital-acquired pathogen, and many strains are resistant to multiple antibiotics. Understanding how A. baumannii senses and responds to stress may uncover novel routes to treat infections. Here, we examine how the Acinetobacter-specific transcription factor, SigAb, mitigates stress. We find that SigAb directly regulates only a small number of genes, but indirectly controls hundreds of genes that have substantial impacts on cell physiology. We show that SigAb is required for maximal growth, even during optimal conditions, and is acutely required during growth in the presence of elevated copper. Given that copper toxicity plays roles in pathogenesis and on copper-containing surfaces in hospitals, we speculate that SigAb function may be important in clinically relevant contexts.

Complete Mitochondrial Genome Characterization and Phylogenomics of the Stingless Bee, Heterotrigona itama (Apidae: Meliponini)

With increasing demand for stingless bee honey, meliponiculture has gained widespread attention. Heterotrigona itama is one of the most economically important species. However, excessive exploitation for commercial purposes has led to population declines, and the species is now considered vulnerable in Thailand. Despite its ecological and economic significance, genomic and taxonomic information on H. itama remains limited. In this study, we sequenced and characterized the complete mitochondrial genome (mitogenome) of H. itama to explore its genome structure and phylogenetic position. The circular mitogenome is 15,318 bp in length and consists of 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, and 2 ribosomal RNA (rRNA) genes. The genome exhibits a strong A+T bias (75.41%), which affects codon usage and amino acid composition. Isoleucine, methionine, and phenylalanine were the most commonly encoded amino acids. Gene arrangement was highly conserved and closely resembled that of Tetragonula species. Phylogenetic analyses confirmed that H. itama clusters with other stingless bees and is more closely related to bumblebees than to honeybees. Several gene rearrangements suggest a high degree of mitogenomic plasticity. This study provides essential genomic resources for future studies in systematics, phylogenetics, population genetics, and conservation of stingless bees in the Meliponini tribe.

Autophagy-Related Proteins (ATGs) Are Differentially Required for Development and Virulence of Sclerotinia sclerotiorum

Sclerotinia sclerotiorum is a devastating fungal pathogen that can colonize numerous crops. Despite its economic importance, the regulation of its development and pathogenicity remains poorly understood. From a forward genetic screen in S. sclerotiorum, six UV mutants were identified with loss-of-function mutations in SsATG1, SsATG2, SsATG4, SsATG5, SsATG9, and SsATG26. Functional validation through gene knockouts revealed that each ATG is essential for sclerotia formation, although the morphology of appressoria was not significantly altered in the mutants. Different levels of virulence attenuation were observed among these mutants. Autophagy, monitored using GFP-ATG8, showed dynamic activities during sclerotia development. These findings suggest that macroautophagy and pexophagy contribute to sclerotia maturation and virulence processes. Future work will reveal how autophagy controls target organelle or protein turnover to regulate these processes.

Wnt/β-catenin activation by mutually exclusive FBXW11 and CTNNB1 hotspot mutations drives salivary basal cell adenoma

Basal cell adenoma (BCA) and basal cell adenocarcinoma (BCAC) of the salivary gland are rare tumours that can be difficult to distinguish from each other and other salivary gland tumour subtypes. Using next-generation sequencing, we identify a recurrent FBXW11 missense mutation (p.F517S) in BCA that is mutually exclusive with the previously reported CTNNB1 p.I35T gain-of-function (GoF) mutation with these mutations collectively accounting for 94% of BCAs. In vitro, mutant FBXW11 is characterised by defective binding to β-catenin and higher protein levels within the nucleus. This is consistent with the increased nuclear expression of β-catenin and activation of the Wnt/β-catenin pathway. The genomic profiles of BCAC are distinct from BCA, with hotspot DICER1 and HRAS mutations and putative driver mutations affecting PI3K/AKT and NF-κB signalling pathway genes. These findings have important implications for the diagnosis and treatment of BCA and BCAC, which, despite histopathologic overlap, may be unrelated entities.

High-resolution sequencing reveals that the Paf1 complex may be a conserved transcription elongation factor for eukaryotic RNA polymerase I

In eukaryotes, at least three Pols (I, II, and III) are responsible for synthesizing unique RNA products. Many trans-acting factors affect the efficiency of transcription by the three Pols. Some of these factors influence more than one of the nuclear Pols. One such factor is polymerase-associated factor 1 complex (Paf1C). Paf1C, composed of five subunits in Saccharomyces cerevisiae (yeast), has been shown to promote transcription by Pols I and II and is conserved across eukaryotes. Although several studies have demonstrated that Paf1C associates with Pol I machinery, its roles in ribosomal RNA synthesis are not well-defined. In this study, we used native elongating transcript sequencing (NET-seq), to investigate the effect of the loss of two of the five Paf1C subunits (Paf1 and Cdc73) on Pol I occupancy at single-nucleotide resolution in yeast. We found that in both paf1Δ and cdc73Δ mutants, there was a significant reduction in Pol I occupancy at the 5' end of the DNA template as compared to WT yeast, accompanied by other occupancy pattern changes throughout the gene. To complement these results, we also analyzed a PRO-seq dataset that was generated with DLD1 mammalian cells. Interestingly, we found that when Paf1C was knocked-down, there was also a reduction in the occupancy of Pol I at the 5' end of the gene, consistent with our NET-seq analysis. Overall, our results support the conclusion that Paf1C is an important transcription elongation factor for Pol I and may play a conserved role across species.

Genetic control of the leaf ionome in pearl millet and correlation with root and agromorphological traits

Pearl millet (Pennisetum glaucum) thrives in arid and nutrient-poor environments, establishing its role as a crucial cereal crop for food security in sub-Saharan Africa. Despite its remarkable adaptability, its yields remain below genetic potential, primarily due to limited water and nutrient availability. In this study, we conducted ionomic profiling and genome-wide association studies (GWAS) in field conditions across two growing seasons to unravel the genetic basis of nutrient acquisition in pearl millet. Soil ion content analyses revealed significant differences in nutrient distribution between field sites, while certain ions, such as phosphorus (P) and zinc (Zn), consistently displayed stratified accumulation patterns across years, suggesting stable depth-dependent trends. Evaluation of a genetically diverse panel of inbred lines revealed substantial variation in leaf ion concentrations, with high heritability estimates. Correlations between leaf ion content and root anatomical or agromorphological traits highlighted the intricate interplay between genetic and environmental factors shaping leaf ion accumulation. These analyses also uncovered potential trade-offs in nutrient acquisition strategies. GWAS identified genomic regions associated with leaf ion concentrations, and the integration of genetic and gene expression data facilitated the identification of candidate genes implicated in ion transport and homeostasis. Our findings provide valuable insights into the genetic regulation of nutrient acquisition in pearl millet, offering potential targets for breeding nutrient-efficient and climate-resilient varieties. This study underscores the importance of integrating genetic, physiological, and root architectural traits to enhance agricultural productivity and sustainability in resource-constrained environments.

CHAS infers cell type-specific signatures in bulk brain histone acetylation studies of neurological and psychiatric disorders

Epigenomic profiling of the brain has largely been done on bulk tissues, limiting our understanding of cell type-specific epigenetic changes in disease states. Here, we introduce cell type-specific histone acetylation score (CHAS), a computational tool for inferring cell type-specific signatures in bulk brain H3K27ac profiles. We applied CHAS to >300 H3K27ac chromatin immunoprecipitation sequencing samples from studies of Alzheimer's disease, Parkinson's disease, autism spectrum disorder, schizophrenia, and bipolar disorder in bulk postmortem brain tissue. In addition to recapitulating known disease-associated shifts in cellular proportions, we identified cell type-specific biological insights into brain-disorder-associated regulatory variation. In most cases, genetic risk and epigenetic dysregulation targeted different cell types, suggesting independent mechanisms. For instance, genetic risk of Alzheimer's disease was exclusively enriched within microglia, while epigenetic dysregulation predominantly fell within oligodendrocyte-specific H3K27ac regions. In addition, reanalysis of the original datasets using CHAS enabled identification of biological pathways associated with each neurological and psychiatric disorder at cellular resolution.

Transcriptional and epigenetic rewiring by the NUP98::KDM5A fusion oncoprotein directly activates CDK12

Nucleoporin 98 (NUP98) fusion oncoproteins are strong drivers of pediatric acute myeloid leukemia (AML) with poor prognosis. Here we show that NUP98 fusion-expressing AML harbors an epigenetic signature that is characterized by increased accessibility of hematopoietic stem cell genes and enrichment of activating histone marks. We employ an AML model for ligand-induced degradation of the NUP98::KDM5A fusion oncoprotein to identify epigenetic programs and transcriptional targets that are directly regulated by NUP98::KDM5A through CUT&Tag and nascent RNA-seq. Orthogonal genome-wide CRISPR/Cas9 screening identifies 12 direct NUP98::KDM5A target genes, which are essential for AML cell growth. Among these, we validate cyclin-dependent kinase 12 (CDK12) as a druggable vulnerability in NUP98::KDM5A-expressing AML. In line with its role in the transcription of DNA damage repair genes, small-molecule-mediated CDK12 inactivation causes increased DNA damage, leading to AML cell death. Altogether, we show that NUP98::KDM5A directly regulates a core set of essential target genes and reveal CDK12 as an actionable vulnerability in AML with oncogenic NUP98 fusions.

Dynamic deployment of H2A.Z positive nucleosome mediated transcriptomic plasticity within vascular smooth muscle cell

BACKGROUND

To maintain homeostasis in the mature human body, certain differentiated cells adopted high plasticity to refine their cellular functions. However, mechanisms that supported cellular plasticity still remained elusive. Here, through comprehensive transcriptomic and epigenetic studies of highly plastic vascular smooth muscle cells (SMCs), we aimed to decipher the chromatin basis that could mediate cellular plasticity.

RESULTS

In vascular smooth muscle cells, actively transcribed and highly adjustable genes tended to be associated with a continuously accessible region downstream of transcription start site (CAR-downTSS). This CAR-downTSS was located beyond the classic RNA polymerase II paused region, accessible at mono-nucleosome level and incorporated with histone variant H2A.Z. Depletion of H2A.Z reduced active histone modifications within CAR-downTSS, impaired RNA polymerase II transpassing when cells were stimulated, and consequently inhibited the ability of CAR-downTSS-associated genes to adjust their expression. Further in vitro and in vivo studies verified that this CAR-downTSS could be dynamically re-deployed onto different genes in vascular SMCs, whereas it was deployed in smaller quantities and remained quantitatively stable on genome within the quiescent cardiomyocytes.

CONCLUSIONS

Vascular SMCs dynamically deployed H2A.Z-positive nucleosomes extending continuously downstream transcription start sites on different genes to support their transcriptional adjustability, which served as an important mechanism mediating cellular plasticity.

Nanopore RNA direct sequencing identifies that m6A modification is essential for sorbitol-controlled resistance to Alternaria alternata in apple

Sorbitol, a main photosynthate and transport carbohydrate in all tree fruit species in Rosaceae, acts as a signal controlling resistance against Alternaria (A.) alternata in apple by altering the expression of the MdNLR16 resistance gene via the MdWRKY79 transcription factor. However, it is not known if N6-methyladenosine (m6A) methylation of the mRNAs of these genes participates in the process. Here, we found that decreased sorbitol synthesis in apple leaves leads to a transcriptome-wide reduction in the m6A modification, with fewer transcripts containing two or more methylation sites. We identified two methyltransferases, MdVIR1 and MdVIR2, that respond to sorbitol and A. alternata inoculation and positively control resistance to A. alternata. MdVIR1 and MdVIR2 act on MdWRKY79 and MdNLR16 mRNAs, and the resulting m6A modification stabilizes their mRNAs and improves translation efficiency. These data identify that m6A modification through MdVIR1 and MdVIR2 methyltransferases is essential for sorbitol-controlled resistance to A. alternata.

Deciphering the role of histone modifications in memory and exhausted CD8 T cells

Exhausted CD8 T cells (TEX) arising during chronic infections and cancer have reduced functional capacity and limited fate flexibility that prevents optimal disease control and response to immunotherapies. Compared to memory (TMEM) cells, TEX have a unique open chromatin landscape underlying a distinct gene expression program. How TEX transcriptional and epigenetic landscapes are regulated through histone post-translational modifications (hPTMs) remains unclear. Here, we profiled key activating (H3K27ac and H3K4me3) and repressive (H3K27me3 and H3K9me3) histone modifications in naive CD8 T cells (TN), TMEM and TEX. We identified H3K27ac-associated super-enhancers that distinguish TN, TMEM and TEX, along with key transcription factor networks predicted to regulate these different transcriptional landscapes. Promoters of some key genes were poised in TN, but activated in TMEM or TEX whereas other genes poised in TN were repressed in TMEM or TEX, indicating that both repression and activation of poised genes may enforce these distinct cell states. Moreover, narrow peaks of repressive H3K9me3 were associated with increased gene expression in TEX, suggesting an atypical role for this modification. These data indicate that beyond chromatin accessibility, hPTMs differentially regulate specific gene expression programs of TEX compared to TMEM through both activating and repressive pathways.

Chromosome-level genome assembly and annotation of Gypsophila vaccaria

Gypsophila vaccaria Sm., a member of the Caryophyllaceae family, is known for its dry mature seeds, which are widely used in traditional Chinese medicine as "Wang Bu Liu Xing". This study presents a high-quality, chromosome-scale genome assembly of G. vaccaria, integrating Hi-C technology with PacBio and Illumina sequencing data. The final assembled genome measures 1.09 Gb in total length, with a contig N50 of 9.73 Mb and a scaffold N50 of 73.3 Mb, and complete benchmarking universal single-copy orthologs (BUSCO) for the genome and protein modes were 95.9% and 94.9%. Notably, 99.93% of the sequences are anchored to 15 pseudo-chromosomes. A total of 21,795 protein-coding genes were predicted, and repetitive elements were found to constitute 80.43% of the assembled genome. This chromosome-level genome assembly serves as an invaluable resource for future research, including functional genomics and molecular breeding of G. vaccaria.

The regulatory landscape of 5' UTRs in translational control during zebrafish embryogenesis

The 5' UTRs of mRNAs are critical for translation regulation during development, but their in vivo regulatory features are poorly characterized. Here, we report the regulatory landscape of 5' UTRs during early zebrafish embryogenesis using a massively parallel reporter assay of 18,154 sequences coupled to polysome profiling. We found that the 5' UTR suffices to confer temporal dynamics to translation initiation and identified 86 motifs enriched in 5' UTRs with distinct ribosome recruitment capabilities. A quantitative deep learning model, Danio Optimus 5-Prime (DaniO5P), identified a combined role for 5' UTR length, translation initiation site context, upstream AUGs, and sequence motifs on ribosome recruitment. DaniO5P predicts the activities of maternal and zygotic 5' UTR isoforms and indicates that modulating 5' UTR length and motif grammar contributes to translation initiation dynamics. This study provides a first quantitative model of 5' UTR-based translation regulation in development and lays the foundation for identifying the underlying molecular effectors.

A telomere-to-telomere genome assembly of Camellia nitidissima

Camellia nitidissima is the model species of the Camellia sect. Chrysantha Chang, the only lineage within the genus Camellia known to produce golden-yellow flowers. This species holds high aesthetic, germplasm and medical value. Unfortunately, due to excessive collection and habitat loss, C. nitidissima is classified as a critically endangered plant. In this study, we assembled a telomere-to-telomere (T2T) genome of C. nitidissima by incorporating PacBio HiFi and Hi-C data. The assembled genome consisted of 15 pseudo-chromosomes, with a total size estimated to be 2.72 Gb. The GC content and repetitive sequences occupied 38.05% and 84.38% of the assembled genome, respectively. In total, 35,701 protein-coding genes were annotated. Multiple evaluation methods confirmed the contiguity (contig N50: 81.74 Mb), completeness (BUSCOs: 98.80%) and high LTR Assembly Index (LAI: 14.57) of the genome. This high-quality T2T genome will provide valuable insights into the genomic characteristics of C. nitidissima and facilitate conservation efforts as well as functional genomic studies in Camellia sect. Chrysantha species.

Whole-Genome Resequencing Analysis of Copy Number Variations Associated with Athletic Performance in Grassland-Thoroughbred

Copy number variation (CNV) is an important source of genetic variation. However, studies utilizing whole-genome sequencing to investigate CNVs in horse populations and their effects on traits remain relatively limited. This study aims to address the lack of research on the impact of copy number variation (CNV) on racing performance in horse populations, providing new insights for locally bred racing breeds. We analyzed 60 offspring derived from the crossbreeding of Thoroughbred horses and Xilingol horses. These horses were temporarily named "Grassland-Thoroughbred" and were divided into two groups: 30 racing horses and 30 non-racing horses. A total of 89,527 CNVs were identified. After merging overlapping CNVs, 982 copy number variation regions (CNVRs) were recognized, among which the racing horse group (RH) had 29 unique CNVRs, while the non-racing horse group (NR) had 4 unique CNVRs. In addition, a total of 195 genes overlapping with CNVRs were identified. Transcriptomic analysis revealed 120 differentially expressed genes, with MTPN expressed in both CNVR-overlapping genes and mRNA. Both CNVR-overlapping genes and differentially expressed genes were enriched in the MAPK signaling pathway; CNV may affect gene expression through gene dosage effects or regulatory mechanisms. Using Vst statistical analysis, we further screened candidate CNVRs in autosomes that exceeded the 95% differentiation threshold between the RH and NR populations. Several key genes associated with energy metabolism and muscle function were identified, including AGT, IGFN1, IMMPL2, SLC41A3, AOX4, and ACAD11. These findings provide new insights into the genetic structural variation in racing performance and adaptability, fill the gap in CNV studies in the genomics of Grassland-Thoroughbred horses, and offer valuable genomic data for optimizing breeding strategies in native racing horse populations.

Genetic Isolation among Four Lineages of Silene nutans

Speciation is the process leading to the emergence of new species. While being usually progressive, it can sometimes be fast with rapid emergence of reproductive barriers leading to high level of reproductive isolation. Some reproductive barriers might leave signatures in the genome, through elevated level of genetic differentiation at specific loci. Similar signatures might also be the results of linked selection acting in low recombination regions. Nottingham catchfly (Silene nutans) is a Caryophyllaceae species composed of four genetically differentiated lineages for which strong and asymmetric levels of reproductive isolation have been identified. Using population transcriptomic data from several individuals of the four lineages, we inferred the best evo-demographic scenario leading to the current reproductive isolation of these four lineages. We also tested whether loci exhibiting high level of genetic differentiation represented barrier loci or were located in low recombination regions, evolving under strong influence of linked selection. Overall, the four lineages of S. nutans have diverged in strict isolation, likely during the different glacial period, through migration in distinct glacial refugia. Speciation between these four lineages appeared to be particularly fast, likely due to fast evolving plastid genome accelerating plastid-nuclear co-evolution and the probability of plastid-nuclear incompatibilities in inter-lineage hybrids.

Transcriptome data from the interdigital webs of the Chinese Soft-shell Turtle (Pelodiscus sinensis)

The interdigital webs of aquatic tetrapods are a key structure evolved for adaptation, which are formed by inhibiting interdigital cell death (ICD). Diverse interdigital morphologies have independently evolved among species, and the regulatory mechanisms responsible for their development are still not fully understood. The Chinese soft-shell turtle (Pelodiscus sinensis) serves as a good research model that exhibits transitional traits from webless to fully webbed. In this study, we collected eight samples of interdigital webs from the fore- and hindlimbs of turtles at embryonic stage 19 (TK19) for RNA sequencing (RNA-seq) analysis. We identified 608 differentially expressed genes (DEGs). Whole-mount in situ hybridization (WISH) and real-time quantitative PCR (RT-qPCR) of representative genes confirmed the accuracy of the transcriptomic results. These findings not only provide new perspectives and data to support comparative studies of adaptive convergent evolution in aquatic animals but also enhance our understanding of the mechanisms underlying tetrapod limb morphogenesis. Furthermore, these results provide potential molecular targets for research on the plasticity of programmed cell death or senescence.

Chromosome-level genome assembly of the parasitoid wasp Aenasius arizonensis

Aenasius arizonensis is an important solitary endoparasitoid successfully used for biocontrol of cotton mealybug. However, lacking genomic resources has limited molecular-level investigations. Our exploration produced a superior genomic assembly of A. arizonensis from the chromosome level by combining MGISEQ short reads, Hi-C scaffolding, and PacBio Revio sequencing techniques. The genome measured 398.69 Mb, including a contig N50 of 4.73 Mb, a BUSCO completeness level of 97.07%, and a scaffold N50 of 35.96 Mb. Hi-C data were further utilized cluster and anchor 98.66% of the genome sequences into 11 chromosomes. Approximately, 165.90 Mb, representing about 41.61% of the genome, was identified as repeat elements. Non-coding sequence annotation identified 171 rRNAs, 117 small RNAs, 331 regulatory RNAs, and 872 tRNAs. Genome annotation reveals 11,727 protein-coding genes, with 10,842 (92.45%) genes functionally annotated. In summary, our chromosome-level genome assembly serves as a significant resource for advancing research on Encyrtidae parasitoids.

New insights into tumor microenvironment and HPV integrations in cervical cancer pathogenesis revealed by single-cell transcriptome data

HPV infection is common among women and can result in serious illnesses. This research utilizes single-cell RNA-sequencing (scRNA-seq) to study the connection between cellular heterogeneity and HPV integrations in cervical histopathology. scRNA-seq was used to examine heterogeneity among normal patients and those in three disease stages: high-grade squamous intraepithelial lesions (HSIL), microinvasive carcinoma (MIC), and cervical squamous epithelium carcinoma cancer (CSCC) tissues. A method was developed to identify HPV integration events from scRNA-seq data. Our results indicated an increase in squamous epithelial cells and a decrease in columnar epithelial cells as the disease progressed from normal to CSCC. We discovered HPV genes that were differentially expressed across normal patients and those in the three disease stages. Notably, HPV integration events were more common in squamous epithelial cells at the single-cell level. The ratio of HPV-integrated cells increased as the disease progressed from normal tissue to CSCC, eventually stabilizing. Several genes, such as EGR1, S100A11, S100A8, KRT5, RPL34, ATP1B1, RPS4X and EEF2, were frequently integrated by HPV across patients. In contrast, genes like PAN3, BABAM2, SPEN, TCIM-SIRLNT, TEX41-PABPC1P2 and KCNV1-LINC01608 showed frequent integration events across cells. KRT5, ATP1B1, RPS4X, PAN3 and SPEN were novel recurrent HPV-integrated genes we observed at the patient or cell level in this study. Additionally, we found that HPV genes from various HPV types exhibited integration preferences in various samples and disease stages. This provides a valuable insight into the mechanism of HPV-induced cervical cancer from a single-cell standpoint, highlighting its clinical relevance.

DNA Methylation and Alternative Splicing Safeguard Genome and Transcriptome After a Retrotransposition Burst in Arabidopsis thaliana

Transposable elements (TEs) are major drivers of plant genome plasticity, but the immediate molecular consequences of new TE insertions remain poorly understood. In this study, we generated a wild-type Arabidopsis thaliana population with novel insertions of ONSEN retrotransposon to investigate early epigenomic and transcriptomic changes using whole-genome and cDNA nanopore sequencing. We found that novel ONSEN insertions were distributed non-randomly, with a strong preference for genic regions, particularly in chromatin enriched for H2A.Z, H3K27me3, and H3K4me2. Most full-length ONSEN insertions within genes were rapidly recognized and spliced out as new introns (intronization), thereby mitigating potential deleterious effects on transcript isoforms. In some cases, ONSEN insertions provided alternative transcription start or termination sites, generating novel transcript isoforms. Genome-wide methylation analysis revealed that new ONSEN copies were efficiently and precisely targeted by DNA methylation. Independently on the location of the original ONSEN element, the euchromatic and heterochromatic insertions display distinct methylation signatures, reflecting the action of different epigenetic pathways. In conclusion, our results demonstrate that DNA methylation and alternative splicing are effective control mechanisms safeguarding the plant genome and transcriptome integrity after retrotransposition burst.

Transcriptomics Reveals an Energy-Saving Metabolic Switch in an Extremophilic Red Microalga Cyanidioschyzon merolae Under Nickel Stress

The red microalga Cyanidioschyzon merolae inhabits extreme environments with high temperatures (40-56 °C), high acidity (pH 0.05-4), and high concentrations of heavy metals that are lethal to most forms of life. However, information is scarce on the precise adaptation mechanisms of this extremophile to such hostile conditions. Gaining such knowledge is important for understanding the evolution of microorganisms in the early stages of life on Earth characterized by such extreme environments. Through an analysis of the re-programming of the global transcriptome upon the long-term (up to 15 days) exposure of C. merolae to extremely high concentrations of nickel (1 and 3 mM), the key adaptive metabolic pathways and associated molecular components were identified. Our work shows that the long-term Ni exposure of C. merolae leads to the lagged metabolic switch demonstrated via the transcriptional upregulation of the metabolic pathways critical for cell survival. DNA replication, cell cycle, and protein quality control processes were upregulated, while downregulation occurred with energetically costly processes, including the assembly of the photosynthetic apparatus and lipid biosynthesis. This study paves the way for future multi-omic studies of the molecular mechanisms of abiotic stress adaptation in phototrophs, as well as the future development of rational approaches to the bioremediation of contaminated aquatic environments.

Identifying rhizosphere bacteria and potential mechanisms linked to compost suppressiveness towards Fusarium oxysporum

BACKGROUND

Soilborne fungal phytopathogens pose a significant threat to global food security. While chemical control remains an effective method for managing these pathogens, increasing regulations due to health and environmental concerns, along with rising fungicide resistance, have restricted their use, underscoring the urgent need for sustainable alternatives. The use of compost to enhance soil fertility and suppress plant diseases is well documented. Several studies have underlined the role of microorganisms in disease suppression, but the mechanisms facilitating this disease suppression remain unclear. We evaluated the impact of compost amendment on the composition and functional capacity of the rhizosphere microbiome in cucumber plants (Cucumis sativus) inoculated with Fusarium oxysporum f. sp. radicis-cucumerinum (FORC) under controlled greenhouse conditions using amplicon sequencing, shotgun metagenomic and culture-based techniques.

RESULTS

Compost amendment significantly reduced FORC-induced disease in cucumber relative to non-amended treatments. While FORC inoculation resulted in significant shifts in microbial (bacterial and fungal) community composition in the rhizosphere of non-amended plants, this phenomenon was substantially less pronounced in the rhizosphere of compost-amended plants. Specifically, compost amendment sustained the presence of Actinomycetota (Streptomyces, Actinomadura, Saccharomonospora, Pseudonocardia, Glycomyces, Thermobifida) and Bacillota (Planifilum, Novibacillus) in FORC inoculated plants, that diminished significantly in inoculated plants without compost. These taxa contained a myriad of non-ribosomal peptides and polyketides synthetases biosynthetic gene clusters (BGCs) with putative antimicrobial and iron-chelating functions. We successfully isolated two Streptomyces strains from FORC-suppressing compost amended rhizospheres that were almost identical to the Streptomyces bin2 (99% ortho ANI) metagenome assembled genome identified in the shotgun metagenome analysis. These strains produced extracellular metabolites that inhibited growth of FORC in-vitro and contained BGCs that encode for compounds with potential antimicrobial capacity.

CONCLUSIONS

Based on results presented in this study, we demonstrate that compost alleviates FORC-induced dysbiosis of the rhizosphere microbiome, maintaining abundance of specific bacterial taxa. These bacterial groups may contribute to disease suppression through a myriad of mechanisms including iron chelation and production of fungal antagonizing secondary metabolites.

The critical role of BMP signaling in gastric epithelial cell differentiation revealed by organoids

The efficient differentiation of adult gastric stem cells into specific epithelial cell types is crucial for gastric homeostasis. Although it is well appreciated that the niche plays a critical role in gastric epithelium cell differentiation, the relevant molecular factors and the underlying regulatory mechanisms remain poorly understood. In this study, by combining the knowledge of the niche cells obtained from single-cell RNA sequencing and manipulation of signaling pathways, we achieved effective differentiation of various gastric epithelial cell types in mouse and human gastric organoids. These in vitro differentiated cells showed a similar gene expression profile to those in gastric tissues. Specifically, BMP4 signaling stimulates pit cell and parietal cell differentiation. Furthermore, BMP4 and EGF signaling cooperate to enhance pit cell differentiation, whereas inhibition of TGF-β and BMP4 signaling promotes chief cell differentiation. We demonstrated that Zbtb7b is a novel regulator controlling pit cell differentiation. In addition, BMP4, together with the small molecule Isoxazole 9, promotes parietal and enteroendocrine cell differentiation. Our data also revealed the different requirements of parietal and chief cell differentiation between mouse and human. Together, our findings provide a mechanistic insight into gastric epithelial cell differentiation and uncover its similarities and differences between mouse and human, laying a foundation for future investigation and potential clinical use of gastric organoids.

Consecutive low-frequency shifts in A/T content denote nucleosome positions across microeukaryotes

Nucleosomes are the basic repeating unit, each spanning ≈150bp, that structures DNA in the nucleus and their positions have major consequences on gene activity. Here, through analyzing DNA signatures across 1117 microeukaryote genomes, we discovered ≈150bp shifts in A/T content associated with nucleosome organization. Often consecutively arrayed across the genome, A/T peaks were enriched surrounding transcriptional start sites in specific clades. Most nucleosomes (both in vitro and in vivo) across eukaryotes aligned with A/T peaks, even in the presence of DNA modifications. Using artificial intelligence-based approaches, we describe DNA features associated with nucleosomes and construct a deep learning (DL) model for improved nucleosome occupancy prediction. Using this model, we found that ≈70% of "random" transfer DNA inserts from an in vivo fungal RB-TDNAseq library avoided DL predicted nucleosome-bound regions. This study reveals a eukaryote-wide strategy for generating cassettes of nucleosome-favorable DNAs that has a profound impact on nucleosome organization.

scRNA-seq reveals transcriptional plasticity of var gene expression in Plasmodium falciparum for host immune avoidance

Plasmodium falciparum evades antibody recognition through transcriptional switching between members of the var gene family, which encodes the major virulence factor and surface antigen on infected red blood cells. Previous work with clonal P. falciparum populations revealed var gene expression profiles inconsistent with uniform single var gene expression. However, the mechanisms underpinning this and how it might contribute to chronic infections were unclear. Here, using single-cell transcriptomics employing enrichment probes and a portable microwell system, we analysed var gene expression in clonal 3D7 and IT4 parasite lines. We show that in addition to mono-allelic var gene expression, individual parasites can simultaneously express multiple var genes or enter a state in which little or no var gene expression is detectable. Reduced var gene expression resulted in greatly decreased antibody recognition of infected cells. This transcriptional flexibility provides parasites with greater adaptive capacity and could explain the antigenically 'invisible' parasites observed in chronic asymptomatic infections.

Identification and characterization of the de novo methyltransferases for eukaryotic N6-methyladenine (6mA)

N6-methyladenine (6mA) is an intensively investigated epigenetic modification in eukaryotes. 6mA is maintained through semiconservative transmission during DNA replication, but the identity of de novo methyltransferase (MTase) catalyzing its establishment remains unknown. Here, we identified MT-A70 family proteins AMT2 and AMT5 as the de novo MTases responsible for 6mA establishment, using the unique sexual reproduction process of the unicellular eukaryote Tetrahymena thermophila. Deletion of AMT2 and AMT5 led to a substantial decrease in 6mA levels in the progeny macronucleus, resulting in an altered gene expression pattern and a substantial decline in the survival rate of sexual progenies. Additionally, the maintenance MTase AMT1 could exhibit a much diminished de novo methylation activity in cells lacking AMT2 and AMT5. Our study delineated the establishment-maintenance pathway of 6mA and underscored the biological importance of de novo methylation, revealing a notable parallel between 6mA and the classical 5-methylcytosine in eukaryotes.

Genomic characterization of the novel bacteriophage PfAn1 from Lake Baikal, infecting Pseudomonas fluorescens

We isolated a novel bacteriophage from Lake Baikal that infects Pseudomonas fluorescens. Transmission electron microscopy revealed that phage PfAn1 has a head with a diameter of 50 nm and a short tail. Its genome is 39,156 bp in length with a GC content of 57%. It is predicted to contain 53 open reading frames (ORFs). The results of evolutionary analysis suggest that phage PfAn1 should be considered a new member of the class Caudoviricetes.