scholarly journals A new Spirodela polyrhiza genome and proteome reveal a conserved chromosomal structure with high abundances of proteins favoring energy production

Author(s):  
Alex Harkess ◽  
Fionn McLoughlin ◽  
Natasha Bilkey ◽  
Kiona Elliott ◽  
Ryan Emenecker ◽  
...  

AbstractDuckweeds are a monophyletic group of rapidly reproducing aquatic monocots in the Lemnaceae family. Spirodela polyrhiza, the Greater Duckweed, has the largest body plan yet the smallest genome size in the family (1C = 150 Mb). Given their clonal, exponentially fast reproduction, a key question is whether genome structure is conserved across the species in the absence of meiotic recombination. We generated a highly contiguous, chromosome-scale assembly of Spirodela polyrhiza line Sp7498 using Oxford Nanopore plus Hi-C scaffolding (Sp7498_HiC) which is highly syntenic with a related line (Sp9509). Both the Sp7498_HiC and Sp9509 genome assemblies reveal large chromosomal misorientations in a recent PacBio assembly of Sp7498, highlighting the necessity of orthogonal long-range scaffolding techniques like Hi-C and BioNano optical mapping. Shotgun proteomics of Sp7498 verified the expression of ∼2,250 proteins and revealed a high abundance of proteins involved in photosynthesis and carbohydrate metabolism among other functions. In addition, a strong increase in chloroplast proteins was observed that correlated to chloroplast density. This Sp7498_HiC genome was generated cheaply and quickly with a single Oxford Nanopore MinION flow cell and one Hi-C library in a classroom setting. Combining these data with a mass spectrometry-generated proteome illustrates the utility of duckweed as a model for genomics- and proteomics-based education.

Author(s):  
Alex Harkess ◽  
Fionn McLoughlin ◽  
Natasha Bilkey ◽  
Kiona Elliott ◽  
Ryan Emenecker ◽  
...  

Abstract Duckweeds are a monophyletic group of rapidly reproducing aquatic monocots in the Lemnaceae family. Given their clonal, exponentially fast reproduction, a key question is whether genome structure is conserved across the species in the absence of meiotic recombination. Here, we studied the genome and proteome of Spirodela polyrhiza, or Greater Duckweed, which has the largest body plan yet the smallest genome size in the family (1C = 150 Mb). Using Oxford Nanopore sequencing combined with Hi-C scaffolding, we generated a highly contiguous, chromosome-scale assembly of S. polyrhiza line Sp7498 (Sp7498_HiC). Both the Sp7498_HiC and Sp9509 genome assemblies reveal large chromosomal misorientations relative to a recent PacBio assembly of Sp7498, highlighting the need for orthogonal long-range scaffolding techniques such as Hi-C and BioNano optical mapping. Shotgun proteomics of Sp7498 verified the expression of ~2,250 proteins and revealed a high abundance of proteins involved in photosynthesis and carbohydrate metabolism among other functions. In addition, a strong increase in chloroplast proteins was observed that correlated to chloroplast density. This Sp7498_HiC genome was generated cheaply and quickly with a single Oxford Nanopore MinION flow cell and one Hi-C library in a classroom setting. Combining these data with a mass spectrometry-generated proteome illustrates the utility of duckweed as a model for genomics- and proteomics-based education.


Coronaviruses ◽  
2020 ◽  
Vol 01 ◽  
Author(s):  
Poonam B ◽  
Prabhjot Kaur Gill

Background: The positive sense and inordinate large RNA genome are enclosed by helical nuceocapsids along with an outermost layer belongs to the family Coronaviridae. The phylogenetic tree of this family has been quartered into Class1 as alpha, Class 2 as beta, Class 3 as gamma and Class 4 as delta CoV. The mammalian respiratory and gastrointestinal tracts are the main target organs of this enveloped virus with misperceived mechanisms. The relevance of this virus family has considerably increased by the dint of recent emergence of the Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS), which are caused by viruses belonging to the beta-CoV group. Aim: Aforesaid illustrations of emergence of coronavirus diseases over the past two decades, SARS (2002 and 2003) and MERS (2012 to present) - the ongoing COVID-19 outbreak has pressurized the WHO to take innovative measures for public health, research and medical communities. The aim of the present review is to have proficiency in coronavirus replication and transcription process which is still in its infancy. Conclusion: An outcome of epidemics, it is being recognized as one of the most advancing viruses by the virtue of high genomic nucleotide substitution rates and recombination. The hallmark of coronavirus replication is discontinuous transcription resulting in the production of multiple subgenomic mRNAs having sequences complementary to both ends of the genome. Therefore, complete genome sequence of coronavirus will be used as frame of reference for knowing this classical phenomenon of RNA replication process. Finally, research on the pathogenesis of coronaviruses and the host immunopathological response will aid in designing vaccines and minimizing mortality rate.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
John W Davey ◽  
Carolina M C Catta-Preta ◽  
Sally James ◽  
Sarah Forrester ◽  
Maria Cristina M Motta ◽  
...  

Abstract Angomonas deanei is an endosymbiont-bearing trypanosomatid with several highly fragmented genome assemblies and unknown chromosome number. We present an assembly of the A. deanei nuclear genome based on Oxford Nanopore sequence that resolves into 29 complete or close-to-complete chromosomes. The assembly has several previously unknown special features; it has a supernumerary chromosome, a chromosome with a 340-kb inversion, and there is a translocation between two chromosomes. We also present an updated annotation of the chromosomal genome with 10,365 protein-coding genes, 59 transfer RNAs, 26 ribosomal RNAs, and 62 noncoding RNAs.


2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Jean-Marc Aury ◽  
Benjamin Istace

Abstract Single-molecule sequencing technologies have recently been commercialized by Pacific Biosciences and Oxford Nanopore with the promise of sequencing long DNA fragments (kilobases to megabases order) and then, using efficient algorithms, provide high quality assemblies in terms of contiguity and completeness of repetitive regions. However, the error rate of long-read technologies is higher than that of short-read technologies. This has a direct consequence on the base quality of genome assemblies, particularly in coding regions where sequencing errors can disrupt the coding frame of genes. In the case of diploid genomes, the consensus of a given gene can be a mixture between the two haplotypes and can lead to premature stop codons. Several methods have been developed to polish genome assemblies using short reads and generally, they inspect the nucleotide one by one, and provide a correction for each nucleotide of the input assembly. As a result, these algorithms are not able to properly process diploid genomes and they typically switch from one haplotype to another. Herein we proposed Hapo-G (Haplotype-Aware Polishing Of Genomes), a new algorithm capable of incorporating phasing information from high-quality reads (short or long-reads) to polish genome assemblies and in particular assemblies of diploid and heterozygous genomes.


Author(s):  
Martin Stervander ◽  
William A Cresko

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.


Author(s):  
Nadège Guiglielmoni ◽  
Ramón Rivera-Vicéns ◽  
Romain Koszul ◽  
Jean-François Flot

Non-vertebrate species represent about ~95% of known metazoan (animal) diversity. They remain to this day relatively unexplored genetically, but understanding their genome structure and function is pivotal for expanding our current knowledge of evolution, ecology and biodiversity. Following the continuous improvements and decreasing costs of sequencing technologies, many genome assembly tools have been released, leading to a significant amount of genome projects being completed in recent years. In this review, we examine the current state of genome projects of non-vertebrate animal species. We present an overview of available sequencing technologies, assembly approaches, as well as pre and post-processing steps, genome assembly evaluation methods, and their application to non-vertebrate animal genomes.


Author(s):  
Yasunori Sasakura ◽  
Nicolas Sierro ◽  
Kenta Nakai ◽  
Kazuo Inaba ◽  
Takehiro G. Kusakabe

Plants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 270 ◽  
Author(s):  
Yun Gyeong Lee ◽  
Sang Chul Choi ◽  
Yuna Kang ◽  
Kyeong Min Kim ◽  
Chon-Sik Kang ◽  
...  

The whole genome sequencing (WGS) has become a crucial tool in understanding genome structure and genetic variation. The MinION sequencing of Oxford Nanopore Technologies (ONT) is an excellent approach for performing WGS and it has advantages in comparison with other Next-Generation Sequencing (NGS): It is relatively inexpensive, portable, has simple library preparation, can be monitored in real-time, and has no theoretical limits on reading length. Sorghum bicolor (L.) Moench is diploid (2n = 2x = 20) with a genome size of about 730 Mb, and its genome sequence information is released in the Phytozome database. Therefore, sorghum can be used as a good reference. However, plant species have complex and large genomes when compared to animals or microorganisms. As a result, complete genome sequencing is difficult for plant species. MinION sequencing that produces long-reads can be an excellent tool for overcoming the weak assembly of short-reads generated from NGS by minimizing the generation of gaps or covering the repetitive sequence that appears on the plant genome. Here, we conducted the genome sequencing for S. bicolor cv. BTx623 while using the MinION platform and obtained 895,678 reads and 17.9 gigabytes (Gb) (ca. 25× coverage of reference) from long-read sequence data. A total of 6124 contigs (covering 45.9%) were generated from Canu, and a total of 2661 contigs (covering 50%) were generated from Minimap and Miniasm with a Racon through a de novo assembly using two different tools and mapped assembled contigs against the sorghum reference genome. Our results provide an optimal series of long-read sequencing analysis for plant species while using the MinION platform and a clue to determine the total sequencing scale for optimal coverage that is based on various genome sizes.


Microbiology ◽  
2009 ◽  
Vol 155 (4) ◽  
pp. 1103-1110 ◽  
Author(s):  
Gundula Bosch ◽  
Tiansong Wang ◽  
Ekaterina Latypova ◽  
Marina G. Kalyuzhnaya ◽  
Murray Hackett ◽  
...  

While the shotgun proteomics approach is gaining momentum in understanding microbial physiology, it remains limited by the paucity of high-quality genomic data, especially when it comes to poorly characterized newly identified phyla. At the same time, large-scale metagenomic sequencing projects produce datasets representing genomes of a variety of environmental microbes, although with lower sequence coverage and sequence quality. In this work we tested the utility of a metagenomic dataset enriched in sequences of environmental strains of Methylotenera mobilis, to assess the protein profile of a laboratory-cultivated strain, M. mobilis JLW8, as a proof of principle. We demonstrate that a large portion of the proteome predicted from the metagenomic sequence (approx. 20 %) could be identified with high confidence (three or more peptide sequences), thus gaining insights into the physiology of this bacterium, which represents a new genus within the family Methylophilaceae.


2003 ◽  
Vol 12 (2) ◽  
pp. 196-200 ◽  
Author(s):  
INSOO HYUN

Over the past decade or so, the predominant patient-centered ethos in American bioethics has come under attack by critics who claim that it is morally deficient in certain respects, particularly when viewed in the context of acute-care decisionmaking. One line of criticism has been that the current ethic of patient autonomy gives an individual competent patient far too much decisional authority over the terms of his own treatment so that the patient is at complete liberty to neglect the ways in which his medical decisions can drastically and negatively affect the lives of other family members. Given that family members must help shoulder the financial, emotional, and rehabilitative burdens involved in the patient's care, it has been argued that they too have a legitimate interest in choosing what sort of medical treatment the patient eventually receives. Another closely related line of criticism is that the prevailing focus on patient autonomy gives short shrift to the moral significance of the family as a genuine community. Echoing a view of the person advanced by most communitarian political theorists, some commentators have argued that the patient comes to the clinic so thoroughly embedded in a complex web of familial relationships and obligations that it does not make sense to identify him as the only person in the family to make decisions about treatment.


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