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At least 289 records · Page 16Linked to original sources

Chromosome-level Genome Assembly of the Halophytic Turfgrass Zoysia macrostachya.

Zoysia macrostachya Franch. & Sav. is a halophytic perennial turfgrass in the Poaceae family, commonly found in the coastal regions of Korea, Japan, and East Asia. Z. macrostachya thrives in high-salinity environments, making it an excellent model for studying abiotic stress resilience. In this study, we present a chromosome-level genome assembly of Z. macrostachya, constructed using Oxford Nanopore long reads, Illumina short reads, and Omni-C sequencing data. The assembly spans 329.78 Mb across 20 chromosomes, with a scaffold N50 of 19.24 Mb, and includes complete telomeric sequences at both ends. The assembly showed 97.8% complete BUSCOs, indicating high genome completeness. Repeat element and gene annotation identified 44.03% of the genome as repetitive elements and 33,474 protein-coding genes. The gene annotation showed 97.1% complete BUSCOs and 86.92% functionally characterized genes. Macrosynteny analysis highlighted highly collinear relationships with related species, providing a foundational understanding of the Z. macrostachya genomic structure. This high-quality genome serves as a valuable resource for advancing salinity tolerance research and improving the genetic diversity of Zoysia species.

Genome, Plant↗

Chromosomal-level genome assembly of Trypanosoma carassii, the etiologic agent of a recent outbreak of trypanosomiasis in cage-cultured large yellow croaker (Larimichthys crocea) in China.

Trypanosoma carassii, a typical freshwater fish trypanosome, has recently been identified as the etiological agent of a trypanosomiasis outbreak in cage-cultured large yellow croaker (Larimichthys crocea) in China and has been designated as T. c. larimichthys. To date, publicly available genomic data for trypanosomes have been limited to terrestrial species, particularly those of medical importance. Here, we present a chromosome-level genome assembly of T. carassii, the first genome of an aquatic trypanosome, generated using PacBio HiFi long-read sequencing and Hi-C scaffolding technologies. A preliminary genome survey based on Illumina sequencing data estimated the genome size at 56.38 Mb with a heterozygosity of 1.17%. The final assembled genome spans 48.55 Mb, with contig N50 and scaffold N50 values of 139.15 Kb, and achieves 100.00% BUSCO completeness. Hi-C data resolved the assembly into 34 chromosomes and 9 unanchored scaffolds. Repetitive elements account for 53.29% of the genome (approximately 25.87 Mb). A total of 11,584 protein-coding genes were predicted, 95.36% of which were functionally annotated. Synonymous substitution rates analysis of paralogous genes indicates a recent burst of gene duplication, which likely corresponds to a whole-genome duplications. This high-quality genome assembly provides invaluable resources for understanding the evolution and host adaptation of aquatic trypanosomes.

Animals↗

Chromosome-level genome assembly and annotation of the porcupine fish (Diodon hystrix).

The porcupinefish (Diodon hystrix), a coral reef teleost, is widely distributed in tropical/subtropical waters of the Pacific, Atlantic, Indian Oceans, and Mediterranean Sea. It shares easily recognizable features with pufferfish, such as body inflation and spines. Additionally, its culinary value makes D. hystrix a highly desirable species in many tropical coastal regions, with considerable market potential. However, lack of a high-quality genome hindered further studies on its reproduction, molecular biology, and genomic improvement. Here, we assembled the chromosome-scale genome using PacBio HiFi, ultra-long reads, and Hi-C. Of the 713.62 Mb genome, 98.63% anchored to 23 chromosomes (scaffold N50: 31.52 Mb) with 39.82% repetitive sequences. The assembled genome achieved a BUSCO completeness score of 97.7%, with 23,171 protein-coding genes predicted, 22,221 of which were functionally annotated. Phylogenetic analysis identified D. hystrix's evolutionary relationships with other species in the Tetraodontiformes. In summary, the high-quality genome of D. hystrix sheds light on valuable insights into genome size evolution, and provides a valuable resource for exploiting genomic study and breeding applications in this species.

Animals↗

Pan-genome based on chromosome sequences of wild and cultivated Agaricus bisporus.

Agaricus bisporus, one of the most widely cultivated mushrooms around the world, plays an important role in economy and agriculture. In this study, by employing long-reads generated by PacBio and Nanopore sequencing, we assembled six novel high-quality genomes (of which three are telomere-to-telomere assemblies) with sizes 29.6 ~ 30.8 Mb and N50 lengths of 2.5 ~ 2.6 Mb. Combined with public genome data of nine strains, we successfully established a pan-genome of A. bisporus, comprising a total of 14,626 clusters of protein coding genes, of which 50.70%, 7.45%, 24.74% and 17.01% are defined as core, soft core, dispensable, and private clusters, respectively. A total of 5,646 non- redundant structural variants (SVs) were identified among wild and cultivated strains and the genes associated with SV were mapped. This work provides valuable whole-genome sequences and genomic resources across wild and cultivated strains of the most widely cultivated mushroom species for functional analyses of genomes.

Agaricus↗

High-Resolution Chromosome-Level Genome Assembly and Annotation of Triplophysa stewarti, an Endemic Plateau Loach from the Qinghai-Tibet Plateau.

The bottom-dwelling fish Triplophysa stewarti, endemic to the Qinghai-Tibet Plateau, is a valuable model for studying high-altitude adaptation in aquatic ecosystems. However, the lack of a high-quality reference genome has hindered comparative genomic and evolutionary studies within this genus. Here, we present a chromosome-level genome assembly for T. stewarti, generated using PacBio HiFi long-read sequencing and Hi-C scaffolding. The 697.9 Mb assembly is highly continuous (scaffold N50 of 253.58 Mb) and encompasses 25 chromosomes, representing 92.65% of the genome. BUSCO analysis indicated a 98.4% completeness, supporting the high quality of the assembly. We annotated 28,009 protein-coding genes, with 97.04% being functionally assigned across multiple databases (NR, UniProt, KEGG, GO, Pfam and InterPro). Additionally, repetitive elements constituted 42.47% of the genome, and we identified 52,709 non-coding RNAs. This high-quality reference genome provides a fundamental resource for exploring the adaptive evolution, population structure, and conservation genetics of T. stewarti and related species on the Qinghai-Tibet Plateau.

Animals↗

Chromosome-level genome assembly of the hemiparasitic Taxillus sutchuenensis (Loranthaceae).

Taxillus sutchuenensis, an ecologically and medicinally important hemiparasitic plant that parasitizes diverse woody hosts, was sequenced to generate a high-quality chromosome-level genome assembly. PacBio HiFi long reads, RNA-seq transcriptome data, and Hi-C data were used to assemble a 406.32 Mb genome anchored onto nine pseudo-chromosomes, with a scaffold N50 of 45.59 Mb. The assembly showed high completeness and accuracy, supported by BUSCO (93.6%) and Merqury QV (70.6) assessments. The LTR Assembly Index (LAI) of 13.98 indicated excellent continuity. A total of 21,795 protein-coding genes were predicted, with 94.46% functionally annotated. Repetitive sequences accounted for 50.05% of the genome, primarily LTR retrotransposons. This genome provides a valuable resource for investigating the evolution, functional genomics, and parasitic mechanisms of hemiparasitic plants.

Genome, Plant↗

A high-quality chromosome-level genome assembly of apple of Peru (Nicandra physalodes).

Nicandra physalodes, a member of the Solanaceae family, is known for its medicinal potential and strong natural insect-repellent properties, which are mainly attributed to its bioactive withanolides and alkaloids. Despite its ecological and pharmacological significance, genomic information for this species has remained limited. Here, we generated a chromosome-level reference genome for N. physalodes based on PacBio high-fidelity (HiFi) long-read sequencing and Hi-C scaffolding. The assembled genome is 933.97 Mb in size, with a contig N50 of 87.37 Mb, and 99.95% (933.54 Mb) of the sequences anchored to 10 pseudochromosomes. Repetitive elements account for 73.06% of the genome, and 27,925 protein-coding genes were predicted, 97.81% of which were functionally annotated. This genomic resource provides a valuable foundation for investigating the genetic basis of specialized metabolite biosynthesis, insect resistance, and environmental adaptation in N. physalodes, as well as for comparative studies within the Solanaceae family.

Genome, Plant↗

Chromosome-level genome assembly of the horned turban snail Turbo cornutus.

The horned turban snail (Turbo cornutus) is an ecologically and economically important herbivorous gastropod inhabiting nearshore rocky reef habitats. T. cornutus represents a valuable coastal fishery resource in East Asia. Here, we present a chromosome-level genome assembly for T. cornutus generated using a combination of PacBio HiFi long-read and Illumina short-read sequencing and Hi-C scaffolding. The assembled genome spanned 1.93 Gb and was organized into 18 pseudo-chromosomes, representing 99.50% of the total assembly. The contig and scaffold N50 lengths were 41.02 Mb and 104.01 Mb, respectively, with repeat sequences constituting 59.07% of the genome. A total of 28,920 protein-coding genes were predicted, and genome completeness was assessed at 99.3% using the BUSCO mollusca_odb12 dataset. This chromosome-level genome assembly provides a reference for future studies on the biology of T. cornutus, the organization of the gastropod genome, and comparative genomics.

Animals↗

A gap-free, telomere-to-telomere chromosome-scale genome assembly of the mangrove red snapper, Lutjanus argentimaculatus.

The mangrove red snapper (Lutjanus argentimaculatus) is a commercially important marine fish species in the Indo-Pacific region. Despite its significant economic value for aquaculture, existing genomic resources remain fragmented, limiting the advancement of molecular breeding and functional genomic studies. Here, we present a gap-free, telomere-to-telomere (T2T) genome assembly of L. argentimaculatus, generated using a hybrid approach combining PacBio HiFi, Oxford Nanopore ultra-long reads and Hi-C technology. The resulting assembly comprises exactly 24 scaffolds spanning 1.03 Gb, perfectly matching the haploid chromosome number with a contig N50 of 46.17 Mb. Notably, this assembly resolves all physical gaps present in previous versions, achieving a BUSCO completeness score of 98.2%. Comprehensive genome annotation successfully predicted 23,167 protein-coding genes. Among these, 22,067 genes (95.25%) were functionally annotated across major public databases, including eggNOG, InterPro, and Swiss-Prot. Furthermore, structural analysis successfully identified 19 telomeres and 20 centromeres, validating the chromosomal integrity. This high-fidelity, gap-free reference genome provides a robust foundation for comparative genomics, population genetics, and the genetic improvement of Lutjanidae species.

Animals↗

The emergence and diversification of the DUX gene family across placental mammals.

The DUX gene family encodes transcription factors with paired homeodomains. It has critical roles in embryogenesis and disease, including facioscapulohumeral muscular dystrophy (FSHD) and cancer. This study conducts a comparative analysis of the DUX gene family-DUXA, DUXB (including DUXBL), and DUXC (including DUX4 and Dux)-across placental mammals, highlighting their structural diversity within macrosatellite repeat contexts. Using long-read genomes, we explore gene distribution, array patterns, and phylogenetic relationships in various vertebrate species. Our analysis reveals that DUXA and DUXB are highly conserved, with intriguing variations such as intronless forms likely arising from ancestral retrotransposition events. While DUXBL is inconsistently retained across clades, its locus-which in non-placental mammals harbors the ancestral single-homeodomain sDUX gene-served as an evolutionary hub for diversification, giving rise to DUXA, DUXB and DUXC, as well as macrosatellite tandem array structures. Sequence conservation and syntenic analyses demonstrate array adaptability, exemplified by higher-order repeats in orangutans and disrupted patterns of concerted evolution in elephants. Furthermore, analysis of human pseudo-DUX4 arrays indicates their potential role in disease mechanisms, including as possible contributors to rare cases of FSHD, warranting further investigation. This study thus provides insights into DUX-family gene evolution, offering a foundation for future research into developmental roles and disease implications.

Animals↗

The carB gene of Escherichia coli: a duplicated gene coding for the large subunit of carbamoyl-phosphate synthetase.

Previous genetic and biochemical studies indicate that the carB gene of Escherichia coli codes for the large subunit of carbamoyl-phosphate synthetase (EC 6.3.5.5). We have determined the nucleotide sequence of a 4-kilobase-pair cloned fragment of E. coli DNA with genetic determinants for carB. The DNA sequence is a 3,219-nucleotide-long reading frame. The polypeptide encoded by this reading frame has been verified to be the large subunit of carbamoyl-phosphate synthetase. The gene product is similar to the large subunit in its molecular weight, amino acid composition and amino-terminal residue, and carboxyl-terminal sequence. The amino acid sequence derived from the nucleotide sequence shows a highly significant homology between the amino- and carboxyl-terminal halves of the protein. We propose that the carB gene was formed by an internal duplication of a smaller ancestral gene.

Amino Acid Sequence↗

Molecular cloning of a cDNA encoding interleukin 11, a stromal cell-derived lymphopoietic and hematopoietic cytokine.

Hematopoiesis occurs in close association with a complex network of cells loosely termed the hematopoietic microenvironment. Analysis of the mechanisms of microenvironmental regulation of hematopoiesis has been hindered by the complexity of the microenvironment as well as the heterogeneity of hematopoietic stem cells and early progenitor cells. We have established immortalized primate bone marrow-derived stromal cell lines to facilitate analysis of the interactions of hematopoietic cells with the microenvironment in a large animal species. One such line, PU-34, was found to produce a variety of growth factors, including an activity that stimulates the proliferation of an interleukin 6-dependent murine plasmacytoma cell line. A cDNA encoding the plasmacytoma stimulatory activity was isolated through functional expression cloning in mammalian cells. The nucleotide sequence contained a single long reading frame of 597 nucleotides encoding a predicted 199-amino acid polypeptide. The amino acid sequence of this cytokine, designated interleukin 11 (IL-11), did not display significant similarity with any other sequence in the GenBank data base. Preliminary biological characterization indicates that in addition to stimulating plasmacytoma proliferation, IL-11 stimulates the T-cell-dependent development of immunoglobulin-producing B cells and synergizes with IL-3 in supporting murine megakaryocyte colony formation. These properties implicate IL-11 as an additional multifunctional regulator in the hematopoietic microenvironment.

Amino Acid Sequence↗

Effects of generation on immediate memory span and delayed unexpected free recall.

We investigated the effects of generating words from fragments on pronunciation time, on immediate memory span, and on delayed free recall. Subjects read long words and short words aloud or generated them from strings with missing letters. Word-length and generation condition had multiplicative effects on speaking rate, as expected if each affected a separate process regulating the rate. We replicated the standard finding that span is smaller for longer words. Generation improved delayed free recall, indicating that relatively brief presentation times are adequate to produce a generation effect. Although generation improved long-term memory for the words, memory span was shorter for the words that were generated. The harmful effect of generation on span appears to be due to its slowing of speaking rate.

Analysis of Variance↗

Generating multiple alignments on a pangenomic scale.

MOTIVATION: Since novel long read sequencing technologies allow for de novo assembly of many individuals of a species, high-quality assemblies are becoming widely available. For example, the recently published draft human pangenome reference was based on assemblies composed of contigs. There is an urgent need for a software-tool that is able to generate a multiple alignment of genomes of the same species because current multiple sequence alignment programs cannot deal with such a volume of data. RESULTS: We show that the combination of a well-known anchor-based method with the technique of prefix-free parsing yields an approach that is able to generate multiple alignments on a pangenomic scale, provided that large-scale structural variants are rare. Furthermore, experiments with real world data show that our software tool PANgenomic Anchor-based Multiple Alignment significantly outperforms current state-of-the art programs. AVAILABILITY AND IMPLEMENTATION: Source code is available at: https://gitlab.com/qwerzuiop/panama, archived at swh:1:dir:e90c9f664995acca9063245cabdd97549cf39694.

Software↗

wgatools: an ultrafast toolkit for manipulating whole-genome alignments.

SUMMARY: With the rapid development of long-read sequencing technologies, the era of individual complete genomes is approaching. We have developed wgatools, a cross-platform, ultrafast toolkit that supports a range of whole-genome alignment formats, offering practical tools for conversion, processing, evaluation, and visualization of alignments, thereby facilitating population-level genome analysis and advancing functional and evolutionary genomics. AVAILABILITY AND IMPLEMENTATION: wgatools supports diverse formats and can process, filter, and statistically evaluate alignments, perform alignment-based variant calling, and visualize alignments both locally and genome-wide. Built with Rust for efficiency and safe memory usage, it ensures fast performance and can handle large datasets consisting of hundreds of genomes. wgatools is published as free software under the MIT open-source license, and its source code is freely available at https://github.com/wjwei-handsome/wgatools and https://zenodo.org/records/14882797.

Software↗

DNABERT-S: pioneering species differentiation with species-aware DNA embeddings.

SUMMARY: We introduce DNABERT-S, a tailored genome model that develops species-aware embeddings to naturally cluster and segregate DNA sequences of different species in the embedding space. Differentiating species from genomic sequences (i.e. DNA and RNA) is vital yet challenging, since many real-world species remain uncharacterized, lacking known genomes for reference. Embedding-based methods are therefore used to differentiate species in an unsupervised manner. DNABERT-S builds upon a pre-trained genome foundation model named DNABERT-2. To encourage effective embeddings to error-prone long-read DNA sequences, we introduce Manifold Instance Mixup (MI-Mix), a contrastive objective that mixes the hidden representations of DNA sequences at randomly selected layers and trains the model to recognize and differentiate these mixed proportions at the output layer. We further enhance it with the proposed Curriculum Contrastive Learning (C2LR) strategy. Empirical results on 28 diverse datasets show DNABERT-S's effectiveness, especially in realistic label-scarce scenarios. For example, it identifies twice more species from a mixture of unlabeled genomic sequences, doubles the Adjusted Rand Index (ARI) in species clustering, and outperforms the top baseline's performance in 10-shot species classification with just a 2-shot training. AVAILABILITY AND IMPLEMENTATION: Model, codes, and data are publically available at https://github.com/MAGICS-LAB/DNABERT_S.

Sequence Analysis, DNA↗

UMI-nea: a fast, robust tool for reference-free UMI deduplication and accurate quantification.

MOTIVATION: One of the key applications of Unique Molecular Identifiers (UMIs) in high-throughput sequencing is to correct for PCR amplification bias and removal of PCR duplicates, thereby improving quantification in DNA-seq and RNA-seq applications. Accurately grouping error-bearing UMIs that originate from the same input molecule through a UMI deduplication method is a critical step in this process. However, many existing UMI deduplication tools rely on simple Hamming distance comparisons or suboptimal clustering algorithms, often resulting in erroneous UMI groupings, particularly in error-prone long-read sequencing or ultra-high-depth short-read sequencing. RESULTS: We introduce UMI-nea, a tool that utilizes Levenshtein distance comparisons and a novel clustering approach to optimize multithreading workflows. Compared against three other indel-aware UMI deduplication tools, UMI-nea achieves more accurate UMI groupings with efficient run time. It demonstrates robust performance across diverse sequencing platforms, depths, and UMI lengths. Additionally, UMI-nea incorporates a data-guided adaptive UMI filter, further enhancing quantification accuracy. AVAILABILITY AND IMPLEMENTATION: UMI-nea is available on github https://github.com/Qiaseq-research/UMI-nea.git or Zenodo https://doi.org/10.5281/zenodo.16745758. Sequencing data are stored at https://qiagenpublic.blob.core.windows.net/umi-nea-datasets/.

High-Throughput Nucleotide Sequencing↗

MHASS: Microbiome HiFi Amplicon Sequencing Simulator.

SUMMARY: Microbiome HiFi Amplicon Sequence Simulator (MHASS) creates realistic synthetic PacBio HiFi amplicon sequencing datasets for microbiome studies, by integrating genome-aware abundance modeling, realistic dual-barcoding strategies, and empirically derived pass-number distributions from actual sequencing runs. MHASS generates datasets tailored for rigorous benchmarking and validation of long-read microbiome analysis workflows, including ASV clustering and taxonomic assignment. AVAILABILITY AND IMPLEMENTATION: Implemented in Python with automated dependency management, the source code for MHASS is freely available at https://github.com/rhowardstone/MHASS along with installation instructions. Our code is also published on Zenodo at https://doi.org/10.5281/zenodo.17486364. The data underlying this article are available on GitHub at https://github.com/rhowardstone/MHASS_evaluation/.

Software↗