scholarly journals Chromosome-level reference genome of the European wasp spider Argiope bruennichi: a resource for studies on range expansion and evolutionary adaptation

GigaScience ◽  
2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Monica M Sheffer ◽  
Anica Hoppe ◽  
Henrik Krehenwinkel ◽  
Gabriele Uhl ◽  
Andreas W Kuss ◽  
...  

Abstract Background Argiope bruennichi, the European wasp spider, has been investigated intensively as a focal species for studies on sexual selection, chemical communication, and the dynamics of rapid range expansion at a behavioral and genetic level. However, the lack of a reference genome has limited insights into the genetic basis for these phenomena. Therefore, we assembled a high-quality chromosome-level reference genome of the European wasp spider as a tool for more in-depth future studies. Findings We generated, de novo, a 1.67 Gb genome assembly of A. bruennichi using 21.8× Pacific Biosciences sequencing, polished with 19.8× Illumina paired-end sequencing data, and proximity ligation (Hi-C)-based scaffolding. This resulted in an N50 scaffold size of 124 Mb and an N50 contig size of 288 kb. We found 98.4% of the genome to be contained in 13 scaffolds, fitting the expected number of chromosomes (n = 13). Analyses showed the presence of 91.1% of complete arthropod BUSCOs, indicating a high-quality assembly. Conclusions We present the first chromosome-level genome assembly in the order Araneae. With this genomic resource, we open the door for more precise and informative studies on evolution and adaptation not only in A. bruennichi but also in arachnids overall, shedding light on questions such as the genomic architecture of traits, whole-genome duplication, and the genomic mechanisms behind silk and venom evolution.

Author(s):  
Monica M. Sheffer ◽  
Anica Hoppe ◽  
Henrik Krehenwinkel ◽  
Gabriele Uhl ◽  
Andreas W. Kuss ◽  
...  

AbstractBackgroundArgiope bruennichi, the European wasp spider, has been studied intensively as to sexual selection, chemical communication, and the dynamics of rapid range expansion at a behavioral and genetic level. However, the lack of a reference genome has limited insights into the genetic basis for these phenomena. Therefore, we assembled a high-quality chromosome-level reference genome of the European wasp spider as a tool for more in-depth future studies.FindingsWe generated, de novo, a 1.67Gb genome assembly of A. bruennichi using 21.5X PacBio sequencing, polished with 30X Illumina paired-end sequencing data, and proximity ligation (Hi-C) based scaffolding. This resulted in an N50 scaffold size of 124Mb and an N50 contig size of 288kb. We found 98.4% of the genome to be contained in 13 scaffolds, fitting the expected number of chromosomes (n = 13). Analyses showed the presence of 91.1% of complete arthropod BUSCOs, indicating a high quality of the assembly.ConclusionsWe present the first chromosome-level genome assembly in the class Arachnida. With this genomic resource, we open the door for more precise and informative studies on evolution and adaptation in A. bruennichi, as well as on several interesting topics in Arachnids, such as the genomic architecture of traits, whole genome duplication and the genomic mechanisms behind silk and venom evolution.


2021 ◽  
Author(s):  
Xinxin Yi ◽  
Jing Liu ◽  
Shengcai Chen ◽  
Hao Wu ◽  
Min Liu ◽  
...  

Cultivated soybean (Glycine max) is an important source for protein and oil. Many elite cultivars with different traits have been developed for different conditions. Each soybean strain has its own genetic diversity, and the availability of more high-quality soybean genomes can enhance comparative genomic analysis for identifying genetic underpinnings for its unique traits. In this study, we constructed a high-quality de novo assembly of an elite soybean cultivar Jidou 17 (JD17) with chromsome contiguity and high accuracy. We annotated 52,840 gene models and reconstructed 74,054 high-quality full-length transcripts. We performed a genome-wide comparative analysis based on the reference genome of JD17 with three published soybeans (WM82, ZH13 and W05) , which identified five large inversions and two large translocations specific to JD17, 20,984 - 46,912 PAVs spanning 13.1 - 46.9 Mb in size, and 5 - 53 large PAV clusters larger than 500kb. 1,695,741 - 3,664,629 SNPs and 446,689 - 800,489 Indels were identified and annotated between JD17 and them. Symbiotic nitrogen fixation (SNF) genes were identified and the effects from these variants were further evaluated. It was found that the coding sequences of 9 nitrogen fixation-related genes were greatly affected. The high-quality genome assembly of JD17 can serve as a valuable reference for soybean functional genomics research.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9114 ◽  
Author(s):  
Jiawei Wang ◽  
Weizhen Liu ◽  
Dongzi Zhu ◽  
Xiang Zhou ◽  
Po Hong ◽  
...  

The sweet cherry (Prunus avium) is one of the most economically important fruit species in the world. However, there is a limited amount of genetic information available for this species, which hinders breeding efforts at a molecular level. We were able to describe a high-quality reference genome assembly and annotation of the diploid sweet cherry (2n = 2x = 16) cv. Tieton using linked-read sequencing technology. We generated over 750 million clean reads, representing 112.63 GB of raw sequencing data. The Supernova assembler produced a more highly-ordered and continuous genome sequence than the current P. avium draft genome, with a contig N50 of 63.65 KB and a scaffold N50 of 2.48 MB. The final scaffold assembly was 280.33 MB in length, representing 82.12% of the estimated Tieton genome. Eight chromosome-scale pseudomolecules were constructed, completing a 214 MB sequence of the final scaffold assembly. De novo, homology-based, and RNA-seq methods were used together to predict 30,975 protein-coding loci. 98.39% of core eukaryotic genes and 97.43% of single copy orthologues were identified in the embryo plant, indicating the completeness of the assembly. Linked-read sequencing technology was effective in constructing a high-quality reference genome of the sweet cherry, which will benefit the molecular breeding and cultivar identification in this species.


GigaScience ◽  
2019 ◽  
Vol 8 (11) ◽  
Author(s):  
Sihan Lu ◽  
Jie Yang ◽  
Xuelei Dai ◽  
Feiang Xie ◽  
Jinwu He ◽  
...  

AbstractBackgroundPapilio bianor Cramer, 1777 (commonly known as the Chinese peacock butterfly) (Insecta, Lepidoptera, Papilionidae) is a widely distributed swallowtail butterfly with a wide number of geographic populations ranging from the southeast of Russia to China, Japan, India, Vietnam, Myanmar, and Thailand. Its wing color consists of both pigmentary colored scales (black, reddish) and structural colored scales (iridescent blue or green dust). A high-quality reference genome of P. bianor is an important foundation for investigating iridescent color evolution, phylogeography, and the evolution of swallowtail butterflies.FindingsWe obtained a chromosome-level de novo genome assembly of the highly heterozygous P. bianor using long Pacific Biosciences sequencing reads and high-throughput chromosome conformation capture technology. The final assembly is 421.52 Mb on 30 chromosomes (29 autosomes and 1 Z sex chromosome) with 13.12 Mb scaffold N50. In total, 15,375 protein-coding genes and 233.09 Mb of repetitive sequences were identified. Phylogenetic analyses indicated that P. bianor separated from a common ancestor of swallowtails ∼23.69–36.04 million years ago. Demographic history suggested that the population expansion of this species from the last interglacial period to the last glacial maximum possibly resulted from its decreased natural enemies and its adaptation to climate change during the glacial period.ConclusionsWe present a high-quality chromosome-level reference genome of P. bianor using long-read single-molecule sequencing and Hi-C–based chromatin interaction maps. Our results lay the foundation for exploring the genetic basis of special biological features of P. bianor and also provide a useful data source for comparative genomics and phylogenomics among butterflies and moths.


2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Linlin Zhao ◽  
Shengyong Xu ◽  
Zhiqiang Han ◽  
Qi Liu ◽  
Wensi Ke ◽  
...  

Abstract Argyrosomus japonicus is an economically and ecologically important fish species in the family Sciaenidae with a wide distribution in the world’s oceans. Here, we report a high-quality, chromosome-level genome assembly of A. japonicus based on PacBio and Hi-C sequencing technology. A 673.7-Mb genome containing 282 contigs with an N50 length of 18.4 Mb was obtained based on PacBio long reads. These contigs were further ordered and clustered into 24 chromosome groups based on Hi-C data. In addition, a total of 217.2 Mb (32.24% of the assembled genome) of sequences were identified as repeat elements, and 23,730 protein-coding genes were predicted based on multiple approaches. More than 97% of BUSCO genes were identified in the A. japonicus genome. The high-quality genome assembled in this work not only provides a valuable genomic resource for future population genetics, conservation biology and selective breeding studies of A. japonicus but also lays a solid foundation for the study of Sciaenidae evolution.


2019 ◽  
Author(s):  
Yinghui Dong ◽  
Qifan Zeng ◽  
Jianfeng Ren ◽  
Hanhan Yao ◽  
Wenbin Ruan ◽  
...  

AbstractBackgroundThe Chinese razor clam, Sinonovacula constricta, is one of the commercially important marine bivalves with deep-burrowing lifestyle and remarkable adaptability of broad-range salinity. Despite its economic impact and representative of the less-understood deep-burrowing bivalve lifestyle, there are few genomic resources for exploring its unique biology and adaptive evolution. Herein, we reported a high-quality chromosomal-level reference genome of S. constricta, the first genome of the family Solenidae, along with a large amount of short-read/full-length transcriptomic data of whole-ontogeny developmental stages, all major adult tissues, and gill tissues under salinity challenge.FindingsA total of 101.79 Gb and 129.73 Gb sequencing data were obtained with the PacBio and Illumina platforms, which represented approximately 186.63X genome coverage. In addition, a total of 160.90 Gb and 24.55 Gb clean data were also obtained with the Illumina and PacBio platforms for transcriptomic investigation. A de novo genome assembly of 1,340.13 Mb was generated, with a contig N50 of 689.18 kb. Hi-C scaffolding resulted in 19 chromosomes with a scaffold N50 of 57.99 Mb. The repeat sequences account for 50.71% of the assembled genome. A total of 26,273 protein-coding genes were predicted and 99.5% of them were annotated. Phylogenetic analysis revealed that S. constricta diverged from the lineage of Pteriomorphia at approximately 494 million years ago. Notably, cytoskeletal protein tubulin and motor protein dynein gene families are rapidly expanded in the S. constricta genome and are highly expressed in the mantle and gill, implicating potential genomic bases for the well-developed ciliary system in the S. constricta.ConclusionsThe high-quality genome assembly and comprehensive transcriptomes generated in this work not only provides highly valuable genomic resources for future studies of S. constricta, but also lays a solid foundation for further investigation into the adaptive mechanisms of benthic burrowing mollusks.


2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 23-24
Author(s):  
Kimberly M Davenport ◽  
Derek M Bickhart ◽  
Kim Worley ◽  
Shwetha C Murali ◽  
Noelle Cockett ◽  
...  

Abstract Sheep are an important agricultural species used for both food and fiber in the United States and globally. A high-quality reference genome enhances the ability to discover genetic and biological mechanisms influencing important traits, such as meat and wool quality. The rapid advances in genome assembly algorithms and emergence of increasingly long sequence read length provide the opportunity for an improved de novo assembly of the sheep reference genome. Tissue was collected postmortem from an adult Rambouillet ewe selected by USDA-ARS for the Ovine Functional Annotation of Animal Genomes project. Short-read (55x coverage), long-read PacBio (75x coverage), and Hi-C data from this ewe were retrieved from public databases. We generated an additional 50x coverage of Oxford Nanopore data and assembled the combined long-read data with canu v1.9. The assembled contigs were polished with Nanopolish v0.12.5 and scaffolded using Hi-C data with Salsa v2.2. Gaps were filled with PBsuite v15.8.24 and polished with Nanopolish v0.12.5 followed by removal of duplicate contigs with PurgeDups v1.0.1. Chromosomes were oriented by identifying centromeres and telomeres with RepeatMasker v4.1.1, indicating a need to reverse the orientation of chromosome 11 relative to Oar_rambouillet_v1.0. Final polishing was performed with two rounds of a pipeline which consisted of freebayes v1.3.1 to call variants, Merfin to validate them, and BCFtools to generate the consensus fasta. The ARS-UI_Ramb_v2.0 assembly has improved continuity (contig N50 of 43.19 Mb) with a 19-fold and 38-fold decrease in the number of scaffolds compared with Oar_rambouillet_v1.0 and Oar_v4.0. ARS-UI_Ramb_v2.0 has greater per-base accuracy and fewer insertions and deletions identified from mapped RNA sequence than previous assemblies. This significantly improved reference assembly, public at NCBI GenBank under accession number GCA_016772045, will optimize the functional annotation of the sheep genome and facilitate improved mapping accuracy of genetic variant and expression data for traits relevant the sheep industry.


GigaScience ◽  
2020 ◽  
Vol 9 (2) ◽  
Author(s):  
De-Lu Ning ◽  
Tao Wu ◽  
Liang-Jun Xiao ◽  
Ting Ma ◽  
Wen-Liang Fang ◽  
...  

Abstract Background Juglans sigillata, or iron walnut, belonging to the order Juglandales, is an economically important tree species in Asia, especially in the Yunnan province of China. However, little research has been conducted on J. sigillata at the molecular level, which hinders understanding of its evolution, speciation, and synthesis of secondary metabolites, as well as its wide adaptability to its plateau environment. To address these issues, a high-quality reference genome of J. sigillata would be useful. Findings To construct a high-quality reference genome for J. sigillata, we first generated 38.0 Gb short reads and 66.31 Gb long reads using Illumina and Nanopore sequencing platforms, respectively. The sequencing data were assembled into a 536.50-Mb genome assembly with a contig N50 length of 4.31 Mb. Additionally, we applied BioNano technology to identify contacts among contigs, which were then used to assemble contigs into scaffolds, resulting in a genome assembly with scaffold N50 length of 16.43 Mb and contig N50 length of 4.34 Mb. To obtain a chromosome-level genome assembly, we constructed 1 Hi-C library and sequenced 79.97 Gb raw reads using the Illumina HiSeq platform. We anchored ∼93% of the scaffold sequences into 16 chromosomes and evaluated the quality of our assembly using the high contact frequency heat map. Repetitive elements account for 50.06% of the genome, and 30,387 protein-coding genes were predicted from the genome, of which 99.8% have been functionally annotated. The genome-wide phylogenetic tree indicated an estimated divergence time between J. sigillata and Juglans regia of 49 million years ago on the basis of single-copy orthologous genes. Conclusions We provide the first chromosome-level genome for J. sigillata. It will lay a valuable foundation for future research on the genetic improvement of J. sigillata.


2020 ◽  
Author(s):  
Mohamed Awad ◽  
Xiangchao Gan

AbstractHigh-quality genome assembly has wide applications in genetics and medical studies. However, it is still very challenging to achieve gap-free chromosome-scale assemblies using current workflows for long-read platforms. Here we propose GALA (Gap-free long-read assembler), a chromosome-by-chromosome assembly method implemented through a multi-layer computer graph that identifies mis-assemblies within preliminary assemblies or chimeric raw reads and partitions the data into chromosome-scale linkage groups. The subsequent independent assembly of each linkage group generates a gap-free assembly free from the mis-assembly errors which usually hamper existing workflows. This flexible framework also allows us to integrate data from various technologies, such as Hi-C, genetic maps, a reference genome and even motif analyses, to generate gap-free chromosome-scale assemblies. We de novo assembled the C. elegans and A. thaliana genomes using combined Pacbio and Nanopore sequencing data from publicly available datasets. We also demonstrated the new method’s applicability with a gap-free assembly of a human genome with the help a reference genome. In addition, GALA showed promising performance for Pacbio high-fidelity long reads. Thus, our method enables straightforward assembly of genomes with multiple data sources and overcomes barriers that at present restrict the application of de novo genome assembly technology.


2021 ◽  
Vol 12 ◽  
Author(s):  
Min Tang ◽  
Suqun He ◽  
Xun Gong ◽  
Peng Lü ◽  
Rehab H. Taha ◽  
...  

The reference genomes of Bombyx mori (B. mori), Silkworm Knowledge-based database (SilkDB) and SilkBase, have served as the gold standard for nearly two decades. Their use has fundamentally shaped model organisms and accelerated relevant studies on lepidoptera. However, the current reference genomes of B. mori do not accurately represent the full set of genes for any single strain. As new genome-wide sequencing technologies have emerged and the cost of high-throughput sequencing technology has fallen, it is now possible for standard laboratories to perform full-genome assembly for specific strains. Here we present a high-quality de novo chromosome-level genome assembly of a single B. mori with nuclear polyhedrosis virus (BmNPV) resistance through the integration of PacBio long-read sequencing, Illumina short-read sequencing, and Hi-C sequencing. In addition, regular bioinformatics analyses, such as gene family, phylogenetic, and divergence analyses, were performed. The sample was from our unique B. mori species (NB), which has strong inborn resistance to BmNPV. Our genome assembly showed good collinearity with SilkDB and SilkBase and particular regions. To the best of our knowledge, this is the first genome assembly with BmNPV resistance, which should be a more accurate insect model for resistance studies.


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