Genome Research Articles

The genome sequence of a seed weevil, Aspidapion aeneum (Fabricius, 1775)

We present a genome assembly from a specimen of Aspidapion aeneum (seed weevil; Arthropoda; Insecta; Coleoptera; Apionidae). The genome sequence has a total length of 1,286.20 megabases. Most of the assembly (98.78%) is scaffolded into 11 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 21.49 kilobases in length.

The genome sequence of the Sandy Carpet moth, Perizoma flavofasciatum (Thunberg, 1792)

We present a genome assembly from a male specimen of Perizoma flavofasciatum (Sandy Carpet; Arthropoda; Insecta; Lepidoptera; Geometridae). The genome sequence has a total length of 369.30 megabases. Most of the assembly (99.88%) is scaffolded into 30 chromosomal pseudomolecules, including the Z sex chromosome. The mitochondrial genome has also been assembled and is 16.61 kilobases in length. Gene annotation of this assembly on Ensembl identified 11,915 protein-coding genes.

The genome sequence of the common marigold, Calendula officinalis L.

We present a genome assembly from an individual Calendula officinalis (the common marigold; Streptophyta; Magnoliopsida; Asterales; Asteraceae). The genome sequence has a total length of 1,215.20 megabases. Most of the 1n assembly is scaffolded into 16 chromosomal pseudomolecules, suggesting the individual is an allotetraploid (2n = 4x = 32). The mitochondrial assemblies are 225.50 and 127.82 kilobases in length and the plastid genome assembly is150.47 kilobases long. Gene annotation of this assembly on Ensembl identified 58,402 protein-coding genes.

Double carbapenemases in Klebsiella pneumoniae blood isolates: dissemination in a single medical center via multiple plasmids and a variety of highly efficient clones.

Acquisition of multiple carbapenemase genes by Klebsiella pneumoniae (Kp) is an emerging public health threat. Here, we aim to elucidate the population structure of Kp blood isolates carrying two different carbapenemase genes and identify the mechanism facilitating their dissemination. The study was conducted in a tertiary healthcare center between 2014 and 2022. Twenty-four patients with bacteremia caused by Kp carrying two different carbapenemase genes were identified. All 24 blood isolates were analyzed by short-read genome sequences supplemented by long reads in a selected number of isolates. All isolates carried blaKPC (23 blaKPC-2, 1 blaKPC-3) and blaVIM-1 genes, along with a variety of antimicrobial resistance determinants. The isolates were clustered in six clonal lineages (ST39, ST147, ST323, ST258, ST3035, and ST340). Long-read genome sequences demonstrated that each carbapenemase gene was located in a separate group of plasmids: the blaKPC-2 on a fusion of IncFIB(pQil) and IncFII(K) plasmids, the blaKPC-3 on IncX3, the blaVIM-1 on IncC, or a fusion of the IncFIB(pNDM-Mar) and IncHI1B(pNDM-MAR) plasmids. Comparison of plasmid content of eight isolates carrying a single carbapenemase gene from a previous study with eight isolates carrying two carbapenemase genes from the present study, matched by clonal lineages, revealed that the second carbapenemase gene was acquired by addition of another plasmid. Identical plasmids were found within the same lineage and across lineages. These findings suggest that dissemination of carbapenemase genes in our hospital setting was driven by multiple plasmids across a variety of highly efficient clones.

The genome sequence of the Lesser Sea-spurrey, Spergularia marina (L.) Besser

We present a genome assembly from a specimen of Spergularia marina (Lesser Sea-spurrey; Streptophyta; Magnoliopsida; Caryophyllales; Caryophyllaceae). The genome sequence has a total length of 499.30 megabases. Most of the assembly is scaffolded into 18 chromosomal pseudomolecules, suggesting the individual is an allotetraploid (2n = 4x = 36). The mitochondrial and plastid genome assemblies have lengths of 327.07 kilobases and 152.28 kilobases, respectively. Gene annotation of this assembly on Ensembl identified 37,641 protein-coding genes.

The genome sequence of the Pacific oyster, Magallana gigas (Thunberg, 1793)

We present a genome assembly from an individual Magallana gigas (the Pacific oyster; Mollusca; Bivalvia; Ostreida; Ostreidae). The genome sequence is 564.0 megabases in span. Most of the assembly is scaffolded into 10 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 18.23 kilobases in length. Gene annotation of this assembly on Ensembl identified 19,775 protein-coding genes.

The genome sequence of a cluster fly, Pollenia griseotomentosa (Jacentkovský, 1944)

We present a genome assembly from an individual Pollenia griseotomentosa (cluster fly; Arthropoda; Insecta; Diptera; Polleniidae). The genome sequence has a total length of 1,046.30 megabases. Most of the assembly (99.57%) is scaffolded into 6 chromosomal pseudomolecules, including the X sex chromosome. The mitochondrial genome has also been assembled and is 17.23 kilobases in length.

A CACTA-like transposon in the Anthocyanidin synthase 1 (Ans-1) gene is responsible for apricot fruit colour in the raspberry (Rubus idaeus) cultivar 'Varnes'.

Cultivated raspberries (Rubus idaeus L.) most commonly bear small, red, highly aromatic fruits. Their colour is derived predominantly from anthocyanins, water soluble polyphenolic pigments, but as well as red forms, there exist cultivars that display yellow- and apricot-coloured fruits. In this investigation, we used a multi-omics approach to elucidate the genetic basis of the apricot fruit colour in raspberry. Using metabolomics, we quantified anthocyanins in red and apricot raspberry fruits and demonstrated that, in contrast to red-fruited raspberries, fruits of the apricot cultivar 'Varnes' contain low concentrations of only a small number of anthocyanin compounds. By performing RNASeq, we revealed differential expression patterns in the apricot-fruited 'Varnes' for genes in the anthocyanin biosynthesis pathway and following whole genome sequencing using long-read Oxford Nanopore Technologies sequencing, we identified a CACTA-like transposable element (TE) in the second exon of the Anthocyanidin synthase (Ans) gene that caused a truncated predicted ANS protein. PCR confirmed the presence in heterozygous form of the transposon in an unrelated, red-fruited cultivar 'Veten', indicating apricot fruit colour is recessive to red and that it may be widespread in raspberry germplasm, potentially explaining why apricot forms appear at regular intervals in modern raspberry breeding populations.

The genome sequence of the Grey Arches moth, Polia nebulosa Hufnagel, 1766

We present a genome assembly from an individual male specimen of Polia nebulosa (Grey Arches; Arthropoda; Insecta; Lepidoptera; Noctuidae). The genome sequence has a total length of 1,011.20 megabases. Most of the primary assembly (99.27%) is scaffolded into 30 chromosomal pseudomolecules, including the Z sex chromosome. The mitochondrial genome has also been assembled and is 15.39 kilobases in length.

Convergent Evolution and Predictability of Gene Copy Numbers Associated with Diets in Mammals.

Convergent evolution, the evolution of the same or similar phenotypes in phylogenetically independent lineages, is a widespread phenomenon in nature. If the genetic basis for convergent evolution is predictable to some extent, it may be possible to infer organismic phenotypes and the capability of organisms to utilize new ecological resources based on genome sequence data. While repeated amino acid changes have been studied in association with convergent evolution, relatively little is known about the potential contribution of repeated gene copy number changes. In this study, we explore whether gene copy number changes of particular gene families are linked to diet shifts in mammals and assess whether trophic ecology can be inferred from the copy numbers of a specific set of gene families. Using 86 mammalian genome sequences, we identified 24 gene families with a trend toward higher copy numbers in herbivores, carnivores, and omnivores, even after phylogenetic corrections. We were able to confirm previous findings on genes such as amylase, olfactory receptors, and xenobiotic metabolism genes, and identify novel gene families whose copy numbers correlate with dietary patterns. For example, omnivores exhibited higher copy numbers of genes encoding regulators of translation. We also established a discriminant function based on the copy numbers of 13 gene families that can help predict trophic ecology to some extent. These findings highlight a possible association between convergent evolution and repeated copy number changes in specific gene families, suggesting the potential to develop a method for predicting animal ecology from genome sequence data.

Enhancing diagnostic outcomes in kidney genetic disorders: the KidGen national kidney genomics study protocol

BackgroundGenetic kidney disease (GKD) significantly affects the community and is responsible for a notable portion of adult kidney disease cases and about half of cases in paediatric patients. It substantially impacts the quality of life and life expectancy for affected children and adults across all stages of kidney disease. Precise genetic diagnosis in GKD promises to improve patient outcomes, provide access to targeted treatments, and reduce the disease burden for individuals, families, and healthcare systems. Genetic investigations are increasingly used in nephrology practice; however, many patients who undergo testing still lack a definitive diagnosis.MethodsThe KidGen National Kidney Genomics Study aims to increase diagnostic yield for those with suspected monogenic kidney disease without a diagnosis after standard diagnostic genetic testing. The program will seek to enrol up to 200 families from KidGen Collaborative kidney genetics clinics across Australia who have yet to receive conclusive diagnoses despite prior testing. Participants will undergo a personalised pathway of research genomic investigations. These include re-analysing existing data and/or undergoing advanced genomic testing methods, including short and long-read whole-genome sequencing, RNA sequencing, and functional genomics strategies using mouse modelling or kidney organoids.DiscussionThe KidGen National Kidney Genomics Study is a coordinated, multidisciplinary extension of previous research projects that aims to assess the diagnostic yield of advanced genomic approaches. The study's evidence will drive changes to current diagnostic pathways, including identifying which chronic kidney disease patients are most likely to benefit from a more comprehensive genomic approach to diagnosis.

Population Genomics of Premature Termination Codons in Cavefish With Substantial Trait Loss.

Loss-of-function alleles are a pertinent source of genetic variation with the potential to contribute to adaptation. Cave-adapted organisms exhibit striking loss of ancestral traits such as eyes and pigment, suggesting that loss-of-function alleles may play an outsized role in these systems. Here, we leverage 141 whole genome sequences to evaluate the evolutionary history and adaptive potential of single nucleotide premature termination codons (PTCs) in Mexican tetra. We find that cave populations contain significantly more PTCs at high frequency than surface populations. We also find that PTCs occur more frequently in genes with inherent relaxed evolutionary constraint relative to the rest of the genome. Using SLiM to simulate PTC evolution in a cavefish population, we show that the smaller population size and increased genetic drift is sufficient to account for the observed increase in PTC frequency in cave populations without positive selection. Using CRISPR-Cas9, we show that mutation of one of these genes, pde6c, produces phenotypes in surface Mexican tetra that mimic cave-derived traits. Finally, we identify a small subset of candidate genes that contain high-frequency PTCs in cave populations, occur within selective sweeps, and may contribute to beneficial traits such as reduced energy expenditure, suggesting that a handful of PTCs may be adaptive. Overall, our work provides a rare characterization of PTCs across wild populations and finds that they may have an important role in loss-of-function phenotypes, contributing to a growing body of literature showing genome evolution through relaxed constraint in subterranean organisms.

Comparative gametogenesis and genomic signatures associated with pollen sterility in the seedless mutant of grapevine

BackgroundSeedless grapes are in high demand for fresh and dry fruit consumption. Seedlessness in grapes (Vitis vinifera L.) is triggered by two different mechanisms: stenospermocarpy and parthenocarpy. However, the key regulators of seed development and their targets in grapes are not well characterized. The present study used the seeded grape hybrid ARI 516 and its seedless mutant to understand the molecular mechanisms controlling the seedless phenotype in grapes.ResultsGametogenesis studies demonstrated that the seedless mutant exhibits pollen sterility due to abnormal pollen morphology, significantly low viability, and a complete lack of germination ability. The macrogametophyte in the seedless mutant was significantly smaller than in ARI 516. Transcriptomic comparisons were performed during three developmental stages, including pre-flowering stage E-L 15, anthesis stage E-L 23, and berry formation E-L 31, to study altered developmental processes in the seedless mutant and ARI 516. Genes downregulated in the seedless mutant were enriched in the male gametophyte development-related pathways, which may cause pollen sterility. The RNAseq results were validated by qRT-PCR. Genome sequence data was also used to identify induced mutations in the seedless mutant, which revealed three homozygous and 25 heterozygous InDels in the genes related to male gametophyte development. RNAseq and genome sequencing data collectively indicate parthenocarpic seedless phenotype due to aberrant developmental and physiological processes involved in pollen formation, maturation and germination in the seedless mutant of ARI 516.ConclusionThe study showed the downregulation of transcription factors and their target genes involved in cell division, gibberellin biosynthesis and signalling, cell wall development, organization, and pollen germination. This study represents a comprehensive attempt to identify putative candidate genes associated with parthenocarpic pollen sterility in grapes using genomic approaches.

Complete genome sequences of AZ Arthrobacter phages Wildwest and Sue2.

This announcement reports the complete genome sequences of two bacteriophages isolated from soil samples using the host Arthrobacter atrocyaneus Strain NRRL B-2883. These findings enhance our understanding of AZ1 cluster phages, particularly Wildwest and Sue2, with their unique genomic features.

What do we gain when tolerating loss? The information bottleneck wrings out recombination.

Most microbes have the capacity to acquire genetic material from their environment. Recombination of foreign DNA yields genomes that are, at least in part, incongruent with the vertical history of their species. Dominant approaches for detecting these transfers are phylogenetic, requiring a painstaking series of analyses including alignment and tree reconstruction. But these methods do not scale. Here we propose an unsupervised, alignment-free and tree-free technique based on the sequential information bottleneck (SIB), an optimization procedure designed to extract some portion of relevant information from one random variable conditioned on another. In our case, this joint probability distribution tabulates occurrence counts of k-mers against their genomes of origin with the expectation that recombination will create a strong signal that unifies certain sets of co-occuring k-mers. We conceptualize the technique as a rate-distortion problem, measuring distortion in the relevance information as k-mers are compressed into clusters based on their co-occurrence in the source genomes. The result is fast, model-free, lossy compression of k-mers into learned groups of shared genome sequence, differentiating recombined elements from the vertically inherited core. We show that the technique yields a new recombination measure based purely on information, divorced from any biases and limitations inherent to alignment and phylogeny.

Coding-complete genome sequence of a bovine viral diarrhea virus subgenotype 1v strain isolated in China.

We sequenced the coding-complete genome sequence of bovine viral diarrhea virus (BVDV) strain NX2019/02. It belongs to the 1v subgenotype. This report will increase our understanding of the epidemiology of BVDV in China.

Tersicoccus mangrovi sp. nov., a novel actinobacterium from mangrove sediment in Semarang city, Indonesia.

A Gram-stain-positive, aerobic and non-motile actinobacterium, designated strain MR15.9T, was isolated from sediment collected from a mangrove ecosystem in Semarang city, Indonesia. Strain MR15.9T grew at 4-37 °C (optimum 30 °C), pH 6.0-11.0 (optimum 7.0-8.0), with 0-10% (w/v) NaCl (optimum 0-3%). The genome of strain MR15.9T was 3.67 Mbp with 71.7 mol% G+C content. Phylogenetic analysis based on 16S rRNA gene sequence and genome sequence directed that strain MR15.9T formed a well-supported clade with Tersicoccus solisilvae CGMCC 1.15480T and Tersicoccus phoenicis 1P05MAT and shared the highest similarity to T. solisilvae CGMCC 1.15480T (98.9% sequence similarity) and T. phoenicis 1P05MAT (98.6% sequence similarity). However, the comparative genome analysis between strain MR15.9T and T. solisilvae CGMCC 1.15480T gave average nt identity value of 85.2% and digital DNA-DNA hybridization value of 29.0%, which were below the statistical threshold for the delineation of the species. Chemotaxonomic data showed that the major fatty acids were anteiso-C15:0, anteiso-C17:0 and iso-C16:0. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two unidentified glycolipids and two unidentified phospholipids. MK-8(H2) and MK-9(H2) were noted as the predominant respiratory quinones in this strain. The results of polyphasic characterization indicated that strain MR15.9T represents a novel species of the genus Tersicoccus. The name Tersicoccus mangrovi sp. nov. is proposed, with the type strain MR15.9T (=MCCC 1K08875T=KCTC 59105T).

The additional diagnostic yield of long-read sequencing in undiagnosed rare diseases

Long-read sequencing (LRS) is a promising technology positioned to study the significant proportion of rare diseases (RDs) that remain undiagnosed as it addresses many of the limitations of short-read sequencing, detecting and clarifying additional disease-associated variants that may be missed by the current standard diagnostic workflow for RDs. Some key areas where additional diagnostic yields may be realized include: (1) detection and resolution of structural variants (SVs); (2) detection and characterization of tandem repeat expansions; (3) coverage of regions of high sequence similarity; (4) variant phasing; (5) the use of de novo genome assemblies for reference-based or graph genome variant detection; and (6) epigenetic and transcriptomic evaluations. Examples from over 50 studies support that the main areas of added diagnostic yield currently lie in SV detection and characterization, repeat expansion assessment, and phasing (with or without DNA methylation information). Several emerging studies applying LRS in cohorts of undiagnosed RDs also demonstrate that LRS can boost diagnostic yields following negative standard-of-care clinical testing and provide an added yield of 7%–17% following negative short-read genome sequencing. With this evidence of improved diagnostic yield, we discuss the incorporation of LRS into the diagnostic care pathway for undiagnosed RDs, including current challenges and considerations, with the ultimate goal of ending the diagnostic odyssey for countless individuals with RDs.

Pathogenicity of avian reovirus variant in the immune organs of broiler chicks.

In recent years, the infection rate of avian reovirus (ARV) in chicks has been continuously increasing, seriously endangering the healthy development of China's chicken farming industry. However, the pathogenicity of this virus in immune organs has been less studied. In this study, an ARV strain (Chicken/XJ/China/2022/01/16) was isolated from arthritic broiler chicks in Xinjiang province and whole genome sequencing of the ARV strain was performed using next generation sequencing (NGS) technology, and sequence analysis showed that the strain was a type V variant of the ARV gene. In order to further understand the pathogenicity of this strain in terms of immune organs, we randomized 120 healthy 1-day-old broilers equally into 3 groups (oral, footpad inoculation and control), where 2 experimental groups were inoculated with 0.2 mL of ARV (TCID50 of 105.5 /0.1 mL) and the control group was inoculated with an equal amount of sterile saline. The results showed that the footpad inoculation group showed more severe symptoms, which, in addition to causing chick dwarf syndrome and viral arthritis, would also cause serious effects on the immune organs of the chicks. Among them, the spleen and bursa were most seriously damaged, the symptoms of arthritis appeared relatively late, which indicated that the spleen and bursa might be the main target organs preferentially attacked by avian reovirus. This study provides a rationale for the prevention and control of emerging avian reovirus and adds to the evidence of the effects of ARV on immune organs, with the expectation that it will be useful in understanding the immune response-related aspects of the disease in subsequent studies.

A novel virulent core genome multilocus sequence type CT 11424 of Listeria monocytogenes isolate causing stillbirth in Bangladesh

BackgroundListeria monocytogenes is a foodborne pathogen that can lead to severe pregnancy outcomes. This study reports the clinical and genomic characteristics of a Listeria-mediated stillbirth identified in January 2022 through the Child Health and Mortality Prevention Surveillance (CHAMPS) project in Bangladesh. The Lm-BD-CHAMPS-01 isolate was recovered from the blood and cerebrospinal fluid (CSF) of a male stillborn. Maternal history, clinical, and demographic data were collected by the CHAMPS surveillance platform. An expert panel evaluated all reports to determine the role of L. monocytogenes infection in the causal chain of stillbirth. Genomic characterization included multilocus sequence typing (MLST), core genome MLST (cgMLST), serotyping, and the presence or absence of virulence genes. Genetic divergence and phylogenetic analyses were conducted to determine the relationship with other reported isolates globally.ResultsThe isolate Lm-BD-CHAMPS-01 was identified as a novel cgMLST CT11424. It belonged to ST 308, Serotype 4b, Clonal Complex 1, and Phylogenetic Lineage 1. Key L. monocytogenes virulence genes facilitating the crossing of the placental barrier, including full-length inlA, LIPI-1, and LIPI-3, were detected. The isolate was closely related to clinical L. monocytogenes isolates, as determined by GrapeTree based on cgMLST. SNP-based phylogenetic analysis found Lm-BD-CHAMPS-01 to be the most distant from other CC1 isolates in the database. Possible sources of infection included the consumption of contaminated raw vegetables or exposure to pigeons.ConclusionsThis is the first genome sequence of clinical L. monocytogenes from Bangladesh, which also caused stillbirth. Rural healthcare professionals should be aware of L. monocytogenes infection risks during pregnancy. Pregnant women should be counseled on the dangers of exposure to animals or birds and consumption of potentially contaminated raw food to prevent adverse pregnancy outcomes due to L. monocytogenes infection.