Search bioRxiv⌕ Search

SEARCH · Search bioRxiv

Results for “genomics”

Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
bioRxiv2024

Haplotype-resolved genomes provide insights into the origin and function of genome diversity in bivalves

Bivalves are famed for exhibiting vast genetic diversity of poorly understood origins and functional significance. Within bivalves, oysters are an ancient group showing remarkable genetic and phenotypic variability alongside extensive adaptability, serving as an ideal system to understand the origins and functional significance of genomic diversity. Here, we reveal the divergent genomic landscape of Crassostrea oysters, characterized by a history of genome size reduction associated with transposable elements (TEs). By constructing a haplotype-resolved genome for Kumamoto oyster C. sikamea, we demonstrate the widespread presence of haplotype divergent sequences (HDS); genomic regions present in just one haplotype. Combined with population resequencing, we define the role of genomic divergence driven by TEs in shaping oyster genetic diversity. Comparisons of haplotype-resolved genomes across four bivalve orders reveal that while extensive HDS is common, its origins may differ markedly. We show that HDS are a hotspot of genetic innovation, harboring rapidly evolving genes of various evolutionary ages, while also strongly influencing gene expression phenotypes. A widespread lack of allele-specific expression shared among oyster individuals indicates that haplotype polymorphism provides a key source of expression variation, promoting phenotypic plasticity and adaptation. These findings advance understanding on the origins of genomic diversity and its role in adaptive evolution.

genomics↗
bioRxiv2025

A high-quality reference genome for the Ural Owl (Strix uralensis) enables investigations of cell cultures as a genomic resource for endangered species

BackgroundReference genomes have a wide range of applications. Yet, we are from a complete genomic picture for the tree of life. We here contribute another piece to the puzzle by providing a high-quality reference genome for the Ural Owl (Strix uralensis), a species of conservation concern and efforts affected by habitat destruction and climate change. ResultsWe generated a reference genome assembly for the Ural Owl based on high-fidelity (HiFi) long reads and chromosome conformation capture (Hi-C) data. It figures amongst the best avian genome assemblies currently available (BUSCO completeness of 99.94 %). The primary assembly had a size of 1.38 Gb with a scaffold N50 of 90.1 Mb, while the alternative assembly had a size of 1.3 Gb and a scaffold N50 of 17.0 Mb. We show an exceptionally high repeat content (21.07 %) that is different from those of other bird taxa with repeat extensions. We confirm a Strix characteristic chromosomal fusion and support the observation that bird microchromosomes have a higher density of genes, associated with a reduction in gene length due to shorter introns. An analysis of gene content provides evidence of changes in the keratin gene repertoire as well as modifications of metabolism genes of owls. This opens an avenue of research if this is related to flight adaptations. The population size history of the Ural Owl decreased over long periods of time with increases during the Eemian interglacial and stable size during the last glacial period. Ever since it is declining to its currently lowest effective population size. We also investigated cell culture of progressive passages as a tool for genetic resources. Karyotyping of passages confirmed no large variants, while a SNP analysis revealed a low presence of short variants across cell passages. ConclusionsThe established reference genome is a valuable resource for ongoing conservation efforts, but also for (avian) comparative genomics research. Further research is needed to determine whether cell culture passages can be safely used in genomic research.

genomics↗
bioRxiv2025

Genomic Characterization of Novel Endophyte Strains from Tall Fescue Shows Genome Fragmentation Post-Hybridization

Interspecific hybridization in fungi has gained attention for its role in fungal evolution and potential commercial applications. Successful hybridization can enhance fitness and facilitate adaptation to new ecological niches. However, the genomic consequences of hybridization in fungi remain poorly understood. Epichloe is a genus of fungi that includes both non-hybrid and hybrid species, with the hybrids forming through parasexual hybridization and reproducing asexually. Some Epichloe hybrids are of commercial significance, as they colonize Lolium arundinaceum (Schreb.) Darbysh., a crucial forage and turf grass species. In this study, we sought to generate high-quality genome assemblies for two previously uncharacterized Epichloe hybrid strains, both of which are similar to Epichloe sp. FaTG-3. We aimed to characterize their genomes and examine the effects of parasexual interspecific hybridization on fungal genome structure. Our results reveal that the genomes of both strains are rich in AT-rich blocks and repetitive elements. Upon comparison with putative progenitor genomes, we observed significant fragmentation and rearrangement. Despite the genomic instability, more than 85% of gene homologs from each progenitor species were retained. This study demonstrates that while parasexual hybridization dramatically alters genome structure, it does not significantly affect gene content.

genomics↗
bioRxiv2025

Genome Report: Improved chromosome-level genome assembly of the American cockroach, Periplaneta americana

1The American cockroach, Periplaneta americana, is a cosmopolitan insect notorious for thriving among humans undeterred by attempts to eliminate it. The traits that contribute to its ubiquity as an opportunistic pest, such as long lifespan, expansive neurosensory capacity, and nutritional flexibility, also make P. americana an excellent invertebrate model organism with a long history in neuroscience and physiological research. Current genetic resources available for P. americana highlight its large, complex genome and richly diverse transcriptional capabilities, but fall short of producing a complete, chromosome-level genome. Here, we present a high-quality de novo genome assembly of a laboratory-raised adult female P. americana using a combination of high fidelity PacBio long reads and Hi-C sequencing. The final 3.23 Gb genome was assembled with chromosomal resolution into 17 scaffolds, consistent with previous karyotype analysis, and has a scaffold N50 of 188.1 Mb and genome BUSCO score of 99.7%. This assembly includes a chromosome that was missing from the previous reference genome for this species. Protein prediction and annotation were performed via the NCBI Eukaryotic Genome Annotation Pipeline, which identified 16,780 protein-coding genes and generated an annotation BUSCO score of 97.8%. Ortholog comparisons with available Blattodea assemblies highlight the expanded chemosensory and immune capabilities of P. americana compared to termite relatives. This genome assembly is a valuable tool for facilitating future research on the biology and evolution of this remarkable insect.

genomics↗
bioRxiv2025

Whole-genome sequence of Potamopyrgus antipodarum: a model system for the maintenance of sexual reproduction reveals a recent whole-genome duplication

Key unanswered questions in biology center on the causes, consequences, and maintenance of sexual reproduction ("sex"). Genome-driven processes are central to the evolutionary and genetic mechanisms inherent to sex, making genomic resources a fundamental part of answering these questions. We present the first genome assembly for a species that is uniquely well-suited for the study of (a)sex in nature, Potamopyrgus antipodarum. This New Zealand snail is unusual in featuring multiple separate transitions from obligately sexual to obligately asexual reproduction, leading to the coexistence of phenotypically similar sexual and asexual forms, a feature that is required to directly study the maintenance of sex. These separately derived asexual lineages constitute separate evolutionary experiments, providing a powerful means of characterizing how the absence of sex affects genome evolution. Our genome assembly provides critical steps towards understanding causes and consequences of sex in this system and important resources for the rapidly growing P. antipodarum and molluscan genomics research community. In characterizing this genome, we uncovered unexpected evidence for a recent whole-genome duplication (WGD) in P. antipodarum. This discovery sets the stage for using P. antipodarum to evaluate processes of rediploidization following WGD and assess whether WGD might drive transitions to asexuality.

genomics↗
bioRxiv2025

The genome of the early diverged amphioxus, Asymmetron lucayanum, illuminates the evolution of genome architecture and gene repertoires in cephalochordates

Cephalochordates (amphioxus or lancelet) are considered as living proxies for ancestral chordates due to their key phylogenetic position and slow evolutionary rate. The genomes of living amphioxus thus can help to reveal the genetic basis shaping the evolutionary transition from invertebrates to vertebrates. To gain a comprehensive understanding of the genome architecture in amphioxus, here we generate a chromosome-anchored genome assembly for Asymmetron lucaynum, representing the earliest diverging cephalochordate genus. Our results show that Asymmetron has an enlarged genome compared to those of the other four cephalochordate genomes decoded so far (all in the genus Branchiostoma), causing by pervasive expansions of inter-genic transposable elements (TEs). Nevertheless, both macrosynteny and microsynteny remain highly conserved between Asymmetron and Branchiostoma, enabling reconstruction of the ancestral genomic architecture of the Cephalochordate lineage for tracing genome evolutionary process during Deuterostome and Chordate diversification. By coupling developmental transcriptomic analyses, we further show that purifying selection and constraints on co-transcriptional regulation may have contributed to the maintenance of the conserved microsynteny blocks among cephalochordate species. We also examine the evolutionary history of Hox cluster in cephalochordates and vertebrates, and identify species-specific inversions and TE invasions at this important locus in both Asymmetron and Branchiostoma. Finally, we survey key gene families involved in both innate and adaptive immunity (e.g., TLR, NLR, MHC, and RAG) and uncover their plausible ancestry and evolutionary dynamics in chordates. Taken together, our findings illuminate the genome and gene evolution of cephalochordates and provide valuable resources for understanding the early evolution of chordates and the origin of vertebrates.

genomics↗
bioRxiv2025

Phylogenetic placement and contamination screening of Amoebozoa genomic data from the Protist 10,000 Genomes (P10K) Database

BackgroundGenomic data are essential for uncovering the evolutionary history, ecological roles, and diversity of life. Yet, diverse microbial eukaryotes, predominantly unicellular and traditionally referred to as protists, remain critically underrepresented in genomic repositories, limiting our ability to address fundamental questions in eukaryotic evolution. The Protist 10,000 Genomes (P10K) initiative seeks to fill this gap by generating and compiling genomic and transcriptomic data for a wide range of microbial eukaryotes. However, large-scale sequencing efforts face persistent challenges, including contamination and imprecise taxonomic identification, particularly for poorly studied taxa that require specialized taxonomic expertise. To ensure the reliability of these resources, robust and scalable approaches for taxonomic identification and contamination screening are essential. ResultsWe developed CSI-SSU (https://github.com/AlexTiceLab/CSI-SSU), a command-line tool for Contaminant Sequence Investigation (CSI) that uses small subunit ribosomal RNA (SSU) sequences, chimeric sequence detection, and phylogenetic placement to rapidly identify, retrieve, and classify SSU sequences from eukaryotic genomic-level assemblies. CSI-SSU incorporates a curated SSU reference dataset representing the major known eukaryotic supergroups, with sequences and taxonomic nomenclature derived from the Protist Ribosomal Reference (PR2) database. In addition to detecting contaminant sequences, CSI-SSU enables approximate taxonomic assignment of the target lineage in each assembly, with resolution constrained by the current diversity represented in PR2. To further assess potential bacterial contamination, CSI-SSU employs bacterial BUSCO searches as a proxy. We demonstrate CSI-SSU utility and performance by screening 2,960 genomic-level assemblies spanning a broad diversity of eukaryotes from P10K. CSI-SSU efficiently detected non-target eukaryotic SSU sequences, revealing cross-group contamination. Classifications also corroborated or refined the original taxonomic assignments, with resolution depending on PR2 representation. Bacterial BUSCO searches indicated bacterial contamination. Independent SSU and COI phylogenies of Amoebozoa supported CSI-SSU classifications, highlighting its accuracy and sensitivity. ConclusionCSI-SSU provides a scalable and reproducible framework for phylogenetically informed contamination screening and taxonomic validation of genomic and transcriptomic data. Coupling phylogenetic placement with contamination detection enabled us to distinguish high-quality P10K datasets from those requiring decontamination or additional sequencing before downstream use. These findings serve as a reference for future analyses and guide further sequencing efforts to expand the taxonomic diversity of microbial eukaryotes at the genomic level. Addressing imprecise taxonomic assignments, contamination, and reproducibility in genomic-level datasets will enhance the value of these resources and facilitate studies illuminating the evolution and diversification of eukaryotic life.

genomics↗
bioRxiv2018

Fine-scale characterization of genomic structural variation in the human genome reveals adaptive and biomedically relevant hotspots

Genomic structural variants (SVs) are distributed nonrandomly across the human genome. These \"hotspots\" have been implicated in critical evolutionary innovations, as well as serious medical conditions. However, the evolutionary and biomedical features of these hotspots remain incompletely understood. In this study, we analyzed data from 2,504 genomes from the 1000 Genomes Project Consortium and constructed a refined map of 1,148 SV hotspots in human genomes. By studying the genomic architecture of these hotspots, we found that both nonallelic homologous recombination and non-homologous mechanisms act as mechanistic drivers of SV formation. We found that the majority of SV hotspots are within gene-poor regions and evolve under relaxed negative selection or neutrality. However, we found that a small subset of SV hotspots harbor genes that are enriched for anthropologically crucial functions, including blood oxygen transport, olfaction, synapse assembly, and antigen binding. We provide evidence that balancing selection may have maintained these SV hotspots, which include two independent hotspots on different chromosomes affecting alpha and beta hemoglobin gene clusters. Biomedically, we found that the SV hotspots coincide with breakpoints of clinically relevant, large de novo SVs, significantly more often than genome-wide expectations. As an example, we showed that the breakpoints of multiple large de novo SVs, which lead to idiopathic short stature, coincide with SV hotspots. As such, the mutational instability in SV hotpots likely enables chromosomal breaks that lead to pathogenic structural variation formations. Our study contributes to a better understanding of the mutational landscape of the genome and implicates both mechanistic and adaptive forces in the formation and maintenance of SV hotspots.

genomics↗
bioRxiv2018

High coverage genome sequencing and identification of genomic variants in Bengal tiger (Panthera tigris tigris)

Bengal tiger (Panthera tigris tigris), one of six extant tiger subspecies, occurs solely in the Indian subcontinent. Although endangered and threatened by various extinction risks, this is the most populous tiger subspecies with the highest genetic diversity and strongest chance of survival in the wild. Availability of high quality genomic information on this animal will help us understand its ability to adapt to different habitats and environmental changes, in addition to comparative studies with other subspecies. Here we report high coverage sequencing of the Bengal tiger genome and its mapping to the Amur tiger genome in order to discover single nucleotide to large structural variants. A total of 345 Gb, roughly equivalent to 144X coverage of the genome, was generated from 1,149,381,669 raw read pairs. Further, 990,060,729 clean read pairs, again equivalent to 115X coverage, were retained from the raw read data and considered for comparative analysis with the Amur tiger genome. This alignment showed that 97.35% of the bases mapped at 5X depth, 97.26% at 10X and 90.44% at 50X depth. We identified a total of 3,601,882 single nucleotide variants, 948 structural variants, 56,649 copy number variants and 1,760,347 simple sequence repeats. We report the first high coverage genome sequence of Bengal tiger with an overview of its genomic variants when compared to the Amur tiger genome. Of the several variants identified, we further have to assess and validate variants potentially associated with the ability of the animal to adapt to environmental changes, disease susceptibility and other important biological phenomena.

genomics↗
bioRxiv2025

Caenorhabditis briggsae ancestral genomic hyper-diversity contrasts with globally distributed genome-wide haplotypes

Comparative genomics provides a powerful framework to uncover the molecular and evolutionary mechanisms that shape genetic diversity within and across species, revealing how shared and lineage-specific processes influence their evolutionary trajectories through time. The nematode Caenorhabditis briggsae is distributed world-wide and is a comparative model to Caenorhabditis elegans in the biology of development, cellular mechanisms, neurobiology, genetic mappings of complex traits, and genome evolution. Following massive collection efforts by the nematode research community, we present the isolation of over 2,000 wild strains and analyses of genome sequences that catalog over six million single-nucleotide and insertion-deletion variants. This genome and strain resource provide a powerful means to interrogate the causal genetic bases of phenotypic variation for diverse traits. Additionally, we describe its global population structure and discover new and genetically distinct groups within this primarily self-fertilizing species, including groups of highly related strains that were sampled across different continents. We leverage expansive genetic variation to decipher the effects of linkage and selection on the distribution of genetic diversity across the genome and across geographic regions. Within the species, we find genomic regions with extremely high levels of genetic variation similar to hyper-divergent regions found in C. elegans and other species. These regions harbor new genes and variation enriched for environmental sensing and pathogen responses. In comparison to the outbreeding sister species Caenorhabditis nigoni, we conclude that long-term balancing selection has maintained substantial functional variation since the divergence from their outbreeding ancestor, likely in response to differences in the ecological niche. Overall, this massive strain resource enables future comparative genetics and genomics studies, including genome-wide association studies between Caenorhabditis species.

genomics↗
bioRxiv2026

Functional In-Context Learning in Genomic Language Models with Nucleotide-Level Supervision and Genome Compression

AO_SCPLOWBSTRACTC_SCPLOWGenomic foundation models aim to learn general-purpose representations directly from DNA sequence, enabling sequence understanding, generation, and probabilistic reasoning across a wide range of biological tasks. Scaling such models to genomic lengths, however, remains challenging due to the tension between long-range context, nucleotide-level resolution, and practical computational efficiency. Architectural innovations have enabled increasingly long nominal inputs, but often struggle to translate additional context into meaningful performance gains, particularly in the presence of sparse functional signal along eukaryotic genomes. In this work, we revisit the design of long-context genomic foundation models from the perspective of training objective and data construction. We introduce Factorized Nucleotide Supervision (FNS), which reconciles efficient k-mer tokenization with single-nucleotide likelihoods through probability marginalization, and Genome Compression Pretraining (GCP), which reshapes the training distribution by concentrating on gene-centric and regulatory regions. Together, these techniques enable standard transformer-based models to perform functional in-context learning without sacrificing nucleotide-level fidelity or computational efficiency. Building on these ideas, we present a family of autoregressive genomic foundation models supporting contexts of up to 98k base pairs across eukaryotic and prokaryotic genomes. Across training-free evaluations and downstream fine-tuning benchmarks, our models consistently improve over prior approaches and match or exceed state-of-the-art baselines while enabling substantially more efficient inference. Together, these results demonstrate that aligning supervision and data regimes with the biological structure of genomic sequence provides a principled and effective path toward scalable and biologically faithful genomic language modeling. Models, data, and scripts for downstream analyses are publicly available at https://huggingface.co/GenerTeam.

genomics↗
bioRxiv2026

Chromosome-scale genome assemblies of duckweeds provide insights into genomic plasticity, aquatic adaptation and morphological reduction

BackgroundDuckweeds (Lemnaceae) present a striking example of convergent genome evolution following the return from land to water. As the smallest and fastest-growing angiosperms, they exhibit extreme morphological reduction yet retain remarkable genomic plasticity through recurrent interspecific hybridisation, chromosomal rearrangements, and selective gene-family remodelling. The genomic mechanisms that distinguish this secondarily aquatic lifestyle from terrestrial ancestors, and whether these changes are convergent with other aquatic lineages such as seagrasses, have remained incompletely resolved. ResultsHere we report chromosome-scale genome assemblies for four duckweed species, Spirodela polyrhiza, Lemna minuta, Lemna japonica, and Lemna aequinoctialis, generated with PacBio HiFi long reads and Omni-C chromatin conformation capture. These assemblies include the first genomic characterisation of an unresolved hybrid lineage (L. aequinoctialis x) that harbours a previously uncharacterised 3.5 Mb reciprocal translocation between subgenomes, as well as confirmation of the allodiploid origin of L. japonica. Comparative phylogenomics with land plants and the seagrass Zostera marina reveals a coherent, non-random programme of gene loss: effector-triggered immunity (ETI) components (EDS1 and PAD4) and the high-affinity nitrate transporter NRT2 are convergently absent across duckweeds and Zostera marina, consistent with relaxed pathogen pressure and abundant dissolved nutrients in aquatic habitats. In contrast, secondary-metabolite biosynthesis pathways for flavonoids, anthocyanins, flavones and flavonols are retained or expanded despite overall genome compaction. ConclusionThese findings illustrate how the return to aquatic environments following terrestrialisation shaped duckweed genome evolution through convergent gene loss and selective pathway retention, and provide high-quality genomic resources to support future research in plant evolutionary biology and biotechnology.

genomics↗
bioRxiv2016

EuMicrobedbLite: A lightweight genomic resource and analytic platform for draft oomycete genomes

We have developed EuMicrobedbLite - A light weight comprehensive genome resource and sequence analysis platform for oomycete organisms. EuMicrobedbLite is a successor of the VBI Microbial Database (VMD) that was built using the Genome Unified Schema (GUS). In this version, the GUS schema has been greatly simplified with removal of many obsolete modules and redesign of others to incorporate contemporary data. Several dependencies such as perl object layers used for data loading in VMD have been replaced with independent light weight scripts. EumicrobedbLite now runs on a powerful annotation engine developed at our lab called \"Genome Annotator Lite\". Currently this database has 26 publicly available genomes and 10 EST datasets of oomycete organisms. The browser page has dynamic tracks presenting comparative genomics analyses, coding and non-coding data, tRNA genes, repeats and EST alignments. In addition, we have defined 44,777 core conserved proteins from twelve oomycete organisms that form 2974 clusters. Synteny viewing is enabled by incorporation of the Genome Synteny Viewer (GSV) tool. The user interface has undergone major changes for ease of browsing. Queryable comparative genomics information, conserved orthologous genes and pathways are among the new key features updated in this database. The browser has been upgraded to enable user upload of GFF files for quick view of genome annotation comparisons. The toolkit page integrates the EMBOSS package and has a gene prediction tool. Annotations for the organisms are updated once every six months to ensure quality. The database resource is available at www.eumicrobedb.org.

bioinformatics↗
bioRxiv2017

Comparative Genomics Of Apomictic Root-Knot Nematodes: Hybridization, Ploidy, And Dynamic Genome Change

The Root-Knot Nematodes (RKN; genus Meloidogyne) are important plant parasites causing substantial agricultural losses. The Meloidogyne incognita group (MIG) of species, most of which are obligatory apomicts (mitotic parthenogens), are extremely polyphagous and important problems for global agriculture. While understanding the genomic basis for their variable success on different crops could benefit future agriculture, analyses of their genomes pose challenges due to complex evolutionary histories that may incorporate hybridization, ploidy changes, and chromosomal fragmentation. Here we sequence 19 genomes, representing five species of key RKN collected from different geographic origins. We show that a hybrid origin that predated speciation within the MIG has resulted in each species possessing two divergent genomic copies. Additionally, the MIG apomicts are hypotriploids, with a proportion of one genome present in a second copy, and this proportion varies among species. The evolutionary history of the MIG genomes is revealed to be very dynamic, with non-crossover recombination both homogenising the genomic copies, and acting as a mechanism for generating divergence between species. Interestingly, the automictic MIG species M. floridensis differs from the apomict species in that it has become homozygous throughout much of its genome.

evolutionary biology↗
bioRxiv2017

Genome-Wide Comparison Of Toxigenic And Non-Toxigenic Corynebacterium diphtheriae Isolates Identifies Differences In The Pan Genomes Between Respiratory And Cutaneous Strains

ObjectivesCorynebacterium diphtheriae is the main etiological agent of diphtheria, a global disease causing life-threatening infections, particularly in infants and children. Vaccination with diphtheria toxoid protects against infection with potent toxin producing strains. However a growing number of apparently non-toxigenic but potentially invasive C. diphtheriae strains are identified in countries with low prevalence of diphtheria, raising key questions about genomic structures and population dynamics of the species.\n\nMethodsThis study examined genomic diversity among 47 C. diphtheriae isolates collected in Australia over a 10-year period using whole genome sequencing. Phylogeny was determined using SNP-based mapping and genome wide analysis.\n\nResultsC. diphtheriae sequence type (ST) 32, a non-toxigenic ST with evidence of enhanced virulence that is also circulating in Europe, appears to be endemic in Australia. Isolates from temporospatially related patients displayed the same ST and similarity in their core genomes. The genome-wide analysis highlighted a role of pilins, adhesion factors and iron utilization in infections caused by toxigenic as well as non-toxigenic strains.\n\nConclusionsThe genomic diversity of toxigenic and non-toxigenic strains of C. diphtheriae in Australia suggests multiple local and overseas sources of infection and colonisation. Our findings suggest that regular genomic surveillance of co-circulating toxigenic and non-toxigenic C. diphtheriae can deliver highly nuanced data in order to inform targeted public health actions and policy for predicting the future impact of this highly successful pathogen.

microbiology↗
bioRxiv2020

Genomic novelty versus convergence in the basis of adaptation to whole genome duplication

Whole genome duplication (WGD) occurs across kingdoms and can promote adaptation. However, a sudden increase in chromosome number, as well as changes in physiology, are traumatic to conserved processes. Previous work in Arabidopsis arenosa revealed a coordinated genomic response to WGD, involving physically interacting meiosis proteins, as well as changes related to cell cycle and ion homeostasis. Here we ask: is this coordinated shift in the same processes repeated in another species following WGD? To answer this, we resequenced and cytologically assessed replicated populations from a diploid/autotetraploid system, Cardamine amara, and test the hypothesis that gene and process-level convergence will be prevalent between these two WGDs adaptation events. Interestingly, we find that gene-level convergence is negligible, with no more in common than would be expected by chance. This was most clear at meiosis-related genes, consistent with our cytological assessment of somewhat lower meiotic stability in C. amara, despite establishment and broad occurrence of the autotetraploid in nature. In contrast, obvious convergence at the level of functional processes, including meiotic cell cycle, chromosome organisation and stress signalling was evident. This indicates that the two autotetraploids survived challenges attendant to WGD via contrasting solutions, modifying different players from similar processes. Overall, this work gives the first insight into the salient adaptations required to cope with a genome-doubled state and brings the first genomic evidence that autopolyploids can utilize multiple trajectories to achieve adaptation to WGD. We speculate that this flexibility increases the likelihood a nascent polyploid overcomes early stringent challenges to later access the spectrum of evolutionary opportunities of polyploidy. Significance statementWhole genome duplication (WGD) is a tremendous mutation and an important evolutionary force. It also presents immediate changes to meiosis and cell physiology that nascent polyploids must overcome to survive. Given the dual facts that WGD adaptation is difficult, but many lineages nevertheless survive WGD, we ask: how constrained are the evolutionary responses to a genome-doubled state? We previously identified candidate genes for WGD adaptation in Arabidopsis arenosa, which has natural diploid and tetraploid variants. Here we test for evolutionary convergence in adaptation to WGD in a species 17 million years distant, Cardamine amara. This work gives the first genomic insight into of how autopolyploids utilize multiple adaptive trajectories to manage a genome-doubled state.

evolutionary biology↗
bioRxiv2020

Comparative analyses of SAR-CoV2 genomes from different geographical locations and other coronavirus family genomes reveals unique features potentially consequential to host-virus interaction and pathogenesis

The ongoing pandemic of the coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). We have performed an integrated sequence-based analysis of SARS-CoV2 genomes from different geographical locations in order to identify its unique features absent in SARS-CoV and other related coronavirus family genomes, conferring unique infection, facilitation of transmission, virulence and immunogenic features to the virus. The phylogeny of the genomes yields some interesting results. Systematic gene level mutational analysis of the genomes has enabled us to identify several unique features of the SARS-CoV2 genome, which includes a unique mutation in the spike surface glycoprotein (A930V (24351C>T)) in the Indian SARS-CoV2, absent in other strains studied here. We have also predicted the impact of the mutations in the spike glycoprotein function and stability, using computational approach. To gain further insights into host responses to viral infection, we predict that antiviral host-miRNAs may be controlling the viral pathogenesis. Our analysis reveals nine host miRNAs which can potentially target SARS-CoV2 genes. Interestingly, the nine miRNAs do not have targets in SARS and MERS genomes. Also, hsa-miR-27b is the only unique miRNA which has a target gene in the Indian SARS-CoV2 genome. We also predicted immune epitopes in the genomes

bioinformatics↗
bioRxiv2020

Reanalysis of Genome Sequences of tomato accessions and its wild relatives: Development of tomato genomic variation (TGV) database integrating SNPs and INDELs polymorphisms

MotivationFacilitated by technological advances and expeditious decrease in the sequencing costs, whole-genome sequencing (WGS) is increasingly implemented to uncover variations in cultivars/accessions of many crop plants. In tomato (Solanum lycopersicum), the availability of the genome sequence, followed by the resequencing of tomato cultivars and its wild relatives, has provided a prodigious resource for the improvement of traits. A high-quality genome resequencing of 84 tomato accessions and wild relatives generated a dataset that can be used as a resource to identify agronomically important alleles across the genome. Converting this dataset into a searchable database, including information about the influence of SNPs on protein function, provides valuable information about the genetic variations. The database will assist in searching for functional variants of a gene for introgression into tomato cultivars. ResultsA recent release of better-quality tomato genome reference assembly SL3.0, and new annotation ITAG3.2 of SL3.0, dropped 3,857 genes, added 4,900 novel genes, and updated 20,766 genes. Using the above version, we remapped the data from the tomato lines resequenced under the "100 Tomato Genome ReSequencing Project" on new tomato genome assembly SL3.0 and made an online searchable Tomato Genomic Variations (TGV) database. The TGV contains information about SNPs and InDels and expands it by functional annotation of variants with new ITAG3.2 using SIFT4G software. This database with search function assists in inferring the influence of SNPs on the function of a target gene. This database can be used for selecting SNPs, which can be potentially deployed for improving tomato traits. Availability and ImplementationTGV is freely available at http://psd.uohyd.ac.in/tgv. Contactrameshwar.sharma@gmail.com

bioinformatics↗