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At least 73 records · Page 4Linked to original sources

The T2T genome assembly of watershield (Brasenia schreberi) unveils genomic insights into aquatic adaptation.

Watershield (Brasenia schreberi), belonging to Cabombaceae within the order Nymphaeales, represents one of the early-diverged angiosperm lineages. This perennial floating leaf freshwater aquatic plant features submerged juvenile leaves enveloped in a thick layer of transparent gelatinous mucilage, aiding in its resistance to aquatic stress. However, the evolutionary history of the mechanisms underlying its specific phenotype remains unclear. In this study, we present the telomere-to-telomere level genome of B. schreberi, unveiling that it underwent two rounds of whole-genome duplications (WGDs) and a recent whole-genome triplication, with the most ancient WGD being shared by Nymphaeaceae. WGD and dispersed duplication significantly contributed to the expansion of gene families, which are primarily associated with environmental adaptation. Additionally, we discovered that mature leaves primarily conduct photosynthesis and may transport nutrients to underwater juvenile leaves for polysaccharide synthesis. We also identified an ancestral broad expression pattern of ABC genes, and the similar expression of anthocyanin biosynthesis genes across all flower organs resulted in entirely purple flowers. Our findings deepen the understanding of the evolution of this specific aquatic plant phenotypes.

Genome, Plant↗

A high-quality chromosome-scale genome assembly of Xingan mandarin (Citrus reticulata 'Xingan'), a primitive Mandarin type.

Mandarin (Citrus reticulata) is broadly recognized as one of the foremost citrus crops globally. Our study identified the Xingan mandarin (Citrus reticulata 'Xingan') as a primitive type found near Maoer Mountain. This report provides a high-resolution, chromosome-scale genome assembly for the Xingan mandarin. The total size of the genome assembly is an impressive 325.12 Mb, including contig N50 and scaffold N50 values of 29.32 Mb and 29.62 Mb, respectively. Notably, we successfully anchored approximately 93.08% of the assembled sequences onto nine pseudochromosomes. Our predictions identified 30,581 protein-coding genes, 166 miRNAs, 415 tRNAs, 728 rRNAs, 325 snRNAs, and 659 snoRNAs. We were able to predict the functions of 27,242 genes, constituting 89.08% of the total protein-coding genes. A notable finding of our study was the high degree of genome synteny between the Xingan mandarin and the Mangshan mandarin (Citrus reticulata 'Mangshan'), reinforcing their genetic similarity. The acquisition of the chromosome-level genome for the Xingan Mandarin represents a significant milestone, laying an indispensable foundation for rigorous molecular investigations of this species. Moreover, it is poised to invigorate advanced research in comparative genomics within the Citrus genus.

Citrus↗

Chromosome level genome assembly and full-length transcriptome of blacktip trevally (Caranx heberi).

Caranx heberi (Bennett, 1830) commonly known as the blacktip trevally belongs to the family Carangidae and is a potential brackishwater aquaculture species. However, the limited genomic resources are hindering the efforts to study its genetic traits and their molecular basis. To bridge this gap, we generated a high-quality reference genome employing multiple sequencing strategies including PacBio Hifi reads (135x), Illumina short reads (150x), and Hi-C chromosome conformation capturing (180x). The high-quality genome assembly consisted of 159 scaffolds summing to 618.71 Mb and an N50 value of 26.72 Mb. Among these, 24 chromosome level scaffolds covered 97.5% of the total assembly. The genome contained 20.94% of repeat elements and 30,354 protein encoding genes. In addition, full-length transcriptomes were generated using the PacBio IsoSeq approach from seven tissues (gill, kidney, liver, muscle, heart, spleen, and intestine). The comprehensive genomic and transcriptomic resources developed in this study will facilitate the domestication and aquaculture development of C. heberi, as well as support research on its nutritional potential, ecological adaptations, and evolutionary biology.

Animals↗

A chromosomal-level genome assembly of Odontolabis cuvera Hope, 1842 (Coleoptera: Lucanidae).

The stag beetle (Coleoptera: Lucanidae) represents a captivating and evolutionarily significant group, regarded as one of the most basal lineages within the superfamily Scarabaeoidea. Despite their importance for studying beetle evolution and ecology, genomic resources for this family remain scarce. Here, we report a chromosome-level genome assembly of Odontolabis cuvera, generated by integrating PacBio HiFi, Illumina, and Hi-C data. The genome assembly spans 908.07 Mb, comprising 66 scaffolds (scaffold N50: 65.36 Mb) and 147 contigs (contig N50: 16.39 Mb). A total of 99.58% (904.22 Mb) of the assembly was anchored to 14 chromosomes. BUSCO analysis (insecta_odb10 dataset, n = 1,367) demonstrated high completeness, with 99.1% of conserved insect orthologs identified (98.3% single-copy, 0.8% duplicated). Repetitive elements accounted for 53.00% (281.28 Mb) of the genome, and a total of 18,332 protein-coding genes were annotated. This high-contiguity genome provides a critical foundation for uncovering the evolutionary mechanisms and ecological adaptations unique to Lucanidae.

Animals↗

A chromosome-level genome assembly of Coffea arabica L. var. 'Kona Typica'.

Coffea arabica L. var. 'Kona Typica' is renowned for its premium cup quality, but its vulnerability to pests and diseases limits production. To accelerate cultivar improvement, we generated a chromosome-level genome assembly of 'Kona Typica' using PacBio HiFi sequencing and Hi-C scaffolding technology. The final assembly spans 1.13 Gb, with a scaffold N50 of 50.50 Mb, organized into 22 chromosomes. BUSCO assessment indicated a high completeness at 99.1%. We annotated 65,458 protein-coding genes and identified 1,073,545 interspersed repeats, accounting for 65.16% of the genome. Analysis of transposon insertion ages revealed that most long terminal repeat retrotransposons proliferated after the polyploidization event. This high-quality genome assembly of 'Kona Typica' provides a valuable resource for exploring coffee genomic evolution and genetic mechanisms of complex traits, facilitating genomics studies and the development of improved coffee cultivars with enhanced disease resistance and quality traits.

Coffea↗

Quality assessment of maize assembled genomic islands (MAGIs) and large-scale experimental verification of predicted genes.

Recent sequencing efforts have targeted the gene-rich regions of the maize (Zea mays L.) genome. We report the release of an improved assembly of maize assembled genomic islands (MAGIs). The 114,173 resulting contigs have been subjected to computational and physical quality assessments. Comparisons to the sequences of maize bacterial artificial chromosomes suggest that at least 97% (160 of 165) of MAGIs are correctly assembled. Because the rates at which junction-testing PCR primers for genomic survey sequences (90-92%) amplify genomic DNA are not significantly different from those of control primers ( approximately 91%), we conclude that a very high percentage of genic MAGIs accurately reflect the structure of the maize genome. EST alignments, ab initio gene prediction, and sequence similarity searches of the MAGIs are available at the Iowa State University MAGI web site. This assembly contains 46,688 ab initio predicted genes. The expression of almost half (628 of 1,369) of a sample of the predicted genes that lack expression evidence was validated by RT-PCR. Our analyses suggest that the maize genome contains between approximately 33,000 and approximately 54,000 expressed genes. Approximately 5% (32 of 628) of the maize transcripts discovered do not have detectable paralogs among maize ESTs or detectable homologs from other species in the GenBank NR nucleotide/protein database. Analyses therefore suggest that this assembly of the maize genome contains approximately 350 previously uncharacterized expressed genes. We hypothesize that these "orphans" evolved quickly during maize evolution and/or domestication.

Chromosomes, Artificial, Bacterial↗

Diploid genome assembly of human fibroblast cell lines enables clone specific variant calling, improved read mapping and accurate phasing.

Human cell lines are fundamental tools in biomedical research and are widely used in disease modeling, drug development, and many other domains. Here, we present chromosome-level, phased diploid genome assemblies of two popular human cell lines: the BJ foreskin fibroblast line and the IMR-90 fetal lung fibroblast line. Our high-quality assemblies, generated using long-read and Hi-C sequencing data, reveal substantial structural variation, including more than 50,000 insertions, deletions, duplications, and inversions compared to the recent T2T-CHM13v2.0 reference. Our assemblies provide detailed maps of genetic variation, enabling more accurate variant calling and the ability to phase reads when using newly generated or historical sequencing data on these cell lines or their derivatives. All assemblies and associated data have been made available as a resource for the research community. We envision that diploid genome assembly will become a cornerstone approach for personalized medicine in the near future.

Journal Article↗

VicMAG, an open-source tool for visualizing circular metagenome-assembled genomes highlighting bacterial virulence and antimicrobial resistance.

Bacterial pathogens spread in clinical and environmental settings, and mobile genetic elements (MGEs), such as plasmids and phages, mediate the transfer of virulence factor genes (VFGs) and antimicrobial resistance genes (ARGs) among bacterial communities. Metagenomic analysis of environmental and wastewater samples using highly accurate long-read sequencing technologies, such as Pacific Biosciences (PacBio) HiFi sequencing, provides valuable insights into monitoring the regional spread of VFGs and ARGs, including dissemination mediated by MGEs. No visualization tool is currently available for the comprehensive display of numerous resulting circular metagenome-assembled genomes (cMAGs) with functional gene annotations. Here, we developed visualization of circular metagenome-assembled genome (VicMAG), a visualization tool for highly complex cMAGs derived from long-read metagenome assemblies annotated using updated databases of VFGs, ARGs, and MGEs. Using 353 cMAGs from PacBio HiFi sequencing of a wastewater sample, we demonstrated the utility of VicMAG for metagenome visualization. VicMAG provides comprehensive, size-aware visualization of cMAGs representing bacterial chromosomes and plasmids, annotated with VFGs, ARGs, and phages. By simultaneously visualizing all cMAGs in a framework, VicMAG facilitates a holistic understanding of the distribution and genomic context of VFGs and ARGs across complex microbial communities. This tool supports integrated surveillance of bacteria associated with virulence and antimicrobial resistance across clinical, environmental, and One Health contexts.

Metagenome↗

Chromosome-level genome assembly and annotation of Pterygoplichthys pardalis.

Suckermouth catfishes, with their evolved powerful features, have become notorious invasive species, causing significant damage to aquatic ecosystems. However, the lack of high-quality genomes severely restricts research on this group within the field. In this study, we de novo assembled the chromosome-level genome assembly of Pterygoplichthys pardalis using multiple platforms of sequencing data, including Illumina short reads, Nanopore long reads, and Hi-C sequencing reads, resulting in a 1.51 Gb genome assembly. Multiple evaluations, including read mapping ratio (98.52%), transcript mapping ratio (99.61%), conserved BUSCO gene set (98.8%), and N50 score (49.47 Mb), indicated the high continuity and accuracy of the genome assembly we generated. Genome annotation found that 0.97 Gb of genome sequences are repetitive sequences, accounting for 64.47% of the genome assembly. Further, 23,859 protein-coding genes were successfully predicted, 92.92% of which could be annotated in functional databases. This high-quality genome assembly of P. pardalis provides a valuable resource for understanding the genetic underpinnings of P. pardalis's invasive success and offers critical data for future fisheries research and management.

Animals↗

The chromosome-level genome assembly of Prunus cerasifera 'Atropurpurea'.

Prunus cerasifera 'Atropurpurea' (Purpleleaf Plum), known for its unique purple-red foliage, is an important ornamental plant that enhances the aesthetic value of urban greening. To explore the molecular mechanisms underlying leaf color changes, this study assembled the Purpleleaf Plum genome, providing new insights for related research. We used HiFi sequencing data to assemble its genome. After chromosome anchoring, the final genome size was 244.89 Mb, with a contig N50 of 26.60 Mb, and approximately 97.10% of sequences were anchored to 8 chromosomes. Genome annotation identified 28,231 protein-coding genes, with LTR transposons comprising 27.93% of the genome. BUSCO assessment revealed a genome completeness of 98.9%. Telomeric repeat analysis identified 14 telomeres, with six chromosomes capped by double telomeres and two chromosomes containing a single telomere. This high-quality Purpleleaf Plum genome provides a solid foundation for future gene function analysis, cultivar improvement, and genetic research, offering valuable resources for related fields.

Genome, Plant↗

Chromosome-level genome assembly of starry flounder (Platichthys stellatus).

Starry flounder (Platichthys stellatus) is widely distributed along the coastlines of the North Pacific. As an euryhaline flatfish, it can adapt to a wide range of environmental salinity ranging from freshwater to seawater, and is a promising aquaculture flatfish species in Korea and North China. However, no high-quality starry flounder reference genome has been reported to date, which greatly limits the studies of genetics and functional genomics. Here, we obtained a high-quality chromosome-level starry flounder genome assembly with a length of 643.56 Mb (scaffold N50: 26.19 Mb, contig N50: 10.00 Mb) combining short-reads sequencing, PacBio HiFi sequencing, and Hi-C sequencing. Approximately 94.02% of assembled sequences were anchored into 24 pseudochromosomes, and a total of 18 telomeres were detected. Totally 22,835 protein-coding genes and 227.87 Mb repetitive sequences were identified. In summary, the high-quality chromosome-level genome assembly not only provides valuable resources for genetic research in starry flounder, but also advances the development of molecular breeding technology of starry flounder.

Animals↗

A whole-genome assembly of Drosophila.

We report on the quality of a whole-genome assembly of Drosophila melanogaster and the nature of the computer algorithms that accomplished it. Three independent external data sources essentially agree with and support the assembly's sequence and ordering of contigs across the euchromatic portion of the genome. In addition, there are isolated contigs that we believe represent nonrepetitive pockets within the heterochromatin of the centromeres. Comparison with a previously sequenced 2.9- megabase region indicates that sequencing accuracy within nonrepetitive segments is greater than 99. 99% without manual curation. As such, this initial reconstruction of the Drosophila sequence should be of substantial value to the scientific community.

Algorithms↗

High quality genome assemblies of African cattle breeds using PacBio HiFi sequencing.

Africa has a uniquely rich cattle diversity of ~150 breeds comprising the Bos taurus indicus sub-species, Bos taurus taurus, and their crosses. These represent ~23% of the global cattle population. However, high quality, representative assemblies are limited for African cattle and especially for indicine breeds. Here we built high quality de novo assemblies for five important African indigenous cattle breeds using PacBio HiFi sequencing: Lagune (Bos taurus taurus), Gudali, Iringa Red and Singida White (Bos taurus indicus), and Mpwapwa (Bos taurus taurus x Bos taurus indicus). These new assemblies are the most contiguous and complete African cattle assemblies produced so far, with genome sizes of 3.25-3.36 Gb, contiguity N50s ranging from 83.59 Mb to 97.87 Mb and scaffold N50s from 100.30 Mb to 113.37 Mb. BUSCO genome completeness scores were also higher than 99.68%, indicative of highly contiguous assemblies. These improved and highly contiguous genome assemblies are consequently a valuable resource for future African and global livestock genomic studies.

Animals↗

De novo genome assembly of Clonostachys rosea CMAA1284: a fungal strain with biotechnological potential.

Clonostachys rosea is a fungus with significant applications in biological control, plant growth promotion, and secondary metabolite production essential for agriculture. We report the de novo genome assembly of C. rosea strain CMAA1284 (also known as LQC 62), which shows high contiguity and excellent gene completeness, supporting its use for functional genomics and biotechnological studies.

Clonostachys rosea↗

Assembling genomes of non-model plants: A case study with evolutionary insights from Ranunculus (Ranunculaceae).

Whereas genome sequencing and assembly technologies are improving, cost can still be prohibitive for plant species with large, complex genomes. As a consequence, genomics work on some taxa in evolutionarily pivotal positions in the vascular plant tree of life has been hampered. The species-rich genus Ranunculus (Ranunculaceae) is an important angiosperm group for the study of polyploidy, apomixis, and reticulate evolution. However, neither mitochondrial nor high-quality nuclear genome sequences are available. This limits phylogenomic, functional, and taxonomic analyses thus far. Here, we tested Illumina short-read, Oxford Nanopore Technology (ONT) and PacBio (HiFi) long-read, and hybrid-read assembly strategies. We sequenced the diploid progenitor species R. cassubicifolius (R. auricomus species complex) and selected the best assemblies in terms of completeness, contiguity, and quality scores. We first assembled the plastome (156 kbp, 85 genes) and mitogenome (1.18 Mbp, 40 genes) sequences using Illumina and Illumina-PacBio-hybrid strategies, respectively. We also present an updated plastome and the first mitogenome phylogeny of Ranunculaceae, including studies of gene loss (e.g., infA, ycf15, or rps) with evolutionary implications. For the nuclear genome sequence, we favored a PacBio-based assembly polished three times with filtered short reads and subsequently scaffolded into eight pseudochromosomes by chromatin conformation data (Hi-C). We obtained a haploid genome sequence of 2.69 Gbp, with 94.1% complete BUSCO genes found and 35 482 annotated genes, and inferred ancient gene duplications compared to existing Ranunculales genomes. The genomic information presented here will enable advanced evolutionary-functional analyses for the species complex, but also for the genus and beyond Ranunculaceae.

Ranunculus↗

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↗

Chromosome-level genome assembly of bivalve mollusk, Xishishe Coelomactra antiquata.

Coelomactra antiquata, a significant marine economic shellfish in China, is experiencing a natural population decline due to habitat destruction and overfishing, making the restoration and conservation of its natural resources an urgent priority. This study provides a high - quality chromosome - level genome assembly for C. antiquata, created by PacBio and Hi - C sequencing and resulting in a 19 - chromosome map. The assembly encompasses a genome size of 807.31 Mb, with a contig N50 of 17.35 Mb and a scaffold N50 of 42.90 Mb. A total of 28,070 protein - coding genes were identified, 25,959 of which were functionally annotated. Overall, this study offers a chromosome - level genome for C. antiquata that is highly continuous and complete, providing an indispensable resource for subsequent molecular and genetic studies of this species.

Animals↗

Genome assembly of Astatotilapia latifasciata uncovers B chromosome-linked chromatin reorganization.

B chromosomes (Bs) are supernumerary genomic elements found in many eukaryotes, yet their full sequence composition, functional potential, and regulatory impact on the host genome remain unclear. Here, we present a chromosome-level genome assembly of the cichlid fish Astatotilapia latifasciata, integrating PacBio long reads, Illumina short reads, and Hi-C chromatin contact maps to resolve both A and B chromosomes. The 0.93 Gb assembly (N50 = 36.2 Mb) includes a 34 Mb B chromosome containing 789 predicted protein-coding genes and a markedly higher density of transposable elements (TEs), especially long terminal repeats (LTR) retrotransposons. Transcriptome profiling revealed that B-linked genes are predominantly transcriptionally repressed relative to their A chromosome paralogs. Hi-C-based chromatin modeling uncovered distinct 3D structural configurations associated with the B chromosome, including fewer topologically associating domains (TADs), reduced loop formation, and altered compartmentalization. These changes are linked to long-range chromatin interactions and genomic rearrangements, suggesting that the B chromosome reshapes the nuclear architecture of the host genome. Our study proposes a potential regulatory role of Bs in genome and provides a genomic resource for investigating chromosome evolution in cichlids.

Animals↗