Chloranthus genome provides insights into the early diversification of angiosperms

AbstractChloranthales remain the last major mesangiosperm lineage without a nuclear genome assembly. We therefore assemble a high-quality chromosome-level genome of Chloranthus spicatus to resolve enigmatic evolutionary relationships, as well as explore patterns of genome evolution among the major lineages of mesangiosperms (eudicots, monocots, magnoliids, Chloranthales, and Ceratophyllales). We find that synteny is highly conserved between genomic regions of Amborella, Vitis, and Chloranthus. We identify an ancient single whole-genome duplication (WGD) (κ) prior to the divergence of extant Chloranthales. Phylogenetic inference shows Chloranthales as sister to magnoliids. Furthermore, our analyses indicate that ancient hybridization may account for the incongruent phylogenetic placement of Chloranthales + magnoliids relative to monocots and eudicots in nuclear and chloroplast trees. Long genes and long introns are found to be prevalent in both Chloranthales and magnoliids compared to other angiosperms. Overall, our findings provide an improved context for understanding mesangiosperm relationships and evolution and contribute a valuable genomic resource for future investigations.

Download Full-text

Chromosome-level genome assembly of Ophiorrhiza pumila reveals the evolution of camptothecin biosynthesis

Nature Communications ◽

10.1038/s41467-020-20508-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Amit Rai ◽

Hideki Hirakawa ◽

Ryo Nakabayashi ◽

Shinji Kikuchi ◽

Koki Hayashi ◽

...

Keyword(s):

Genome Assembly ◽

Whole Genome Duplication ◽

Experimental Validation ◽

Genome Duplication ◽

Indole Alkaloids ◽

Whole Genome ◽

Comparative Genome Analysis ◽

Plant Genomes ◽

Genome Triplication ◽

Chromosome Level

AbstractPlant genomes remain highly fragmented and are often characterized by hundreds to thousands of assembly gaps. Here, we report chromosome-level reference and phased genome assembly of Ophiorrhiza pumila, a camptothecin-producing medicinal plant, through an ordered multi-scaffolding and experimental validation approach. With 21 assembly gaps and a contig N50 of 18.49 Mb, Ophiorrhiza genome is one of the most complete plant genomes assembled to date. We also report 273 nitrogen-containing metabolites, including diverse monoterpene indole alkaloids (MIAs). A comparative genomics approach identifies strictosidine biogenesis as the origin of MIA evolution. The emergence of strictosidine biosynthesis-catalyzing enzymes precede downstream enzymes’ evolution post γ whole-genome triplication, which occurred approximately 110 Mya in O. pumila, and before the whole-genome duplication in Camptotheca acuminata identified here. Combining comparative genome analysis, multi-omics analysis, and metabolic gene-cluster analysis, we propose a working model for MIA evolution, and a pangenome for MIA biosynthesis, which will help in establishing a sustainable supply of camptothecin.

Download Full-text

Molecular insights into the phylogenetic placement of the poorly known genus Niceforonia Goin & Cochran, 1963 (Anura: Brachycephaloidea)

Zootaxa ◽

10.11646/zootaxa.4514.4.3 ◽

2018 ◽

Vol 4514 (4) ◽

pp. 487

Author(s):

ANDRÉS R. ACOSTA-GALVIS ◽

JEFFREY W. STREICHER ◽

LUIGI MANUELLI ◽

TRAVIS CUDDY ◽

RAFAEL O. DE SÁ

Keyword(s):

Phylogenetic Analysis ◽

New World ◽

Taxonomic Revision ◽

Phylogenetic Inference ◽

Genetic Distances ◽

Molecular Phylogenetic Analysis ◽

Phylogenetic Placement ◽

Molecular Phylogenetic ◽

First Time

Among New World direct-developing frogs belonging to the clade Brachycephaloidea (= Terraranae), there are several genera with uncertain phylogenetic placements. One notable example is the genus Niceforonia Goin & Cochran 1963, which includes three species that are endemic to Colombia. Three specimens of the species Niceforonia nana were collected and for the first time the genus is included in a molecular phylogenetic analysis of mitochondrial (mtDNA; 12S and 16S) and nuclear (nucDNA; TYR and RAG1) markers. Molecular phylogenetic inference based on concatenated and separate mtDNA and nucDNA analyses recovered Niceforonia nana nested within Hypodactylus Hedges et al. 2008, rendering the latter genus paraphyletic. Consequently, herein we place the genus Hypodactylus in the synonymy of Niceforonia to resolve the paraphyly and place Niceforonia in the subfamily Hypodactylinae. Based on our revised concept of the genus Niceforonia we conducted preliminary morphological comparisons using specimens and literature descriptions. Finally, Nicefornia nana is quite divergent from other species of Niceforonia (uncorrected genetic distances of ca. 10% 16S and 7% TYR) suggesting that further taxonomic revision may be warranted.

Download Full-text

Chromosome-level genome assembly of the humpback puffer, Tetraodon palembangensis

Gigabyte ◽

10.46471/gigabyte.17 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Rui Zhang ◽

Chang Li ◽

Mengjun Yu ◽

Xiaoyun Huang ◽

Mengqi Zhang ◽

...

Keyword(s):

Southeast Asia ◽

Phylogenetic Tree ◽

Genome Size ◽

Genome Assembly ◽

Teleost Fish ◽

Common Ancestor ◽

Biological Features ◽

Repeat Sequences ◽

Genomic Resource ◽

Chromosome Level

The humpback puffer, Tetraodon palembangensis, is a poisonous freshwater pufferfish species mainly distributed in Southeast Asia (Thailand, Laos, Malaysia and Indonesia). The humpback puffer has many interesting biological features, such as inactivity, tetrodotoxin production and body expansion. Here, we report the first chromosome-level genome assembly of the humpback puffer. The genome size is 362 Mb, with a contig N50 value of ∼1.78 Mb and a scaffold N50 value of ∼15.8 Mb. Based on this genome assembly, ∼61.5 Mb (18.11%) repeat sequences were identified, 19,925 genes were annotated, and the function of 90.01% of these genes could be predicted. Finally, a phylogenetic tree of ten teleost fish species was constructed. This analysis suggests that the humpback puffer and T. nigroviridis share a common ancestor 18.1 million years ago (MYA), and diverged from T. rubripes 45.8 MYA. The humpback puffer genome will be a valuable genomic resource to illustrate possible mechanisms of tetrodotoxin synthesis and tolerance.

Download Full-text

A highly contiguous nuclear genome assembly of the mandarinfish Synchiropus splendidus (Syngnathiformes: Callionymidae)

G3 Genes|Genome|Genetics ◽

10.1093/g3journal/jkab306 ◽

2021 ◽

Author(s):

Martin Stervander ◽

William A Cresko

Keyword(s):

Genome Assembly ◽

Nuclear Genome ◽

Phylogenetic Position ◽

Blue Color ◽

Long Reads ◽

The Family ◽

Commercially Important ◽

Genomic Resource ◽

Genome Assemblies ◽

Important Fish

Abstract The fish order Syngnathiformes has been referred to as a collection of misfit fishes, comprising commercially important fish such as red mullets as well as the highly diverse seahorses, pipefishes, and seadragons—the well-known family Syngnathidae, with their unique adaptations including male pregnancy. Another ornate member of this order is the species mandarinfish. No less than two types of chromatophores have been discovered in the spectacularly colored mandarinfish: the cyanophore (producing blue color) and the dichromatic cyano-erythrophore (producing blue and red). The phylogenetic position of mandarinfish in Syngnathiformes, and their promise of additional genetic discoveries beyond the chromatophores, made mandarinfish an appealing target for whole genome sequencing. We used linked sequences to create synthetic long reads, producing a highly contiguous genome assembly for the mandarinfish. The genome assembly comprises 483 Mbp (longest scaffold 29 Mbp), has an N50 of 12 Mbp, and an L50 of 14 scaffolds. The assembly completeness is also high, with 92.6% complete, 4.4% fragmented, and 2.9% missing out of 4,584 BUSCO genes found in ray-finned fishes. Outside the family Syngnathidae, the mandarinfish represents one of the most contiguous syngnathiform genome assemblies to date. The mandarinfish genomic resource will likely serve as a high-quality outgroup to syngnathid fish, and furthermore for research on the genomic underpinnings of the evolution of novel pigmentation.

Download Full-text

Giant African snail genomes provide insights into molluscan whole-genome duplication and aquatic-terrestrial transition

10.1101/2020.02.02.930693 ◽

2020 ◽

Cited By ~ 2

Author(s):

Conghui Liu ◽

Yuwei Ren ◽

Zaiyuan Li ◽

Qi Hu ◽

Lijuan Yin ◽

...

Keyword(s):

Whole Genome Duplication ◽

Genome Duplication ◽

Terrestrial Ecosystems ◽

Gene Families ◽

Gene Clusters ◽

Immune Defense ◽

Whole Genome ◽

Genomic Plasticity ◽

Ecological Adaptability ◽

Chromosome Level

AbstractWhole-genome duplication (WGD) has been observed across a wide variety of eukaryotic groups, contributing to evolutionary diversity and environmental adaptability. Mollusks are the second largest group of animals, and are among the organisms that have successfully adapted to the nonmarine realm through aquatic-terrestrial (A-T) transition, and no comprehensive research on WGD has been reported in this group. To explore WGD and the A-T transition in Mollusca, we assembled a chromosome-level reference genome for the giant African snail Achatina immaculata, a global invasive species, and compared the genomes of two giant African snails (A. immaculata and Achatina fulica) to the other available mollusk genomes. The chromosome-level macrosynteny, colinearity blocks, Ks peak and Hox gene clusters collectively suggested the occurrence of a WGD event shared by A. immaculata and A. fulica. The estimated timing of this WGD event (∼70 MYA) was close to the speciation age of the Sigmurethra-Orthurethra (within Stylommatophora) lineage and the Cretaceous-Tertiary (K-T) mass extinction, indicating that the WGD reported herein may have been a common event shared by all Sigmurethra-Orthurethra species and could have conferred ecological adaptability and genomic plasticity allowing the survival of the K-T extinction. Based on macrosynteny, we deduced an ancestral karyotype containing 8 conserved clusters for the Gastropoda-Bivalvia lineage. To reveal the mechanism of WGD in shaping adaptability to terrestrial ecosystems, we investigated gene families related to the respiration, aestivation and immune defense of giant African snails. Several mucus-related gene families expanded early in the Stylommatophora lineage, functioning in water retention, immune defense and wound healing. The hemocyanins, PCK and FBP families were doubled and retained after WGD, enhancing the capacity for gas exchange and glucose homeostasis in aestivation. After the WGD, zinc metalloproteinase genes were highly tandemly duplicated to protect tissue against ROS damage. This evidence collectively suggests that although the WGD may not have been the direct driver of the A-T transition, it provided an important legacy for the terrestrial adaptation of the giant African snail.

Download Full-text

RNAs as proximity labeling media for identifying nuclear speckle positions relative to the genome

10.1101/300483 ◽

2018 ◽

Author(s):

Weizhong Chen ◽

Zhangming Yan ◽

Simin Li ◽

Norman Huang ◽

Xuerui Huang ◽

...

Keyword(s):

Rna Splicing ◽

Genomic Sequence ◽

Single Cells ◽

Regulation Of Gene Expression ◽

Nuclear Genome ◽

Fold Increase ◽

Nuclear Speckles ◽

Nuclear Speckle ◽

Interaction Sites ◽

Genomic Regions

AbstractNuclear speckles are interchromatin structures enriched in RNA splicing factors. Determining their relative positions with respect to the folded nuclear genome could provide critical information on co-and post-transcriptional regulation of gene expression. However, it remains challenging to identify which parts of the nuclear genome are in proximity to nuclear speckles, due to physical separation between nuclear speckle cores and chromatin. We hypothesized that noncoding RNAs including small nuclear RNAs, 7SK and Malat1, which accumulate at the periphery of nuclear speckles (nsaRNA,nuclearspeckleassociated RNA), may extend to sufficient proximity to the nuclear genome. Leveraging a transcriptome-genome interaction assay (MARGI), we identified nsaRNA-interacting genomic sequences, which exhibited clustering patterns (nsaPeaks) in the genome, suggesting existence of relatively stable interaction sites for nsaRNAs in nuclear genome. Posttranscriptional pre-mRNAs, which are known to be clustered to nuclear speckles, exhibited proximity to nsaPeaks but rarely to other genomic regions. Furthermore, CDK9 proteins that localize to the vicinity of nuclear speckles produced ChIP-seq peaks that overlapped with nsaPeaks. Our combined DNA FISH and immunofluorescence analysis in 182 single cells revealed a 3-fold increase in odds for nuclear speckles to localize near an nsaPeak than its neighboring genomic sequence. These data suggest a model that nsaRNAs locate in sufficient proximity to nuclear genome and leave identifiable genomic footprints, thus revealing the parts of genome proximal to nuclear speckles.

Download Full-text

Genomic characterization of Vibrio parahaemolyticus from Pacific white shrimp and rearing water in Malaysia reveals novel sequence types and structural variation in genomic regions containing the Photorhabdus insect-related (Pir) toxin-like genes

FEMS Microbiology Letters ◽

10.1093/femsle/fnz211 ◽

2019 ◽

Vol 366 (17) ◽

Cited By ~ 2

Author(s):

Chrystine Zou Yi Yan ◽

Christopher M Austin ◽

Qasim Ayub ◽

Sadequr Rahman ◽

Han Ming Gan

Keyword(s):

Vibrio Parahaemolyticus ◽

Illumina Miseq ◽

Pacific White Shrimp ◽

White Shrimp ◽

Phylogenomic Analysis ◽

Genomic Characterization ◽

Genomic Resource ◽

Acute Hepatopancreatic Necrosis Disease ◽

Genomic Regions

ABSTRACT The Malaysian and global shrimp aquaculture production has been significantly impacted by acute hepatopancreatic necrosis disease (AHPND) typically caused by Vibrio parahaemolyticus harboring the pVA plasmid containing the pirAVp and pirBVp genes, which code for Photorhabdus insect-related (Pir) toxin. The limited genomic resource for V. parahaemolyticus strains from Malaysian aquaculture farms precludes an in-depth understanding of their diversity and evolutionary relationships. In this study, we isolated shrimp-associated and environmental (rearing water) V. parahaemolyticus from three aquaculture farms located in Northern and Central Malaysia followed by whole-genome sequencing of 40 randomly selected isolates on the Illumina MiSeq. Phylogenomic analysis and multilocus sequence typing (MLST) reveal distinct lineages of V. parahaemolyticus that harbor the pirABVp genes. The recovery of pVA plasmid backbone devoid of pirAVp or pirABVp in some V. parahaemolyticus isolates suggests that the toxin genes are prone to deletion. The new insight gained from phylogenomic analysis of Asian V. parahaemolyticus, in addition to the observed genomic instability of pVa plasmid, will have implications for improvements in aquaculture practices to diagnose, treat or limit the impacts of this disease.

Download Full-text

The Taxus genome provides insights into paclitaxel biosynthesis

10.1101/2021.04.29.441981 ◽

2021 ◽

Author(s):

Xingyao Xiong ◽

Junbo Gou ◽

Qinggang Liao ◽

Yanlin Li ◽

Qian Zhou ◽

...

Keyword(s):

Reference Genome ◽

Genome Duplication ◽

Taxus Chinensis ◽

Biosynthesis Pathway ◽

Gene Duplications ◽

Genome Sequences ◽

Biotechnological Potential ◽

Functional Grouping ◽

Transposon Evolution ◽

Chromosome Level

AbstractThe ancient gymnosperm genus Taxus is the exclusive source of the anticancer drug paclitaxel, yet no reference genome sequences are available for comprehensively elucidating the paclitaxel biosynthesis pathway. We have completed a chromosome-level genome of Taxus chinensis var. mairei with a total length of 10.23 Gb. Taxus shared an ancestral whole-genome duplication with the coniferophyte lineage and underwent distinct transposon evolution. We discovered a unique physical and functional grouping of CYP725As (cytochrome P450) in the Taxus genome for paclitaxel biosynthesis. We also identified a gene cluster in the taxadiene biosynthesis, which was mainly formed by gene duplications. This study will facilitate the elucidation of paclitaxel biosynthesis and unleash the biotechnological potential of Taxus.One Sentence SummaryA chromosome-level genome assembly of Taxus chinensis var. mairei uncovers its unique genome evolution process and genetic architectures for the paclitaxel biosynthesis pathway.

Download Full-text

No detectable signal for ongoing genetic recombination in SARS-CoV-2

10.1101/2020.12.15.422866 ◽

2020 ◽

Author(s):

Damien Richard ◽

Christopher J Owen ◽

Lucy van Dorp ◽

François Balloux

Keyword(s):

Genome Assembly ◽

Genetic Recombination ◽

Phylogenetic Reconstruction ◽

Phylogenetic Inference ◽

Genomic Diversity ◽

Viral Agent ◽

Whole Genome ◽

High Quality ◽

Genomic Resource ◽

Inference Methods

The COVID-19 pandemic has led to an unprecedented global sequencing effort of its viral agent SARS-CoV-2. The first whole genome assembly of SARS-CoV-2 was published on January 5 2020. Since then, over 150,000 high-quality SARS-CoV-2 genomes have been made available. This large genomic resource has allowed tracing of the emergence and spread of mutations and phylogenetic reconstruction of SARS-CoV-2 lineages in near real time. Though, whether SARS-CoV-2 undergoes genetic recombination has been largely overlooked to date. Recombination-mediated rearrangement of variants that arose independently can be of major evolutionary importance. Moreover, the absence of recombination is a key assumption behind the application of phylogenetic inference methods. Here, we analyse the extant genomic diversity of SARS-CoV-2 and show that, to date, there is no detectable hallmark of recombination. We assess our detection power using simulations and validate our method on the related MERS-CoV for which we report evidence for widespread genetic recombination.

Download Full-text

SNAPPy: A snakemake pipeline for scalable HIV-1 subtyping by phylogenetic pairing

Virus Evolution ◽

10.1093/ve/vez050 ◽

2019 ◽

Vol 5 (2) ◽

Author(s):

Pedro M M Araújo ◽

Joana S Martins ◽

Nuno S Osório

Keyword(s):

Immune Evasion ◽

Large Scale ◽

Phylogenetic Inference ◽

Therapeutic Outcomes ◽

Immunodeficiency Virus ◽

Protection Legislation ◽

Genomic Regions ◽

Hiv 1 ◽

Human Immunodeficiency Virus 1 ◽

Scale Sequence

Abstract Human immunodeficiency virus 1 (HIV-1) genome sequencing is routinely done for drug resistance monitoring in hospitals worldwide. Subtyping these extensive datasets of HIV-1 sequences is a critical first step in molecular epidemiology and evolution studies. The clinical relevance of HIV-1 subtypes is increasingly recognized. Several studies suggest subtype-related differences in disease progression, transmission route efficiency, immune evasion, and even therapeutic outcomes. HIV-1 subtyping is mainly done using web-servers. These tools have limitations in scalability and potential noncompliance with data protection legislation. Thus, the aim of this work was to develop an efficient method for large-scale local HIV-1 subtyping. We designed SNAPPy: a snakemake pipeline for scalable HIV-1 subtyping by phylogenetic pairing. It contains several tasks of phylogenetic inference and BLAST queries, which can be executed sequentially or in parallel, taking advantage of multiple-core processing units. Although it was built for subtyping, SNAPPy is also useful to perform extensive HIV-1 alignments. This tool facilitates large-scale sequence-based HIV-1 research by providing a local, resource efficient and scalable alternative for HIV-1 subtyping. It is capable of analyzing full-length genomes or partial HIV-1 genomic regions (GAG, POL, and ENV) and recognizes more than ninety circulating recombinant forms. SNAPPy is freely available at: https://github.com/PMMAraujo/snappy/releases.

Download Full-text