Phylogenetic tree building in the genomic age

Threshold sensitivity analysis for HIV-1 transmission cluster detection using different genomic regions and subtypes

HIV-1 cluster analysis has been widely used in characterizing HIV-1 transmission and some countries have implemented such molecular epidemiology as part of their prevention strategy. However, HIV-1 sequences derive from varying genome regions, which affects phylogenetic clustering outputs. Here, we apply different tools to run a sensitivity analysis for assessing which threshold give the most cohesive clustering outputs for different data sources. We used a dataset of 174 full-length sequences of subtype B from the Swiss HIV Cohort Study and publicly available subtype C from South Africa. Each dataset was divided into sub-genomic sub-datasets covering gag, pol, and env. pol was further subdivided into regions commonly used in HIV-1 genotyping laboratories (pr-rt, rt-int, and pr-rt-int). Cluster analyses for each sub-genomic region was performed specifying varying distance thresholds of 0.5 %-4.5 % and tree branch support of 70 %, 90 % and 99 % in ClusterPicker. Tree topologies and clustering outputs were compared against each other to assess cluster similarity. Pylogenies using pol, pr-rt-int, or rt-int had more robust tree topologies compared to gag and env. Cluster composition changed with increasing genetic distance threshold but was not affected by branch support. Cluster identity was most similar around genetic distances of 2.5 (±0.5)% for all sub-genomic regions and for both subtype B and C. Our study demonstrated the value of performing a sensitivity analysis before setting a genetic distance threshold for clustering output and that the pol region is appropriate for clustering outputs and can be used for near real-time HIV-1 cluster detection.

Accurate, scalable, and fully automated inference of species trees from raw genome assemblies using ROADIES

Current genome sequencing initiatives across a wide range of life forms offer significant potential to enhance our understanding of evolutionary relationships and support transformative biological and medical applications. Species trees play a central role in many of these applications; however, despite the widespread availability of genome assemblies, accurate inference of species trees remains challenging due to the limited automation, substantial domain expertise, and computational resources required by conventional methods. To address this limitation, we present ROADIES, a fully automated pipeline to infer species trees starting from raw genome assemblies. In contrast to the prominent approach, ROADIES incorporates a unique strategy of randomly sampling segments of the input genomes to generate gene trees. This eliminates the need for predefining a set of loci, limiting the analyses to a fixed number of genes, and performing the cumbersome gene annotation and/or whole genome alignment steps. ROADIES also eliminates the need to infer orthology by leveraging existing discordance-aware methods that allow multicopy genes. Using the genomic datasets from large-scale sequencing efforts across four diverse life forms (placental mammals, pomace flies, birds, and budding yeasts), we show that ROADIES infers species trees that are comparable in quality to the state-of-the-art studies but in a fraction of the time and effort, including on challenging datasets with rampant gene tree discordance and complex polyploidy. With its speed, accuracy, and automation, ROADIES has the potential to vastly simplify species tree inference, making it accessible to a broader range of scientists and applications.

A Jurassic acanthocephalan illuminates the origin of thorny-headed worms

Acanthocephala (thorny-headed worms), characterized by the presence of an eversible proboscis with hooks, are a diverse endoparasitic group that infect a wide range of vertebrates and invertebrates1. Although long regarded as a separate phylum, they have several putative sister taxa based on morphological features, including Platyhelminthes (flatworms)2, Priapulida (penis worms)3 and Rotifera (wheel animals)4. Molecular phylogenies have instead recovered them within rotifers5-10, suggesting acanthocephalans are derived from free-living worms with a jaw apparatus (Gnathifera). Their only fossil record is Late Cretaceous eggs11, contributing limited palaeontological information to deciphering their early evolution. Here we describe an acanthocephalan body fossil, Juracanthocephalus daohugouensis gen. et. sp. nov., from the Middle Jurassic Daohugou biota of China. Juracanthocephalus shows unambiguous acanthocephalan characteristics, for example a hooked proboscis, a bursa, as well as a jaw apparatus with discrete elements that is typical of other gnathiferans. Juracanthocephalus shares features with Seisonidea (an epizoic member of Rotifera) and Acanthocephala, bridging the evolutionary gap between jawed rotifers and the obligate parasitic, jawless acanthocephalans. Our results reveal previously unrecognized ecological and morphological diversity in ancient Acanthocephala and highlight the significance of transitional fossils, revealing the origins of this highly enigmatic group of living organisms.

Exploring Mitonuclear Discordance: Ghost Introgression From an Ancient Extinction Lineage in the Odorrana swinhoana Complex

Mitonuclear discordance, the incongruence between mitochondrial DNA (mtDNA) and nuclear DNA (nuDNA), is a well-documented phenomenon with various potential explanations. One emerging hypothesis, ghost introgression, refers to the genetic contribution of an ancient, extinct or unsampled lineage and can now be tested using modern genomic data and demographic models. In this study, we investigated the evolutionary history of the Odorrana swinhoana complex (Anura: Ranidae), which includes O. swinhoana, O. utsunomiyaorum and an unidentified population with highly divergent mtDNA. While mitochondrial phylogeny suggested this population as a basal lineage, nuclear data from ddRADseq revealed it as a mixture of the most derived O. swinhoana nuclear sequences combined with ancient mtDNA. Demographic modelling further supported ghost introgression, as all models incorporating a ghost population outperformed those without it. These findings suggest that an eastward expansion of western O. swinhoana replaced an ancient Odorrana lineage, leaving only its mtDNA and fragments of its nuclear genome in the hybrid population. Our results provide one of the first documented cases of ghost introgression in amphibians and highlight its potential as a widespread evolutionary process. This study also underscores the risks of relying solely on mtDNA for phylogenetic reconstruction and species delimitation.

Two new species of Penicillium (Eurotiales, Aspergillaceae) from China based on morphological and molecular analyses

Penicillium is a large and significant genus of fungi, exhibiting widespread distribution across diverse substrates. Ongoing taxonomic and nomenclatural revisions have led to an annual increase in the number of newly described species. This study described two new Penicillium species, i.e., P.lentum and P.tibetense, discovered in China. They have been identified and characterized through morphological examination and both single gene and multigene phylogenetic analyses. Based on these analyses, P.lentum was classified within the section Brevicompacta, while P.tibetense was placed in the section Lanata-Divaricata. Both species exhibited the morphological features typical of their respective sections. Penicilliumlentum is characterized by restricted growth with dense colonies on agar media and predominantly generates terverticillate conidiophores. Penicilliumtibetense demonstrates rapid growth on media and has vigorous growth on CYA at 30 °C, producing biverticillate conidiophores. Comprehensive descriptions and detailed illustrations of these new species were presented. A morphological comparison between the new species and their closely related taxa was provided.

Investigation of multi-drug resistant Candida auris using species-specific molecular markers in immunocompromised patients from a tertiary care hospital in Quetta, Pakistan

INTRODUCTION

Candida auris is an emerging multidrug-resistant pathogen responsible for nosocomial infections worldwide, characterized by high mortality rates and significant challenges in detection due to frequent misidentification. Classified by the WHO as a pathogen of critical importance since it exhibits resistance to multiple antifungal agents, particularly fluconazole, and is highly transmissible in healthcare settings. Conventional detection methods often lack the accuracy required for effective infection control. This study aimed to conduct inferential and molecular analyses of C. auris and other yeast species infecting immunocompromised patients in the Special and Intensive Care Units (SCU and ICU) of a tertiary care hospital in Quetta, Pakistan. In this region, C. auris remains rarely studied and is frequently misdiagnosed by clinical staff due to limited awareness and diagnostic challenges. Notably, no prior research has been conducted on C. auris in Quetta. The study also sought to develop reliable diagnostic methods suitable for resource-limited settings, addressing a critical gap in healthcare infrastructure.

MATERIALS AND METHODS

Samples (150 each) from the ear, axilla, groin, and saliva of SCU/ICU patients were collected and processed on yeast malt agar, with preliminary identification using Brilliance Candida Agar (BCA) and CHROMagar Candida Plus (CCP). Advanced techniques, including PCR amplification of ITS regions, DNA sequencing, RFLP with Msp1, MALDI-TOF, Vitek 2, and species-specific primers, were used for identification. Antifungal susceptibility to fluconazole, amphotericin B, and voriconazole were also assessed.

RESULTS

The culture test revealed that 42.6% samples were positive for yeast infections. In addition to detecting Candida auris in 4 cultures, chromogenic media identified 6 other Candida species: C. albicans, C. dubliniensis, C. glabrata, C. krusei, C. parapsilosis, and C. tropicalis. Further validation through advanced techniques, including molecular diagnostics and MALDI-TOF, enabled the identification of additional species: C. famata, C. kefyr, C. lusitaniae, and Meyerozyma (Candida) guilliermondii. Out of all identified yeast species C. dubliniensis was the most common, followed by C. albicans and C. tropicalis, with the highest infection rates observed in saliva samples. Antifungal Susceptibility Tests (AST) revealed that C. auris isolates were resistant to Fluconazole, Amphotericin B, and Voriconazole, highlighting multidrug resistance. This study represents the first report of novel multidrug-resistant C. auris from Quetta, Pakistan, indicating that C. auris is prevalent among ICU and SCU patients. Novel species specific primers targeting phospholipase B, topoisomerase II, CDR and 18s genes were designed in our laboratory and not previously reported in earlier studies, proved highly effective for the rapid identification of Candida species. The established protocol using these primers is recommended for implementation in resource-limited laboratory settings. The statistical analysis demonstrated significant correlations between Candida species infection (dependent variable) and several independent factors (variables) emphasizing the importance of targeted diagnostics and intervention strategies.

Gracilibacillus pellucidus sp. nov., a moderately halophilic bacterium isolated from saline soil in Xinjiang province, China

A motile, Gram-positive, moderately halophilic, catalase-positive and oxidase-negative, obligate aerobic, slender rod-shaped bacterium, strain S3-1-1T was isolated from the plant rhizosphere soil in saline soil of Xinjiang Uygur Autonomous Region. Strain S3-1-1T grew in the presence of 1-21% NaCl and at pH 7.0-9.0, with optimum growth at 3% NaCl and pH 7.5. It grew at 16-45 °C, with optimum growth at 40 °C.Phylogenetic analysis based on 16S rRNA gene sequences showed that strain S3-1-1T should be placed within the genus Gracilibacillus and formed a separate branch. It exhibited highest similarities to Gracilibacillus ureilyticus MF38T (sequence similarity 97.7%), Gracilibacillus massiliensis Awa-1T (sequence similarity 97.5%), Gracilibacillus xinjiangensis J2T (sequence similarity 97.4%) and Gracilibacillus salitolerans SCU50T (sequence similarity 97.4%). Genomic comparisons revealed that strain S3-1-1T shares closest phylogenetic relationships with Gracilibacillus saliphilus YIM 91119T (ANI 77.4%, AAI 78.4%), Gracilibacillus thailandensis TP2-8T (ANI 77.2%, AAI 78.3%), and Gracilibacillus salitolerans SCU50T (ANI 77.3%, AAI 78.1%). However, the digital DNA-DNA hybridization (19.3-22.1%), average nucleotide identity (71.1-77.4%), and average amino acid identity (66.9-78.6%) values all fell below the recommended thresholds for species delineation, supporting its novel taxonomic status. The major cellular fatty acids were anteiso-C15:0, C16:0, iso-C15:0, and anteiso-C17:0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and aminophospholipids. On the basis of their phenotypic, physiological, biochemical and phylogenetic characteristics, S3-1-1T represented a novel species of the genus Gracilibacillus, for which the name Gracilibacillus pellucidus sp. nov. is proposed, with S3-1-1T (= JCM 36422T = GDMCC 1.4017T) as the type strain.

Population immunity enhances the evolution of SARS-CoV-2 in Beijing revealed by wastewater genomic surveillance

This study aims to elucidate the impact of population immunity on the regional evolution of SARS-CoV-2. A total of 3701 wastewater SARS-CoV-2 concentration values and 168 wastewater whole genomes of SARS-CoV-2 were obtained in Beijing over 11 months following the implementation of the "dynamic zero-COVID" policy adjustments in December 2022. The findings indicate that the number of variant strains identified through wastewater surveillance was 2.46 times greater than that detected by clinical monitoring, with single nucleotide polymorphisms showing an increase of up to 7.14 times. This enhanced surveillance facilitates a more comprehensive analysis of regional virus evolution patterns. Following the adjustment of epidemic measure, Beijing experienced three distinct waves of epidemics, and the dominant variant transitioned directly from BA.5 in the first wave to XBB after six months in the second one. During this period, strong population immunity formed by centralized infection in over 90 % of the population blocked the outbreak of internationally prevalent and concerning variants BQ.1 and CH.1.1, resulting in a 12.5 % faster regional evolution of SARS-CoV-2 strains in Beijing compared to the international context. Subsequently, in August 2023, EG.5 became the dominant variant in the third wave, aligning with international trends. The epidemics in Beijing have caused significant positive selection pressure on SARS-CoV-2 strains, favoring those with enhanced antigenic escape mutations in spike gene. These results underscore that the extensive infection after the adjustment of epidemic prevention policies has accelerated the evolution of SARS-CoV-2 in Beijing and been conducive to antigenic escape evolution, which can effectively inform decision making for epidemic control and preemptive vaccine design.

Molluscan systematics: historical perspectives and the way ahead

Mollusca, the second-most diverse animal phylum, is estimated to have over 100,000 living species with great genetic and phenotypic diversity, a rich fossil record, and a considerable evolutionary significance. Early work on molluscan systematics was grounded in morphological and anatomical studies. With the transition from oligo gene Sanger sequencing to cutting-edge genomic sequencing technologies, molecular data has been increasingly utilised, providing abundant information for reconstructing the molluscan phylogenetic tree. However, relationships among and within most major lineages of Mollusca have long been contentious, often due to limited genetic markers, insufficient taxon sampling and phylogenetic conflict. Fortunately, remarkable progress in molluscan systematics has been made in recent years, which has shed light on how major molluscan groups have evolved. In this review of molluscan systematics, we first synthesise the current understanding of the molluscan Tree of Life at higher taxonomic levels. We then discuss how micromolluscs, which have adult individuals with a body size smaller than 5 mm, offer unique insights into Mollusca's vast diversity and deep phylogeny. Despite recent advancements, our knowledge of molluscan systematics and phylogeny still needs refinement. Further advancements in molluscan systematics will arise from integrating comprehensive data sets, including genome-scale data, exceptional fossils, and digital morphological data (including internal structures). Enhanced access to these data sets, combined with increased collaboration among morphologists, palaeontologists, evolutionary developmental biologists, and molecular phylogeneticists, will significantly advance this field.

A robustly rooted tree of eukaryotes reveals their excavate ancestry

The eukaryote Tree of Life (eToL) depicts the relationships among all eukaryotic organisms; its root represents the Last Eukaryotic Common Ancestor (LECA) from which all extant complex lifeforms are descended1. Locating this root is crucial for reconstructing the features of LECA, both as the endpoint of eukaryogenesis and the start point for the evolution of the myriad complex traits underpinning the diversification of living eukaryotes. However, the position of the root remains contentious due to pervasive phylogenetic artefacts stemming from inadequate evolutionary models, poor taxon sampling and limited phylogenetic signal1. Here we estimate the root of the eToL with unprecedented resolution on the basis of a new, much larger, dataset of mitochondrial proteins that includes all known eukaryotic supergroups. Our analyses of a 100 taxon × 93 protein dataset with state-of-the-art phylogenetic models and an extensive evaluation of alternative hypotheses show that the eukaryotic root lies between two multi-supergroup assemblages: 'Opimoda+' and 'Diphoda+'. This position is consistently supported across different models and robustness analyses. Notably, groups containing 'typical excavates' are placed on both sides of the root, suggesting the complex features of the 'excavate' cell architecture trace back to LECA. This study sheds light on the ancestral cells from which extant eukaryotes arose and provides a crucial framework for investigating the origin and evolution of canonical eukaryotic features.

Isolation and in silico analysis of a new subclass of parasporin 4 from Bacillus thuringiensis coreanensis

Background

Bacillus thuringiensis (Bt) is a Gram-positive bacterium whose strains have been studied mainly for the control of insect pests, due to the insecticidal capacity of its Cry and Vip proteins. However, recent studies indicate the presence of other proteins with no known insecticidal action. These proteins denominated "parasporins" (PS) have cytotoxic activity and are divided into six classes, namely PS1, PS2, PS3, PS4, PS5, and PS6. Among these, parasporins 4 (PS4) has only one described subclass, present in the Bacillus thuringiensis shandongiensis strain. Given the importance and limited knowledge about the actions of PS4 proteins and the existence of only one described subclass, the present work aimed to characterize the Bacillus thuringiensis coreanensis strain as a potential source of PS4 protein.

Methods

A preliminary screening to detect the ps4 gene was conducted in a bank of standard strains and isolates of Bacillus thuringiensis from the Laboratory of Bacterial Genetics and Applied Biotechnology, FCAV/UNESP. The positive strain for this gene had its genomic DNA extracted, the ps4 gene was isolated, cloned and in silico analyses of its sequence were performed. Tools such as Bioedit, BLAST, Clustal Omega, Geneious, IQ-Tree, and iTOL were used in these analyses. For the structural analysis of the PS4 detected, in comparison to the database PS4 (BAD22577), the tools Alphafold2, Pymol, and InterPro were used. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gel analyses allowed the visualization of the inactive and active PS4 protein from the positive strain, after solubilization and activation with Proteinase K.

Results

Previous screening of Bt standard strains revealed the presence of a partial ps4 gene in Bacillus thuringiensis coreanensis strain. The alignment obtained by the BLAST tool revealed 100% identity between the fragment detected in this work with a hypothetical protein (ANN35810.1) from the genome of that same strain. Considering this, the isolation of the complete gene present in this strain was performed by applying the polymer chain reaction (PCR) technique, using the hypothetical sequence as a basis for the primers elaboration. The in silico analysis of the obtained sequence revealed 92.03% similarity with the ps4 sequence presented in the database (AB180980). Protein modeling studies and comparison of their structures revealed that the B. thuringiensis coreanensis has a new subclass of PS4, denominated PS4Ab1, being an important source of parasporin to be explored in biotechnological applications.

Genome-Wide Identification of the NAC Gene Family in Brassica rapa (L.) and Expression Pattern Analysis of BrNAC2s

Flowers are one of the most important organs in plants. Their development serves as a key indicator of the transition from vegetative to reproductive growth and is regulated by various internal signals and environmental factors. NAC (NAM, ATAF, CUC) transcription factors (TFs) play a crucial regulatory role in floral organ development; however, research on the analysis and identification of the NAC TF family in Chinese cabbage (Brassica rapa L.) remains limited. In this study, we performed a comprehensive genome-wide analysis of NACs in B. rapa and identified 279 members of the BrNAC gene family. Their physicochemical properties, domain structure, collinearity relation, and cis-regulatory elements were evaluated. Phylogenetic analysis indicates that NAC proteins from Arabidopsis, B. rapa, B. oleracea, and B. nigra can be classified into seven distinct clades. BrNACs exhibit a tissue-specific expression, and nine BrNACs being specifically expressed in the inflorescence. Furthermore, nine flower-related BrNACs were selected for RT-qPCR analysis to validate their expression profiles. BrNAC2s has been cloned to investigate their subcellular localization, and examine the expression patterns of their promoters in Arabidopsis inflorescences. BrNAC2a and BrNAC2c are highly expressed in stamens while BrNAC2b exhibits elevated expression in pistils and pedicel. Collectively, our findings enhance the understanding of the BrNAC family and provide a foundation for future studies on the molecular mechanisms of BrNACs in floral development.

Backbone phylogeny of Salix based on genome skimming data

The genus Salix is a common component of the Northern Hemisphere dendroflora with important ecological and economic value. However, taxonomy and systematics of Salix is extremely difficult and relationships between main lineages, especially deep phylogenies, remain largely unresolved. In this study, we used genome-skimming, plastome assembly, and single-copy orthologs (SCOs) from 66 Salix accessions, along with publicly available plastome and sequence read archive (SRA) datasets to obtain a robust backbone phylogeny of Salix, clarify relationships between its main lineages, and gain a more precise understanding of the origin and diversification of this species-rich genus. The plastome and SCO datasets resolved Salix into two robust clades, with plastome-based phylogenies lacking inner resolution and SCO offering fully resolved phylogenies. Our results support the classification of Salix into five subgenera: Salix, Urbaniana, Triandrae, Longifoliae and Vetrix. We observed a significant acceleration in the diversification rate within the Chamaetia-Vetrix clade, while Salix exhibited increased rates of diversification spanning from the early Oligocene to the late Miocene. These changes coincided with contemporaneous tectonic and climate change events. Our results provide a foundation for future systematic and evolutionary studies of Salix. Additionally, we showed that genome skimming data is an efficient, rapid, and reliable approach for obtaining extensive genomic data for phylogenomic studies, enabling the comprehensive elucidation of Salix relationships.

Reduced evolutionary constraint accompanies ongoing radiation in deep-sea anglerfishes

Colonization of a novel habitat is often followed by phenotypic diversification in the wake of ecological opportunity. However, some habitats should be inherently more constraining than others if the challenges of that environment offer few evolutionary solutions. We examined this push-and-pull on macroevolutionary diversification following habitat transitions in the anglerfishes (Lophiiformes). We constructed a phylogeny with extensive sampling (1,092 loci and ~38% of species), combined with three-dimensional phenotypic data from museum specimens. We used these datasets to examine the tempo and mode of phenotypic diversification. The deep-sea pelagic anglerfishes originated from a benthic ancestor and shortly after experienced rapid lineage diversification rates. This transition incurred shifts towards larger jaws, smaller eyes and a more laterally compressed body plan. Despite these directional trends, this lineage still evolved high phenotypic disparity in body, skull and jaw shapes. In particular, bathypelagic anglerfishes show high variability in body elongation, while benthic anglerfishes are constrained around optimal shapes. Within this radiation, phenotypic evolution was concentrated among recently diverged lineages, notably those that deviated from the archetypical globose body plan. Taken together, these results demonstrate that spectacular evolutionary radiations can unfold even within environments with few ecological resources and demanding physiological challenges.

Phylogenomic workflow for uncultivable microbial eukaryotes using single-cell RNA sequencing - A case study with planktonic ciliates (Ciliophora, Oligotrichea)

Phylogenetic analyses increasingly rely on genomic and transcriptomic data to produce better supported inferences on the evolutionary relationships among microbial eukaryotes. Such phylogenomic analyses, however, require robust workflows, bioinformatic expertise and computational power. Microbial eukaryotes pose additional challenges given the complexity of their genomes and the presence of non-target sequences (e.g., symbionts, prey) in data obtained from single cells of uncultivable lineages. To address these challenges, we developed a phylogenomic workflow based on single-cell RNA sequencing, integrating all essential steps from cell isolation to data curation and species tree inference. We assessed our workflow by using publicly available and newly generated transcriptomes (11 and 28, respectively) from the Oligotrichea, a diverse group of marine planktonic ciliates. This group's phylogenetic relationships have been relatively well-studied based on ribosomal RNA gene markers, which we reconstructed by read mapping of transcriptome sequences and compared to our phylogenomic inferences. We also compared phylogenomic analyses based on single-copy protein-coding genes (well-curated orthologs) and multi-copy genes (including paralogs) by sequence concatenation and a coalescence approach (Asteroid), respectively. Finally, using subsets of up to 1,014 gene families (GFs), we assessed the influence of missing data in our phylogenomic inferences. All our analyses yielded similar results, and most inferred relationships were consistent and well-supported. Overall, we found that Asteroid provides robust support for species tree inferences, while simplifying curation steps, minimizing the effects of missing data and maximizing the number of GFs represented in the analyses. Our workflow can be adapted for phylogenomic analyses based on single-cell RNA sequencing of other uncultivable microbial eukaryotes.

Can whole genome sequencing resolve taxonomic ambiguities in fungi? The case study of Colletotrichum associated with ferns

Introduction

The genus Colletotrichum comprises numerous fungal species with diverse ecological roles, including plant pathogenic, endophytic, and saprophytic lifestyles. Accurate species identification is crucial for understanding host-pathogen interactions, disease epidemiology, and fungal ecology. However, taxonomic classification within Colletotrichum remains challenging due to genetic complexity and phenotypic plasticity. Conventional approaches such as single-gene analyses and multilocus sequence typing (MLST) frequently fail to resolve closely related taxa, leading to misidentifications that hinder species delimitation and comparative evolutionary studies. Whole-genome sequencing (WGS) offers a promising alternative by providing genome-wide resolution for phylogenetic analysis. This study investigates Colletotrichum isolates associated with the fern Rumohra adiantiformis and evaluates the effectiveness of WGS in addressing taxonomic uncertainties.

Methods

A total of 18 Colletotrichum isolates, including fern-associated strains, were analyzed. Genomic DNA was extracted and sequenced using the Illumina NovaSeq platform. High-quality genome assemblies were generated, and gene prediction was conducted using AUGUSTUS. Orthogroup assignment and phylogenomic analysis were performed based on single-copy orthologs, and phylogenetic trees were constructed using MLST and WGS-based approaches. Comparative analyses were carried out to assess the taxonomic resolution provided by WGS in relation to traditional methods.

Results

Genome-wide phylogenomic analysis revealed distinct evolutionary lineages among Colletotrichum isolates that MLST failed to resolve, highlighting host and geographic differentiation. High-quality genome assemblies were obtained, with 98.3% of genes assigned to orthogroups, indicating strong genomic conservation. Phylogenetic analyses confirmed a close relationship between Rumohra adiantiformis-associated isolates and Colletotrichum filicis, reinforcing the effectiveness of WGS in species identification.

Discussion

These findings demonstrate the superiority of WGS over MLST in resolving species boundaries and reconstructing evolutionary relationships. The enhanced resolution provided by genome-wide data enables more accurate taxonomic classification, reducing misidentifications and improving our understanding of fungal biodiversity. By refining Colletotrichum taxonomy, WGS facilitates ecological and pathogenic studies, offering a robust framework for future research in fungal systematics and plant pathology. As sequencing technologies continue to advance, WGS is expected to become a standard tool for fungal species delineation and evolutionary studies.

Subspecies phylogeny in the human gut revealed by co-evolutionary constraints across the bacterial kingdom

The human gut microbiome contains many bacterial strains of the same species ("strain-level variants") that shape microbiome function. The tremendous scale and molecular resolution at which microbial communities are being interrogated motivates addressing how to describe strain-level variants. We introduce the "Spectral Tree"-an inferred tree of relatedness built from patterns of co-evolutionary constraint between greater than 7,000 diverse bacteria. Using the Spectral Tree to describe over 600 diverse gut commensal strains that we isolated, whole-genome sequenced, and metabolically profiled revealed (1) widespread phylogenetic structure among strain-level variants, (2) the origins of subspecies phylogeny as a shared history of phage infections across humans, and (3) the key role of inter-human strain variation in predicting strain-level metabolic qualities. Overall, our work demonstrates the existence and metabolic importance of structured phylogeny below the level of species for commensal gut bacteria, motivating a redefinition of individual strains according to their evolutionary context. A record of this paper's transparent peer review process is included in the supplemental information.

CamITree: a streamlined software for phylogenetic analysis of viral and mitochondrial genomes

BACKGROUND

Over the past decade, the continuous and rapid advances in bioinformatics have led to an increasingly common use of molecular sequence comparison for phylogenetic analysis. However, the use of multi-software and cross-platform strategies has increased the complexity of phylogenetic tree estimation. Therefore, the development and application of streamlined phylogenetic analysis tools are growing in significance in the field of biology. Particularly for genomes with relatively short sequences, there is a lack of simple and integrative tools for phylogenetic analysis.

RESULTS

In this study, we present CamlTree (Concatenated alignments maximum-likelihood tree), a user-friendly desktop software designed to simplify phylogenetic analysis for viral and mitochondrial genomes, ultimately facilitating related research. CamlTree provides a workflow including gene concatenation (or coalescence), sequence alignment, alignment optimization, and the estimation of phylogenetic trees using both maximum-likelihood (ML) and Bayesian inference (BI) methods. CamlTree was written in TypeScript and developed using the Electron framework. It offers a primarily user-friendly interface based on the React framework.

CONCLUSIONS

CamlTree software has been released for the Windows OS. It integrates several popular analysis tools to optimize and simplify the process of estimating polygenic phylogenetic trees. The establishment of software can assist researchers in reducing their workload and enhancing data processing efficiency, enabling them to expedite their research progress. The software, along with a detailed user manual, is available at https://github.com/BioCrossCoder/camltree .

Identification and expression analysis of the RBOH gene family of Isatis indigotica Fort. and the potential regulation mechanism of RBOH gene on H2O2 under salt stress

KEY MESSAGE

RBOH gene may regulate the resistance of Isatis indigotica Fort. to salt stress by mediating the production of H2O2. RBOH gene plays an important role in plant growth and development, abiotic and biotic stress response, and hormone signalling. However, studies on RBOH gene expression and molecular mechanism of Isatis indigotica Fort. under salt stress have not been reported. This study identified 10 genes of the I. indigotica RBOH gene family (IiRBOH) and divided them into five subfamilies (I-V). Genes within the same class show conserved structural features and similar amino acid sequences. Analysis of CRE suggested that IiRBOH genes might play roles in growth and development, metabolism, hormone regulation, and stress response. Two physiological indicators of I. indigotica treated with salt for different days were detected. It was found that the content of H2O2 in the I. indigotica tissue first increased, then decreased and increased again. The catalase activity also showed a trend of first increasing and then decreasing. The qRT-PCR results showed that these IiRBOH genes showed different expression patterns in response to salt stress, and some of these genes may be involved in the resistance of I. indigotica to salt stress. Through RT-PCR analysis and screening on the PlantCARE website, it was found that IiRBOHA and IiRBOHC not only possess W-box CRE but also exhibit high expression under salt stress. Y1H experiments were conducted with the WRKY genes predicted by phylogenetic analysis to regulate salt stress potentially, and it was discovered that IiWRKY6 and IiWRKY54 can directly activate the transcription of the IiRBOHA gene promoter. This study preliminarily explored the mechanism by which the RBOH gene in I. indigotica mediates H2O2 to resist salt stress, thus laying a foundation for further research on the biological functions of the RBOH gene in I. indigotica.

Writers, readers, and erasers of N6-Methyladenosine (m6A) methylomes in oilseed rape: identification, molecular evolution, and expression profiling

BACKGROUND

m6A RNA modifications are the most prevalent internal modifications in eukaryotic mRNAs and are crucial for plant growth and development, as well as for responses to biotic or abiotic stresses. The modification is catalyzed by writers, removed by erasers, and decoded by various m6A-binding proteins, which are readers. Brassica napus is a major oilseed crop. The dynamic regulation of m6A modifications by writers, erasers, and readers offers potential targets for improving the quality of this crop.

RESULTS

In this study, we identified 92 m6A-regulatory genes in B. napus, including 13 writers, 29 erasers, and 50 readers. A phylogenetic analysis revealed that they could be further divided into four, three, and two clades, respectively. The distribution of protein motifs and gene structures among members of the same clade exhibited notable similarity. During the course of evolution, whole genome duplication (WGD) and segmental duplication were the primary drivers of the expansion of m6A-related gene families. The genes were subjected to rigorous purification selection. Additionally, several sites under positive selection were identified in the proteins. RNA-seq and quantitative real-time PCR (qRT-PCR) expression analyses revealed that the identified Bnam6As exhibit tissue-specific expression patterns, as well as their expression patterns in response to various abiotic and biotic stresses. The 2000 bp sequence upstream of Bnam6As contained a number of cis-acting elements that regulate plant growth and environmental response. Furthermore, the protein interaction network revealed their interactions with a number of proteins of significant functional importance.

CONCLUSION

The identification of m6A modifiers in oilseed rape and their molecular evolution and expression profiling have revealed potential functions and molecular mechanisms of m6A, thus establishing a foundation for further functional validation and molecular breeding.

Enabling efficient analysis of biobank-scale data with genotype representation graphs

Computational analysis of a large number of genomes requires a data structure that can represent the dataset compactly while also enabling efficient operations on variants and samples. However, encoding genetic data in existing tabular data structures and file formats has become costly and unsustainable. Here we introduce the genotype representation graph (GRG), a fully connected hierarchical data structure that losslessly encodes phased whole-genome polymorphisms. Exploiting variant-sharing across samples enables GRG to compress 200,000 UK Biobank phased human genomes to 5-26 gigabytes per chromosome, also enabling graph-traversal algorithms to reuse computed values in random access memory. Constructing and processing GRG files scales to a million whole genomes. Using allele frequencies and association effects as examples, we show that computation on GRG via graph traversal runs the fastest among all tested alternatives. GRG-based algorithms have the potential to increase the scalability and reduce the cost of analyzing large genomic datasets.

Genome-wide characterization and expression analysis of the ADF gene family in response to salt and drought stress in alfalfa (Medicago sativa)

The microfilament cytoskeleton, formed by the process of actin polymerization, serves not only to support the morphology of the cell, but also to regulate a number of cellular activities. Actin-depolymerizing factors (ADFs) represent a significant class of actin-binding proteins that regulate the dynamic alterations in the microfilament framework, thereby playing a pivotal role in plant growth and development. Additionally, they are instrumental in modulating stress responses in plants. The ADF gene family has been explored in various plants, but there was a paucity of knowledge regarding the ADF gene family in alfalfa (Medicago sativa), which is one of the most significant leguminous forage crops globally. In this study, a total of nine ADF genes (designated MsADF1 through MsADF9) were identified in the alfalfa genome and mapped to five different chromosomes. A phylogenetic analysis indicated that the MsADF genes could be classified into four distinct groups, with members within the same group exhibiting comparable gene structures and conserved motifs. The analysis of the Ka/Ks ratios indicated that the MsADF genes underwent purity-based selection during its evolutionary expansion. The promoter region of these genes was found to contain multiple cis-acting elements related to hormone responses, defence, and stress, indicating that they may respond to a variety of developmental and environmental stimuli. Gene expression profiles analyzed by RT-qPCR experiments demonstrated that MsADF genes exhibited distinct expression patterns among different organs. Furthermore, the majority of MsADF genes were induced by salt and drought stress by more than two-fold, with MsADF1, 2/3, 6, and 9 being highly induced, suggesting their critical role in resistance to abiotic stress. These results provide comprehensive information on the MsADF gene family in alfalfa and lay a solid foundation for elucidating their biological function.

WASTER: Practical de novo phylogenomics from low-coverage short reads

The advent of affordable whole-genome sequencing has spurred numerous large-scale projects aimed at inferring the tree of life, yet achieving a complete species-level phylogeny remains a distant goal due to significant costs and computational demands. Traditional species tree inference methods, though effective, are hampered by the need for high-coverage sequencing, high-quality genomic alignments, and extensive computational resources. To address these challenges, this study introduces WASTER, a novel de novo tool for inferring species trees directly from short-read sequences. WASTER employs a k-mer based approach for identifying variable sites, circumventing the need for genome assembly and alignment. Using simulations, we demonstrate that WASTER achieves accuracy comparable to that of traditional alignment-based methods, even for low sequencing depth, and has substantially higher accuracy than other alignment-free methods. We validate WASTER's efficacy on real data, where it accurately reconstructs phylogenies of eukaryotic species with as low depth as 1.5X. WASTER provides a fast and efficient solution for phylogeny estimation in cases where genome assembly and/or alignment may bias analyses or is challenging, for example due to low sequencing depth. It also provides a method for generating guide trees for tree-based alignment algorithms. WASTER's ability to accurately estimate trees from low-coverage sequencing data without relying on assembly and alignment will lead to substantially reduced sequencing and computational costs in phylogenomic projects.

Features and evolutionary adaptations of the mitochondrial genome of Garuga forrestii W. W. Sm

Introduction

Garuga forrestii W. W. Sm. is a tree species of the Burseraceae family, endemic to China, found in hot/warm-dry valleys. This species plays a crucial role in maintaining biodiversity in these ecosystems.

Methods

We performed de novo assembly of the Garuga forrestii mitochondrial genome using PMAT (v.1.5.4), resulting in a typical circular molecule of 606,853 bp. The genome consists of 31 tRNA genes, 3 rRNA genes, 35 protein-coding genes, and 1 pseudogene. The study also investigates RNA editing sites and evolutionary patterns.

Results

The mitochondrial genome exhibits a low proportion of repetitive sequences (3.30%), suggesting a highly conserved structure. A high copy number of the trnM-CAT gene (4 copies) is noted, which may contribute to genomic rearrangement and adaptive evolution. Among the 476 RNA editing sites, hydrophilic-hydrophobic and hydrophobic-hydrophobic editing events are most common, accounting for 77.10%. Negative selection predominates among most genes (Ka/Ks < 1), while a few genes (e.g., matR, nad3, rps1, rps12, and rps4) show signs of positive selection (Ka/Ks > 1), potentially conferring evolutionary advantages. Additionally, a significant A/T bias is observed at the third codon position. Phylogenomic analysis supports the APG IV classification, with no evidence of horizontal gene transfer.

Discussion

This mitochondrial genome offers valuable insights into the adaptive mechanisms and evolutionary processes of Garuga forrestii. It enhances our understanding of the species' biogeography in tropical Southeast Asia and Southwest China, providing key information on the evolutionary history of this genus.

getphylo: rapid and automatic generation of multi-locus phylogenetic trees

BACKGROUND

The increasing amount of genomic data calls for tools that can create genome-scale phylogenies quickly and efficiently. Existing tools rely on large reference databases or require lengthy de novo calculations to identify orthologues, meaning that they have long run times and are limited in their taxonomic scope. To address this, we created getphylo, a python tool for the rapid generation of phylogenetic trees de novo from annotated sequences.

RESULTS

We present getphylo (Genbank to Phylogeny), a tool that automatically builds phylogenetic trees from annotated genomes alone. Orthologues are identified heuristically by searching for singletons (single copy genes) across all input genomes and the phylogeny is inferred from a concatenated alignment of all coding sequences by maximum likelihood. We performed a thorough benchmarking of getphylo against two existing tools, autoMLST and GTDB-tk, to show that it can produce trees of comparable quality in a fraction of the time. We also demonstrate the flexibility of getphylo across four case studies including bacterial and eukaryotic genomes, and biosynthetic gene clusters.

CONCLUSIONS

getphylo is a quick and reliable tool for the automated generation of genome-scale phylogenetic trees. getphylo can produce phylogenies comparable to other software in a fraction of the time, without the need large local databases or intense computation. getphylo can rapidly identify orthologues from a wide variety of datasets regardless of taxonomic or genomic scope. The usability, speed, flexibility of getphylo makes it a valuable addition to the phylogenetics toolkit.

Genetic Diversity and Population Structure of Macrobrachium nipponense Populations in the Saline-Alkaline Regions of China

The oriental river prawn Macrobrachium nipponense is of great economic importance in China. However, its culture in the saline-alkaline regions is limited. This study used D-loop region sequences to analyze the genetic diversity and population structure across the saline-alkaline regions of China. A total of 264 individuals were successfully sequenced from nine sites, including Daqing in Heilongjiang Province (HLJ), Songyuan in Jilin Province (JL), Ulanhot in the east of inner Mongolia (NMG), Jingtai in Gansu Province (GS), Dongying in Shandong Province (SD), Dongtai in Jiangsu Province (JS), Nanchang in Jiangxi province (JX), Tianjin in mainland China (TJ), and Yinchuan in Ningxia Province (NX). In addition, 89 haplotypes were defined. The haplotype diversity (h) and nucleotide diversity π showed remarkable genetic diversity in the JS, NX, JL, and TJ sites. It was found that the genetic variation within sites was relatively greater. The genetic distance (D) and the pairwise genetic differentiation index (FST) revealed that SD and GS are closely related. The FST values among the nine sites were significant except for the one between SD and HLJ (p-value > 0.05). The cluster analyses and the phylogenetic tree identified two main groups. There is an association among sites by geographic location, and the JS site shows higher diversity. The results of this study provide basic information for the protection and development of M. nipponense resources in the saline-alkaline regions of China.

Modeling compositional heterogeneity resolves deep phylogeny of flowering plants

Angiosperms experienced one of the most remarkable radiations of land plants and are now the dominant autotrophs in terrestrial ecosystems. Recent phylogenomic studies based on large-scale data from plastid, mitochondrial, or nuclear transcriptomes/genomes and increased taxon sampling have provided unprecedent resolution into the phylogeny of flowering plants. However, owing to ancient rapid radiations, the interrelationships among the five lineages of Mesangiospermae, the vast majority of angiosperms, remain contentious. Here we show that, although plastid and mitochondrial genomes lack sufficient phylogenetic signal for resolving deeper phylogeny, the relationships among five mesangiosperm lineages can be confidently resolved under better-fitting models using genome-scale data. According to our Bayesian cross-validation and model test in a maximum likelihood framework, site-heterogeneous models (e.g., CAT-GTR + G4, LG + C20 + F + G) outperform site-homogeneous or partition models often used in previous studies. Under site-heterogeneous models, the approximately unbiased test favored our preferred tree recovered from various datasets: Ceratophyllales (coontails) are robustly recovered as sister to monocots, and they together are sister to the clade comprising magnoliids, Chloranthales, and eudicots. Our phylogenomic analyses resolve the last enigma of the deeper phylogeny of angiosperms and emphasize the efficacy of modeling compositional heterogeneity in resolving rapid radiations of plants.

A GH1 β-glucosidase from the Fervidobacterium pennivorans DSM9078 showed extraordinary thermostability and distinctive ability in the efficient transformation of ginsenosides

A novel GH1 β-glucosidase Fpglu1 from Fervidobacterium pennivorans DSM9078 was successfully cloned and expressed in Escherichia coli. This hyperthermophilic enzyme possesses unique features that make it valuable in biochemistry and pharmacology. It exhibited optimal activity at temperatures exceeding 100 °C, a trait rarely observed in other enzymes, and demonstrated extraordinary thermostability. It displayed multifunctional activity, with the highest activity observed for p-nitrophenyl-β-d-glucopyranoside (pNPGlu) at 92.47 U/mg. Furthermore, the distinctive capacity of Fpglu1 to transform ginsenosides (Rb1, Rb2, and Rc) into Compound-K (C-K) sets it apart from the other enzymes. It effectively cleaved the external β-(1-6) glycosidic linkage at the C-20 position of ginsenosides Rb1, Rb2, and Rc, followed by hydrolysis ofthe internal glycosidic bond connected to the C-3 position. The kcat/Km value of Fpglu1 for Rb1 was 453 ± 1.27 mM-1/s, significantly higher than those of Fpglu1 for other ginsenosides. The crystal structure of Fpglu1, determined at 1.85 Å resolution, provided a deeper understanding of its catalysis and substrate specificity. The evaluation of the binding conformation, hydrogen bond, and key amino acids of β-glucosidase Fpglu1 with different ginsenosides (Rb1, Rb2, and Rc) further elucidated the structural basis of its substrate-binding preference. In summary, Fpglu1, which had excellent thermostability and unique ginsenoside-transforming ability, was a highly promising catalyst for the industrial production of ginsenoside C-K. Additionally, structural studies have laid a theoretical foundation for further improving the catalytic properties of the enzyme through directed evolution in the future.

A new species of Elodophthalmus from Lower Cretaceous Lebanese amber unravels the systematic placement of Elodophthalmidae and reconciling phylogenetic conflicts within Tenebrionoidea

Elodophthalmidae, represented by the sole genus Elodophthalmus Kirejtshuk & Azar, is an extinct beetle family described from Lower Cretaceous Lebanese amber. Elodophthalmidae has been hypothesized to share close affinities with the extant superfamily Scirtoidea, but their exact systematic position remains elusive. Here, we describe a new species of Elodophthalmus, Elodophthalmus maksoudae sp. nov., based on a well-preserved fossil from Early Cretaceous amber collected in Hammana/Mdeyrij, Central Lebanon, the same locality as other congeneric species. Using improved imaging technologies, we reveal detailed morphological characters of the fossil, providing critical evidence for a more robust systematic placement of Elodophthalmus. Our findings present compelling evidence supporting the placement of Elodophthalmidae within the superfamily Tenebrionoidea. Furthermore, we highlight that conflicts in the interfamilial relationships within Tenebrionoidea across various datasets can, at least partially, be mitigated by adopting the site-heterogeneous CAT-GTR+G model. We suggest that the traditional reliance on site-homogeneous models in Sanger sequencing-based studies may fail to capture the complexities of nucleotide substitution patterns. With the increasing recognition of the importance of modeling among-site compositional heterogeneity, our study points to the necessity for more rigorous model testing in the phylogenetic studies of ancient lineages such as Tenebrionoidea.

MEGA12: Molecular Evolutionary Genetic Analysis Version 12 for Adaptive and Green Computing

We introduce the 12th version of the Molecular Evolutionary Genetics Analysis (MEGA12) software. This latest version brings many significant improvements by reducing the computational time needed for selecting optimal substitution models and conducting bootstrap tests on phylogenies using maximum likelihood (ML) methods. These improvements are achieved by implementing heuristics that minimize likely unnecessary computations. Analyses of empirical and simulated datasets show substantial time savings by using these heuristics without compromising the accuracy of results. MEGA12 also links-in an evolutionary sparse learning approach to identify fragile clades and associated sequences in evolutionary trees inferred through phylogenomic analyses. In addition, this version includes fine-grained parallelization for ML analyses, support for high-resolution monitors, and an enhanced Tree Explorer. MEGA12 can be downloaded from https://www.megasoftware.net.

A land plant phylogenetic framework for GLABROUS INFLORESCENCE STEMS (GIS), SUPERMAN, JAGGED and allies plus their TOPLESS co-repressor

Members of the plant specific family of C1-1i zincfinger transcriptionfactors (ZF-TFs), such as SUPERMAN, JAGGED, KNUCKLES or GIS,regulatediversedevelopmental processes including sexual reproduction. C1-1is consist of one zinc-finger and one to two EAR domains, connected by large intrinsically disordered regions (IDR). While the role of C1-i1 ZF-TFs in development processes is well known for some genes in Arabidopsis, rice or tomatoa comprehensive and broadphylogenetic background is lacking, yet knowledge of orthology is a requirement for a better understanding of C1-1i-Zf-TFs diverse roles in plants. Here, we provide a fine-grained and land plant wide classification of C1-1i sub-families and their known co-repressors TOPLESS and TOPLESS RELATED. Our work combines the identification of orthologous groups with Maximum-Likelihood phylogeny reconstructions and digital gene expression analyses mining high quality land plant genomes and transcriptomes to generate a comprehensive framework of C1-1i ZF-TF evolution. We show that C1-1i's are low to moderate copy genesand that orthologous genesonly partiallyhaveconserved sub-family and life cycle stage dependent expression pattern across land plants while others are highly diverged. Our workprovides the phylogenetic framework for C1-1i ZF-TFs, s and strengthen C1-1 ZF-TFs as a potential model for IDR-research in plants.

Phylogenomic analyses of the pantropical Platycerium Desv. (Platycerioideae) reveal their complex evolution and historical biogeography

Platycerium is a genus of pantropical epiphytic ferns consisting of ca. 18 species and are highly sought after by horticultural enthusiasts. Although the monophyly of this genus has been well supported in previous molecular studies, as an intercontinentally disjunct genus, the origin and distribution pattern of Platycerium were elusive and controversial. This is mainly due to limited taxon sampling, a plastid representing only a single coalescent history, the lack of fossil evidence, and so on. Here, by utilizing genome-skimming sequencing, transcriptome sequencing, and flow cytometry, we integrated chloroplast genomes, data of single-copy nuclear genes, ploidy levels, morphology, and geographic distribution to understand the species phylogeny and the evolutionary and biogeographic history of Platycerium. Our major results include: (1) based on both plastid and nuclear datasets, Platycerium is consistently resolved into three fully supported clades: the Afro-American (AA) clade, the Javan-Australian (JA) clade, and the Malayan-Asian (MA) clade. The AA clade and MA clade are further divided into three and two subclades, respectively; (2) a large amount of gene tree conflict, as well as cytonuclear discordance, was found and can be explained by hybridization and incomplete lineage sorting, and most of the hybridization hypotheses represented ancient hybridization events; (3) through molecular dating, the crown age of Platycerium is determined to be at approximately 32.79 Ma based on the plastid dataset or 29.08 Ma based on the nuclear dataset in the Middle Oligocene; (4) ancestral area reconstruction analysis from different datasets showed that Platycerium most likely originated from Indochina; (5) current distribution patterns are resultant from long-distance dispersals, ancient orogeny, and an ancient climate event; and (6) species diversification was driven by polyploidization, dispersal, and hybridization. This study presented here will help understand the evolution of tropical plant flora and provide a reference for the cultivation and breeding of staghorn ferns.

Reticulate evolution: Detection and utility in the phylogenomics era

Phylogenomics has enriched our understanding that the Tree of Life can have network-like or reticulate structures among some taxa and genes. Two non-vertical modes of evolution - hybridization/introgression and horizontal gene transfer - deviate from a strictly bifurcating tree model, causing non-treelike patterns. However, these reticulate processes can produce similar patterns to incomplete lineage sorting or recombination, potentially leading to ambiguity. Here, we present a brief overview of a phylogenomic workflow for inferring organismal histories and compare methods for distinguishing modes of reticulate evolution. We discuss how the timing of coalescent events can help disentangle introgression from incomplete lineage sorting and how horizontal gene transfer events can help determine the relative timing of speciation events. In doing so, we identify pitfalls of certain methods and discuss how to extend their utility across the Tree of Life. Workflows, methods, and future directions discussed herein underscore the need to embrace reticulate evolutionary patterns for understanding the timing and rates of evolutionary events, providing a clearer view of life's history.

Haplotype-Based Approach Represents Locus Specificity in the Genomic Diversification Process in Humans (Homo sapiens)

BACKGROUND/OBJECTIVES

Recent progress in evolutionary genomics on human (Homo sapiens) populations has revealed complex demographic events and genomic changes. These include population expansion with complicated migration, substantial population structure, and ancient introgression from other hominins, as well as human characteristics selections. Nevertheless, the genomic regions in which such evolutionary events took place have remained unclear.

METHODS

Here, we focused on eight loci containing the haplotypes that were previously presented as atypical for the mutation pattern in sequence and/or geographic distribution pattern with the model of recent African origin, which constitute two major clusters: African only, and global. This was the consensus model before information regarding introgression from Neanderthal (Homo neanderthalensis) was available. We compared diversity in identical datasets of the modern human population genome, with the 1000 Genomes project among them.

RESULTS/CONCLUSIONS

This study identified representative genomic regions that show traces of various demographic events and genomic changes that modern humans have undergone by categorizing the relationships in sequence similarity and in worldwide geographic distribution among haplotypes.

Investigating the genomic and metabolic abilities of PGPR Pseudomonas fluorescens in promoting plant growth and fire blight management

Pseudomonas fluorescens is commonly found in diverse environments and is well known for its metabolic and antagonistic properties. Despite its remarkable attributes, its potential role in promoting plant growth remains unexplored. This study examines these traits across 14 strains residing in diverse rhizosphere environments through pangenome and comparative genome analysis, alongside molecular docking studies against Erwinia amylovora to combat fire blight. Whole genome analysis revealed circular chromosome (6.01-7.07 Mb) with GC content averaging 59.95-63.39%. Predicted genes included 16S rRNA and protein-coding genes ranging from 4435 to 6393 bp and 1527 to 1541 bp, respectively. Pangenome analysis unveiled an open pangenome, shedding light on genetic factors influencing plant growth promotion and biocontrol, including nitrogen fixation, phosphorus solubilization, siderophore production, stress tolerance, flagella biosynthesis, and induced systemic resistance. Furthermore, pyrrolnitrin, phenazine-1-carboxylic acid, pyoluteorin, lokisin, 2,4-diacetylpholoroglucinol and pseudomonic acid were identified. Molecular docking against key proteins of E. amylovora highlighted the high binding affinities of 2,4-diacetylphloroglucinol, pseudomonic acid, and lokisin. These findings underscore the multifaceted role of P. fluorescens in plant growth promotion and biocontrol, with key biomolecules showing promising applications in plant growth and defense against pathogens.

Comparative Mitogenomics Provides Valuable Insights for the Phylogeny and New DNA Barcodes of Ganoderma

Ganoderma is the most important genus in the family Ganodermataceae; many species have attracted much attention and widely cultivated because of their medicinal values, but so far, not a sequenced mitogenome derived from dikaryon strains has been explicitly recorded. Herein, four novel mitogenomes of commonly cultivated Ganoderma (G. leucocontextum H4, G. lucidum G6, G. sinense MZ96 and G. tsugae SS) were de novo assembled and given detail functional annotations. Collinearity analysis revealed that the four mitogenomes shared 82.93-92.02% similarity with their corresponding reference mitogenomes at the nucleotide level. A total of 15 core protein-coding genes (PCGs), along with rrnL and rrnS (mtLSU and mtSSU) were chosen as potential candidates for constructing their individual phylogenetic trees. These trees were compared with those derived from the concatenated sequences of 15 core PCGs. And finally, we found that the atp9 and nad4L were the most reliable markers for the phylogenetic analysis of Ganoderma and chosen as standard sequences to generate new DNA barcodes. This finding was further verified by comparing it against almost all available Ganoderma mitogenomes in the NCBI, with Trametes versicolor (Polyporaceae) and Rigidoporus microporus (Meripilaceae) as two outgroups. A total of 52 mitogenomes from three families were highly conserved, with identical gene lengths for atp9 (222 bp) and nad4L (267 bp). These genes were capable of distinguish distinctly different various species, which are grouped into separate clades within the phylogenetic trees. The closest related clades (I and II), including at least 30 samples of the three classical taxonomic species (G. lingzhi, G. sichuanense and G. lucidum), differed in only one SNP. The single base mutation rate increased with the evolutionary divergence of the phylogenetic clades, from two to three SNPs in earlier clades (e.g., clade IV containing G. leucocontextum) to five to six SNPs in later clades (e.g., clade X containing G. sinense). Despite these variations between species, the atp9 and nad4L genes of Ganoderma mitogenomes consistently encoded the same ATP synthase F0 subunit c (73 aa) and NADH dehydrogenase subunit 4L (88 aa). These two genes have been identified as reliable markers of new DNA barcodes, offering valuable insights and contributing significantly to understanding the evolutionary relationships and phylogeny of the Ganoderma genus and even the Ganodermataceae family.

Beyond genes-for-behaviour: The potential for genomics to resolve long-standing questions in avian brood parasitism

Behavioural ecology by definition of its founding 'Tinbergian framework' is an integrative field, however, it lags behind in incorporating genomic methods. 'Finding the gene/s for a behaviour' is still rarely feasible or cost-effective in the wild but as we show here, genomic data can be used to address broader questions. Here we use avian brood parasitism, a model system in behavioural ecology as a case study to highlight how behavioural ecologists could use the full potential of state-of-the-art genomic tools. Brood parasite-host interactions are one of the most easily observable and amenable natural laboratories of antagonistic coevolution, and as such have intrigued evolutionary biologists for decades. Using worked examples, we demonstrate how genomic data can be used to study the causes and mechanisms of (co)evolutionary adaptation and answer three key questions for the field: (i) Where and when should brood parasitism evolve?, (ii) When and how should hosts defend?, and (iii) Will coevolution persist with ecological change? In doing so, we discuss how behavioural and molecular ecologists can collaborate to integrate Tinbergen's questions and achieve the coherent science that he promoted to solve the mysteries of nature.

Collapsible tree: interactive web app to present collapsible hierarchies

MOTIVATION

A crucial component of intuitive data visualization is presenting a hierarchical tree structure with interactive functions. For example, single-cell transcriptomics studies may generate gene expression values with developmental trajectories or cell lineage structures. Two common visualization methods, t-Distributed Stochastic Neighbor Embedding (t-SNE) and Uniform Manifold Approximation and Projection (UMAP), require two separate figures to depict the distribution of cell types and gene expression data, with low-dimension projections that may not capture the hierarchical structures among cells.

RESULTS

Here, we present a JavaScript framework and an interactive web app named Collapsible Tree, which presents values jointly with interactive, expandable, and collapsible lineage structures. For example, the Collapsible Tree presents cellular states and gene expression from single-cell transcriptomics within a single hierarchical plot, enabling comparisons of gene expression across lineages and subtle patterns between sub-lineages. Our framework can facilitate the exploration of complicated value patterns that are not evident in UMAP or t-SNE plots.

AVAILABILITY AND IMPLEMENTATION

The Collapsible Tree web interface is available at https://collapsibletree.data2in.net. The JavaScript library source code is available at https://github.com/data2intelligence/collapsible_tree.

Sequential Bayesian Phylogenetic Inference

The ideal approach to Bayesian phylogenetic inference is to estimate all parameters of interest jointly in a single hierarchical model. However, this is often not feasible in practice due to the high computational cost. Instead, phylogenetic pipelines generally consist of sequential analyses, whereby a single point estimate from a given analysis is used as input for the next analysis (e.g., a single multiple sequence alignment is used to estimate a gene tree). In this framework, uncertainty is not propagated from step to step, which can lead to inaccurate or spuriously confident results. Here, we formally develop and test a sequential inference approach for Bayesian phylogenetic inference, which uses importance sampling to generate observations for the next step of an analysis pipeline from the posterior distribution produced in the previous step. Our sequential inference approach presented here not only accounts for uncertainty between analysis steps but also allows for greater flexibility in software choice (and hence model availability) and can be computationally more efficient than the traditional joint inference approach when multiple models are being tested. We show that our sequential inference approach is identical in practice to the joint inference approach only if sufficient information in the data is present (a narrow posterior distribution) and/or sufficiently many important samples are used. Conversely, we show that the common practice of using a single point estimate can be biased, for example, a single phylogeny estimate can transform an unrooted phylogeny into a time-calibrated phylogeny. We demonstrate the theory of sequential Bayesian inference using both a toy example and an empirical case study of divergence-time estimation in insects using a relaxed clock model from transcriptome data. In the empirical example, we estimate 3 posterior distributions of branch lengths from the same data (DNA character matrix with a GTR+Γ+I substitution model, an amino acid data matrix with empirical substitution models, and an amino acid data matrix with the PhyloBayes CAT-GTR model). Finally, we apply 3 different node-calibration strategies and show that divergence time estimates are affected by both the data source and underlying substitution process to estimate branch lengths as well as the node-calibration strategies. Thus, our new sequential Bayesian phylogenetic inference provides the opportunity to efficiently test different approaches for divergence time estimation, including branch-length estimation from other software.

Integrating Genomic Data with the Development of CRISPR-Based Point-of-Care-Testing for Bacterial Infections

Purpose of Review

Bacterial infections and antibiotic resistance contribute to global mortality. Despite many infections being preventable and treatable, the lack of reliable and accessible diagnostic tools exacerbates these issues. CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)-based diagnostics has emerged as a promising solution. However, the development of CRISPR diagnostics has often occurred in isolation, with limited integration of genomic data to guide target selection. In this review, we explore the synergy between bacterial genomics and CRISPR-based point-of-care tests (POCT), highlighting how genomic insights can inform target selection and enhance diagnostic accuracy.

Recent Findings

We review recent advances in CRISPR-based technologies, focusing on the critical role of target sequence selection in improving the sensitivity of CRISPR-based diagnostics. Additionally, we examine the implementation of these technologies in resource-limited settings across Asia and Africa, presenting successful case studies that demonstrate their potential.

Summary

The integration of bacterial genomics with CRISPR technology offers significant promise for the development of effective point-of-care diagnostics.

Predicting Phylogenetic Bootstrap Values via Machine Learning

Estimating the statistical robustness of the inferred tree(s) constitutes an integral part of most phylogenetic analyses. Commonly, one computes and assigns a branch support value to each inner branch of the inferred phylogeny. The still most widely used method for calculating branch support on trees inferred under maximum likelihood (ML) is the Standard, nonparametric Felsenstein bootstrap support (SBS). Due to the high computational cost of the SBS, a plethora of methods has been developed to approximate it, for instance, via the rapid bootstrap (RB) algorithm. There have also been attempts to devise faster, alternative support measures, such as the SH-aLRT (Shimodaira-Hasegawa-like approximate likelihood ratio test) or the UltraFast bootstrap 2 (UFBoot2) method. Those faster alternatives exhibit some limitations, such as the need to assess model violations (UFBoot2) or unstable behavior in the low support interval range (SH-aLRT). Here, we present the educated bootstrap guesser (EBG), a machine learning-based tool that predicts SBS branch support values for a given input phylogeny. EBG is on average 9.4 (σ=5.5) times faster than UFBoot2. EBG-based SBS estimates exhibit a median absolute error of 5 when predicting SBS values between 0 and 100. Furthermore, EBG also provides uncertainty measures for all per-branch SBS predictions and thereby allows for a more rigorous and careful interpretation. EBG can, for instance, predict SBS support values on a phylogeny comprising 1,654 SARS-CoV2 genome sequences within 3 h on a mid-class laptop. EBG is available under GNU GPL3.

Genome-Wide Identification of the Geranylgeranyl Pyrophosphate Synthase (GGPS) Gene Family Associated with Natural Rubber Synthesis in Taraxacum kok-saghyz L. Rodin

Taraxacum kok-saghyz Rodin (TKS) is a recognized alternative source of natural rubber comparable to the rubber tree. The geranylgeranyl pyrophosphate synthase (GGPS) catalyzed the synthesis of geranylgeranyl pyrophosphate (GGPP), which is an important enzyme in the secondary metabolism pathway. In this study, we present the first analysis of the GGPS gene family in TKS, where a total of seven TkGGPS family members were identified. Their core motifs, conserved structural domains, gene structures, and cis-acting elements were described. In addition, two phylogenetic trees were constructed based on the Neighbor-Joining and Maximum-Likelihood methods, and the TkGGPSs were highly conserved and exhibited good collinearity with the other species. Transcriptome data showed that seven TkGGPS gene members were expressed in all the 12 tissues measured, and TkGGPS1, TkGGPS3, and TkGGPS6 were highly expressed in latex, suggesting that they may be associated with natural rubber synthesis. Meanwhile, quantitative real-time PCR (qRT-PCR) showed that the expression levels of the TkGGPS genes were regulated by the ethylene and methyl jasmonate (MeJA) pathways. Subcellular localization results indicated that all the TkGGPS proteins were also located in chloroplasts involved in photosynthesis in plants. This study will provide valuable insights into the selection of candidate genes for molecular breeding and natural rubber biosynthesis in TKS.

Phylogenomics supports a single origin of terrestriality in isopods

Terrestriality, the adaptation to life on land, is one of the key evolutionary transitions, occurring numerous times across the tree of life. Within Arthropoda, there have been several independent transitions: in hexapods, myriapods, arachnids and isopods. Isopoda is a morphologically diverse order within Crustacea, with species adapted to almost every environment on Earth. The order is divided into 11 suborders with the most speciose, Oniscidea, including terrestrial isopods such as woodlice and sea-slaters. Recent molecular phylogenetic studies have challenged traditional isopod morphological taxonomy, suggesting that several well-accepted suborders, including Oniscidea, may be non-monophyletic. This implies that terrestriality may have evolved multiple times. Current molecular hypotheses, however, are based on limited sequence data. Here, I collate available genome and transcriptome datasets for 36 isopods and four peracarid crustaceans from public sources, generate assemblies and use 970 single-copy orthologues to estimate isopod relationships and divergence times with molecular dating. The resulting phylogenetic analyses support monophyly of terrestrial isopods and suggest conflicting relationships based on nuclear ribosomal RNA sequences may be caused by long-branch attraction. Dating analyses suggest a Permo-Carboniferous origin of isopod terrestriality, much more recently than other terrestrial arthropods.

Bioinformatics Goes Viral: I. Databases, Phylogenetics and Phylodynamics Tools for Boosting Virus Research

Computer-aided analysis of proteins or nucleic acids seems like a matter of course nowadays; however, the history of Bioinformatics and Computational Biology is quite recent. The advent of high-throughput sequencing has led to the production of "big data", which has also affected the field of virology. The collaboration between the communities of bioinformaticians and virologists already started a few decades ago and it was strongly enhanced by the recent SARS-CoV-2 pandemics. In this article, which is the first in a series on how bioinformatics can enhance virus research, we show that highly useful information is retrievable from selected general and dedicated databases. Indeed, an enormous amount of information-both in terms of nucleotide/protein sequences and their annotation-is deposited in the general databases of international organisations participating in the International Nucleotide Sequence Database Collaboration (INSDC). However, more and more virus-specific databases have been established and are progressively enriched with the contents and features reported in this article. Since viruses are intracellular obligate parasites, a special focus is given to host-pathogen protein-protein interaction databases. Finally, we illustrate several phylogenetic and phylodynamic tools, combining information on algorithms and features with practical information on how to use them and case studies that validate their usefulness. Databases and tools for functional inference will be covered in the next article of this series: Bioinformatics goes viral: II. Sequence-based and structure-based functional analyses for boosting virus research.

Insertions and Deletions: Computational Methods, Evolutionary Dynamics, and Biological Applications

Insertions and deletions constitute the second most important source of natural genomic variation. Insertions and deletions make up to 25% of genomic variants in humans and are involved in complex evolutionary processes including genomic rearrangements, adaptation, and speciation. Recent advances in long-read sequencing technologies allow detailed inference of insertions and deletion variation in species and populations. Yet, despite their importance, evolutionary studies have traditionally ignored or mishandled insertions and deletions due to a lack of comprehensive methodologies and statistical models of insertions and deletion dynamics. Here, we discuss methods for describing insertions and deletion variation and modeling insertions and deletions over evolutionary time. We provide practical advice for tackling insertions and deletions in genomic sequences and illustrate our discussion with examples of insertions and deletion-induced effects in human and other natural populations and their contribution to evolutionary processes. We outline promising directions for future developments in statistical methodologies that would allow researchers to analyze insertions and deletion variation and their effects in large genomic data sets and to incorporate insertions and deletions in evolutionary inference.

From sequences to sustainability: Exploring dipterocarp genomes for oleoresin production, timber quality, and conservation

Dipterocarp species dominate tropical forest ecosystems and provide key ecological and economic value through their use of aromatic resins, medicinal chemicals, and high-quality timber. However, habitat loss and unsustainable logging have endangered many Dipterocarpaceae species. Genomic strategies provide new opportunities for both elucidating the molecular pathways underlying these desirable traits and informing conservation efforts for at-risk taxa. This review summarizes the progress in dipterocarp genomics analysis and applications. We describe 16 recently published Dipterocarpaceae genome sequences, representing crucial genetic blueprints. Phylogenetic comparisons delineate evolutionary relationships among species and provide frameworks for pinpointing functional changes underlying specialized metabolism and wood development patterns. We also discuss connections revealed thus far between specific gene families and both oleoresin biosynthesis and wood quality traits-including the identification of key terpenoid synthases and cellulose synthases likely governing pathway flux. Moreover, the characterization of adaptive genomic markers offers vital resources for supporting conservation practices prioritizing resilient genotypes displaying valuable oleoresin and timber traits. Overall, progress in dipterocarp functional and comparative genomics provides key tools for addressing the intertwined challenges of preserving biodiversity in endangered tropical forest ecosystems while sustainably deriving aromatic chemicals and quality lumber that support diverse human activities.

Phylogenomic analyses revealed widely occurring hybridization events across Elsholtzieae (Lamiaceae)

Obtaining a robust phylogeny proves challenging due to the intricate evolutionary history of species, where processes such as hybridization and incomplete lineage sorting can introduce conflicting signals, thereby complicating phylogenetic inference. In this study, we conducted comprehensive sampling of Elsholtzieae, with a particular focus on its largest genus, Elsholtzia. We utilized 503 nuclear loci and complete plastome sequences obtained from 99 whole-genome sequencing datasets to elucidate the interspecific relationships within the Elsholtzieae. Additionally, we explored various sources of conflicts between gene trees and species trees. Fully supported backbone phylogenies were recovered, and the monophyly of Elsholtzia and Keiskea was not supported. Significant gene tree heterogeneity was observed at numerous nodes, particularly regarding the placement of Vuhuangia and the E. densa clade. Further investigations into potential causes of this discordance revealed that incomplete lineage sorting (ILS), coupled with hybridization events, has given rise to substantial gene tree discordance. Several species, represented by multiple samples, exhibited a closer association with geographical distribution rather than following a strictly monophyletic pattern in plastid trees, suggesting chloroplast capture within Elsholtzieae and providing evidence of hybridization. In conclusion, this study provides phylogenomic insights to untangle taxonomic problems in the tribe Elsholtzieae, especially the genus Elsholtzia.

The emerging view on the origin and early evolution of eukaryotic cells

The origin of the eukaryotic cell, with its compartmentalized nature and generally large size compared with bacterial and archaeal cells, represents a cornerstone event in the evolution of complex life on Earth. In a process referred to as eukaryogenesis, the eukaryotic cell is believed to have evolved between approximately 1.8 and 2.7 billion years ago from its archaeal ancestors, with a symbiosis with a bacterial (proto-mitochondrial) partner being a key event. In the tree of life, the branch separating the first from the last common ancestor of all eukaryotes is long and lacks evolutionary intermediates. As a result, the timing and driving forces of the emergence of complex eukaryotic features remain poorly understood. During the past decade, environmental and comparative genomic studies have revealed vital details about the identity and nature of the host cell and the proto-mitochondrial endosymbiont, enabling a critical reappraisal of hypotheses underlying the symbiotic origin of the eukaryotic cell. Here we outline our current understanding of the key players and events underlying the emergence of cellular complexity during the prokaryote-to-eukaryote transition and discuss potential avenues of future research that might provide new insights into the enigmatic origin of the eukaryotic cell.

Genotype Representation Graphs: Enabling Efficient Analysis of Biobank-Scale Data

Computational analysis of a large number of genomes requires a data structure that can represent the dataset compactly while also enabling efficient operations on variants and samples. Current practice is to store large-scale genetic polymorphism data using tabular data structures and file formats, where rows and columns represent samples and genetic variants. However, encoding genetic data in such formats has become unsustainable. For example, the UK Biobank polymorphism data of 200,000 phased whole genomes has exceeded 350 terabytes (TB) in Variant Call Format (VCF), cumbersome and inefficient to work with. To mitigate the computational burden, we introduce the Genotype Representation Graph (GRG), an extremely compact data structure to losslessly present phased whole-genome polymorphisms. A GRG is a fully connected hierarchical graph that exploits variant-sharing across samples, leveraging ideas inspired by Ancestral Recombination Graphs. Capturing variant-sharing in a multitree structure compresses biobank-scale human data to the point where it can fit in a typical server's RAM (5-26 gigabytes (GB) per chromosome), and enables graph-traversal algorithms to trivially reuse computed values, both of which can significantly reduce computation time. We have developed a command-line tool and a library usable via both C++ and Python for constructing and processing GRG files which scales to a million whole genomes. It takes 160GB disk space to encode the information in 200,000 UK Biobank phased whole genomes as a GRG, more than 13 times smaller than the size of compressed VCF. We show that summaries of genetic variants such as allele frequency and association effect can be computed on GRG via graph traversal that runs significantly faster than all tested alternatives, including vcf.gz, PLINK BED, tree sequence, XSI, and Savvy. Furthermore, GRG is particularly suitable for doing repeated calculations and interactive data analysis. We anticipate that GRG-based algorithms will improve the scalability of various types of computation and generally lower the cost of analyzing large genomic datasets.

Transcriptome-associated metabolomics reveals the molecular mechanism of flavonoid biosynthesis in Desmodium styracifolium (Osbeck.) Merr under abiotic stress

The primary pharmacological components of Desmodium styracifolium (Osbeck.) Merr. are flavonoids, which have a broad range of pharmacological effects and are important in many applications. However, there have been few reports on the molecular mechanisms underlying flavonoid biosynthesis in the pharmacodynamic constituents of D. styracifolium. Flavonoid biosynthesis in D. styracifolium pharmacodynamic constituents has, however, been rarely studied. In this study, we investigated how salt stress, 6-BA (6-Benzylaminopurine) treatment, and PEG 6000-simulated drought stress affect flavonoid accumulation in D. styracifolium leaves. We integrated metabolomics and transcriptomic analysis to map the secondary metabolism regulatory network of D. styracifolium and identify key transcription factors involved in flavonoid biosynthesis. We then constructed overexpression vectors for the transcription factors and used them to transiently infiltrate Nicotiana benthamiana for functional validation. This experiment confirmed that the transcription factor DsMYB60 promotes the production of total flavonoids in Nicotiana tabacum L. leaves. This study lays the foundation for studying flavonoid biosynthesis in D. styracifolium at the molecular level. Furthermore, this study contributes novel insights into the molecular mechanisms involved in the biosynthesis of active ingredients in medicinal plants.