scholarly journals A chromosome-scale genome assembly and karyotype of the ctenophore Hormiphora californensis

Author(s):  
Darrin T Schultz ◽  
Warren R Francis ◽  
Jakob D McBroome ◽  
Lynne M Christianson ◽  
Steven H D Haddock ◽  
...  

Abstract Here, we present a karyotype, a chromosome-scale genome assembly, and a genome annotation from the ctenophore Hormiphora californensis (Ctenophora: Cydippida: Pleurobrachiidae). The assembly spans 110 Mb in 44 scaffolds and 99.47% of the bases are contained in 13 scaffolds. Chromosome micrographs and Hi-C heatmaps support a karyotype of 13 diploid chromosomes. Hi-C data reveal three large heterozygous inversions on chromosome 1, and one heterozygous inversion shares the same gene order found in the genome of the ctenophore Pleurobrachia bachei. We find evidence that H. californensis and P. bachei share thirteen homologous chromosomes, and the same karyotype of 1n = 13. The manually curated PacBio Iso-Seq-based genome annotation reveals complex gene structures, including nested genes and trans-spliced leader sequences. This chromosome-scale assembly is a useful resource for ctenophore biology and will aid future studies of metazoan evolution and phylogenetics.

Author(s):  
Xuankun Li ◽  
Emily Ellis ◽  
David Plotkin ◽  
Yume Imada ◽  
Masaya Yago ◽  
...  

Abstract We provide a new, annotated genome assembly of Neomicropteryx cornuta, a species of the so-called “mandibulate archaic moths” (Lepidoptera: Micropterigidae). These moths belong to a lineage that is thought to have split from all other Lepidoptera more than 300 million years ago and are consequently vital to understanding the early evolution of superorder Amphiesmenoptera, which contains the order Lepidoptera (butterflies and moths) and its sister order Trichoptera (caddisflies). Using PacBio HiFi sequencing reads, we assembled a highly-contiguous genome with a contig N50 of nearly 17 Mbp. The assembled genome length of 541,115,538 bp is about half the length of the largest published Amphiesmenoptera genome (Limnephilus lunatus, Trichoptera) and double the length of the smallest (Papilio polytes, Lepidoptera). We find high recovery of universal single copy orthologs with 98.1% of BUSCO genes present and provide a genome annotation of 15,643 genes aided by resolved isoforms from PacBio IsoSeq data. This high-quality genome assembly provides an important resource for studying ecological and evolutionary transitions in the early evolution of Amphiesmenoptera.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Guifang Lin ◽  
Cheng He ◽  
Jun Zheng ◽  
Dal-Hoe Koo ◽  
Ha Le ◽  
...  

Abstract Background The maize inbred line A188 is an attractive model for elucidation of gene function and improvement due to its high embryogenic capacity and many contrasting traits to the first maize reference genome, B73, and other elite lines. The lack of a genome assembly of A188 limits its use as a model for functional studies. Results Here, we present a chromosome-level genome assembly of A188 using long reads and optical maps. Comparison of A188 with B73 using both whole-genome alignments and read depths from sequencing reads identify approximately 1.1 Gb of syntenic sequences as well as extensive structural variation, including a 1.8-Mb duplication containing the Gametophyte factor1 locus for unilateral cross-incompatibility, and six inversions of 0.7 Mb or greater. Increased copy number of carotenoid cleavage dioxygenase 1 (ccd1) in A188 is associated with elevated expression during seed development. High ccd1 expression in seeds together with low expression of yellow endosperm 1 (y1) reduces carotenoid accumulation, accounting for the white seed phenotype of A188. Furthermore, transcriptome and epigenome analyses reveal enhanced expression of defense pathways and altered DNA methylation patterns of the embryonic callus. Conclusions The A188 genome assembly provides a high-resolution sequence for a complex genome species and a foundational resource for analyses of genome variation and gene function in maize. The genome, in comparison to B73, contains extensive intra-species structural variations and other genetic differences. Expression and network analyses identify discrete profiles for embryonic callus and other tissues.


Author(s):  
Xiaolin Zhao ◽  
Zhichao Zhang ◽  
Sujiao Zheng ◽  
Wenwu Ye ◽  
Xiaobo Zheng ◽  
...  

Diaporthe-Phomopsis disease complex causes considerable yield losses in soybean production worldwide. As one of the major pathogens, Phomopsis longicolla T. W. Hobbs (syn. Diaporthe longicolla) is not only the primary agent of Phomopsis seed decay, but also one of the agents of Phomopsis pod and stem blight, and Phomopsis stem canker. We performed both PacBio long read sequencing and Illumina short read sequencing, and obtained a genome assembly for the P. longicolla strain YC2-1, which was isolated from soybean stem with Phomopsis stem blight disease. The 63.1 Mb genome assembly contains 87 scaffolds, with a minimum, maximum, and N50 scaffold length of 20 kb, 4.6 Mb, and 1.5 Mb respectively, and a total of 17,407 protein-coding genes. The high-quality data expand the genomic resource of P. longicolla species and will provide a solid foundation for a better understanding of their genetic diversity and pathogenic mechanisms.


2020 ◽  
Author(s):  
Catherine Stein ◽  
Penelope Bencheck ◽  
Jacquelaine Bartlett ◽  
Robert P Igo ◽  
Rafal S Sobota ◽  
...  

Background: Tuberculosis (TB) is the most deadly infectious disease globally and highly prevalent in the developing world, especially sub-Saharan Africa. Even though a third of humans are exposed to Myocbacterium tuberculosis (Mtb), most infected immunocompetent individuals do not develop active TB. In contrast, for individuals infected with both TB and the human immunodeficiency virus (HIV), the risk of active disease is 10% or more per year. Previously, we identified in a genome-wide association study a region on chromosome 5 that was associated with resistance to TB. This region included epigenetic marks that could influence gene regulation so we hypothesized that HIV-infected individuals exposed to Mtb, who remain disease free, carry epigenetic changes that strongly protect them from active TB. To test this hypothesis, we conducted a methylome-wide study in HIV-infected, TB-exposed cohorts from Uganda and Tanzania. Results: In 221 HIV-infected adults from Uganda and Tanzania, we identified 3 regions of interest that included markers that were differentially methylated between TB cases and LTBI controls, that also included methylation QTLs and associated SNPs: chromosome 1 (RNF220, p=4x10-5), chromosome 2 (between COPS8 and COL6A3 genes, p=2.7x10-5), and chromosome 5 (CEP72, p=1.3x10-5). These methylation results colocalized with associated SNPs, methylation QTLs, and methylation x SNP interaction effects. These markers were in regions with regulatory markers for cells involved in TB immunity and/or lung. Conclusion: Epigenetic regulation is a potential biologic factor underlying resistance to TB in immunocompromised individuals that can act in conjunction with genetic variants.


2021 ◽  
Vol 6 ◽  
pp. 258
Author(s):  
Konrad Lohse ◽  
Alexander Mackintosh ◽  
Roger Vila ◽  
◽  
◽  
...  

We present a genome assembly from an individual male Aglais io (also known as Inachis io and Nymphalis io) (the European peacock; Arthropoda; Insecta; Lepidoptera; Nymphalidae). The genome sequence is 384 megabases in span. The majority (99.91%) of the assembly is scaffolded into 31 chromosomal pseudomolecules, with the Z sex chromosome assembled. Gene annotation of this assembly on Ensembl has identified 11,420 protein coding genes.


2021 ◽  
Vol 6 ◽  
pp. 322
Author(s):  
Liam Crowley ◽  
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◽  
◽  
◽  
...  

We present a genome assembly from an individual female Malachius bipustulatus (the common malachite beetle; Arthropoda; Insecta; Coleoptera; Melyridae). The genome sequence is 544 megabases in span. The majority (99.70%) of the assembly is scaffolded into 10 chromosomal pseudomolecules, with the X sex chromosome assembled.


2021 ◽  
Vol 6 ◽  
pp. 112
Author(s):  
Dan Mead ◽  
Rob Ogden ◽  
Anna Meredith ◽  
Gabriela Peniche ◽  
Michelle Smith ◽  
...  

We present a genome assembly from an individual female Aquila chrysaetos chrysaetos (the European golden eagle; Chordata; Aves; Accipitridae). The genome sequence is 1.23 gigabases in span. The majority of the assembly is scaffolded into 28 chromosomal pseudomolecules, including the W and Z sex chromosomes.


2020 ◽  
Vol 5 ◽  
pp. 27
Author(s):  
Dan Mead ◽  
Kathryn Fingland ◽  
Rachel Cripps ◽  
Roberto Portela Miguez ◽  
Michelle Smith ◽  
...  

We present a genome assembly from an individual male Sciurus carolinensis (the eastern grey squirrel; Vertebrata; Mammalia; Eutheria; Rodentia; Sciuridae). The genome sequence is 2.82 gigabases in span. The majority of the assembly (92.3%) is scaffolded into 21 chromosomal-level scaffolds, with both X and Y sex chromosomes assembled.


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.


2019 ◽  
Author(s):  
Shan Gao

AbstractHeterosis has been widely exploited in animal and plant breeding to enhance the productive traits of hybrid progeny of two breeds or two species. Although, there were multiple models for explaining the hybrid vigor, such as dominance and over-dominance hypothesis, its underlying molecular genetic mechanisms remain equivocal. The aim of this study is through comparing the different expression genes (DEGs) and different alternative splicing (DAS) genes to explore the mechanism of heterosis. Here, we performed a genome-wide gene expression and alternative splicing analysis of two heterotic crosses between donkey and horse in three tissues. The results showed that the DAS genes influenced the heterosis-related phenotypes in a unique than DEGs and about 10% DEGs are DAS genes. In addition, over 69.7% DEGs and 87.2% DAS genes showed over-dominance or dominance, respectively. Furthermore, the “Muscle Contraction” and “Neuronal System” pathways were significantly enriched both for the DEGs and DAS genes in muscle. TNNC2 and RYR1 genes may contribute to mule’s great endurance while GRIA2 and GRIN1 genes may be related with mule’s cognition. Together, these DEGs and DAS genes provide the candidates for future studies of the genetic and molecular mechanism of heterosis in mule.


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