Advanced cytogenetic physical mapping for the development of chromosome-based genome assemblies

2016 ◽  
Author(s):  
Maria V. Sharakhova
Keyword(s):  
Physical Mapping ◽  
Genome Assemblies

scholarly journals Physical Mapping of the Anopheles (Nyssorhynchus) darlingi Genomic Scaffolds

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 164
Author(s):  
Míriam Silva Rafael ◽  
Leticia Cegatti Bridi ◽  
Igor V. Sharakhov ◽  
Osvaldo Marinotti ◽  
Maria V. Sharakhova ◽  
...  
Keyword(s):  
Physical Mapping ◽  
Genomic Dna ◽  
Chromosomal Rearrangements ◽  
Polytene Chromosomes ◽  
Anopheles Darlingi ◽  
Anopheles Albimanus ◽  
Anopheles Species ◽  
Homologous Sequences ◽  
Genome Assemblies

The genome assembly of Anopheles darlingi consists of 2221 scaffolds (N50 = 115,072 bp) and has a size spanning 136.94 Mbp. This assembly represents one of the smallest genomes among Anopheles species. Anopheles darlingi genomic DNA fragments of ~37 Kb were cloned, end-sequenced, and used as probes for fluorescence in situ hybridization (FISH) with salivary gland polytene chromosomes. In total, we mapped nine DNA probes to scaffolds and autosomal arms. Comparative analysis of the An. darlingi scaffolds with homologous sequences of the Anopheles albimanus and Anopheles gambiae genomes identified chromosomal rearrangements among these species. Our results confirmed that physical mapping is a useful tool for anchoring genome assemblies to mosquito chromosomes.

scholarly journals Four chromosome scale genomes and a pan-genome annotation to accelerate pecan tree breeding

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
John T. Lovell ◽  
Nolan B. Bentley ◽  
Gaurab Bhattarai ◽  
Jerry W. Jenkins ◽  
Avinash Sreedasyam ◽  
...  
Keyword(s):  
Tree Breeding ◽  
Pathogen Resistance ◽  
Perennial Crop ◽  
Crop Species ◽  
Annotation Database ◽  
Pan Genome ◽  
Genome Integration ◽  
Transformative Potential ◽  
Genome Assemblies ◽  
Quantitative Genomics

AbstractGenome-enabled biotechnologies have the potential to accelerate breeding efforts in long-lived perennial crop species. Despite the transformative potential of molecular tools in pecan and other outcrossing tree species, highly heterozygous genomes, significant presence–absence gene content variation, and histories of interspecific hybridization have constrained breeding efforts. To overcome these challenges, here, we present diploid genome assemblies and annotations of four outbred pecan genotypes, including a PacBio HiFi chromosome-scale assembly of both haplotypes of the ‘Pawnee’ cultivar. Comparative analysis and pan-genome integration reveal substantial and likely adaptive interspecific genomic introgressions, including an over-retained haplotype introgressed from bitternut hickory into pecan breeding pedigrees. Further, by leveraging our pan-genome presence–absence and functional annotation database among genomes and within the two outbred haplotypes of the ‘Lakota’ genome, we identify candidate genes for pest and pathogen resistance. Combined, these analyses and resources highlight significant progress towards functional and quantitative genomics in highly diverse and outbred crops.

scholarly journals Chromosomal assembly of the nuclear genome of the endosymbiont-bearing trypanosomatid Angomonas deanei

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
John W Davey ◽  
Carolina M C Catta-Preta ◽  
Sally James ◽  
Sarah Forrester ◽  
Maria Cristina M Motta ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Noncoding Rnas ◽  
Nuclear Genome ◽  
Supernumerary Chromosome ◽  
Ribosomal Rnas ◽  
Protein Coding ◽  
Transfer Rnas ◽  
Protein Coding Genes ◽  
Oxford Nanopore ◽  
Genome Assemblies

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.

scholarly journals The Distribution of Several Genomic Virulence Determinants Does Not Corroborate the Established Serotyping Classification of Bacillus thuringiensis

2021 ◽  
Vol 22 (5) ◽  
pp. 2244
Author(s):  
Anton E. Shikov ◽  
Yury V. Malovichko ◽  
Arseniy A. Lobov ◽  
Maria E. Belousova ◽  
Anton A. Nizhnikov ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Protein Identification ◽  
Core Gene ◽  
Comparative Genomic ◽  
Virulence Determinants ◽  
Strain Characterization ◽  
Proteomic Approach ◽  
Liquid Chromatography Tandem Mass ◽  
Identity Threshold ◽  
Genome Assemblies

Bacillus thuringiensis, commonly referred to as Bt, is an object of the lasting interest of microbiologists due to its highly effective insecticidal properties, which make Bt a prominent source of biologicals. To categorize the exuberance of Bt strains discovered, serotyping assays are utilized in which flagellin serves as a primary seroreactive molecule. Despite its convenience, this approach is not indicative of Bt strains’ phenotypes, neither it reflects actual phylogenetic relationships within the species. In this respect, comparative genomic and proteomic techniques appear more informative, but their use in Bt strain classification remains limited. In the present work, we used a bottom-up proteomic approach based on fluorescent two-dimensional difference gel electrophoresis (2D-DIGE) coupled with liquid chromatography/tandem mass spectrometry(LC-MS/MS) protein identification to assess which stage of Bt culture, vegetative or spore, would be more informative for strain characterization. To this end, the proteomic differences for the israelensis-attributed strains were assessed to compare sporulating cultures of the virulent derivative to the avirulent one as well as to the vegetative stage virulent bacteria. Using the same approach, virulent spores of the israelensis strain were also compared to the spores of strains belonging to two other major Bt serovars, namely darmstadiensis and thuringiensis. The identified proteins were analyzed regarding the presence of the respective genes in the 104 Bt genome assemblies available at open access with serovar attributions specified. Of 21 proteins identified, 15 were found to be encoded in all the present assemblies at 67% identity threshold, including several virulence factors. Notable, individual phylogenies of these core genes conferred neither the serotyping nor the flagellin-based phylogeny but corroborated the reconstruction based on phylogenomics approaches in terms of tree topology similarity. In its turn, the distribution of accessory protein genes was not confined to the existing serovars. The obtained results indicate that neither gene presence nor the core gene sequence may serve as distinctive bases for the serovar attribution, undermining the notion that the serotyping system reflects strains’ phenotypic or genetic similarity. We also provide a set of loci, which fit in with the phylogenomics data plausibly and thus may serve for draft phylogeny estimation of the novel strains.

scholarly journals Genome Assembly of the Canadian Two-row Malting Barley Cultivar AAC Synergy

2021 ◽  
Author(s):  
Wayne Xu ◽  
James R Tucker ◽  
Wubishet A Bekele ◽  
Frank M You ◽  
Yong-Bi Fu ◽  
...  
Keyword(s):  
Reference Genome ◽  
Single Copy ◽  
Barley Cultivar ◽  
Malting Barley ◽  
Orthologous Genes ◽  
Hordeum Vulgare L ◽  
Chromosome Conformation ◽  
Mate Pair ◽  
Genome Assemblies ◽  
First Time

Abstract Barley (Hordeum vulgare L.) is one of the most important global crops. The six-row barley cultivar Morex reference genome has been used by the barley research community worldwide. However, this reference genome can have limitations when used for genomic and genetic diversity analysis studies, gene discovery, and marker development when working in two-row germplasm that is more common to Canadian barley. Here we assembled, for the first time, the genome sequence of a Canadian two-row malting barley, cultivar AAC Synergy. We applied deep Illumina paired-end reads, long mate-pair reads, PacBio sequences, 10X chromium linked read libraries, and chromosome conformation capture sequencing (Hi-C) to generate a contiguous assembly. The genome assembled from super-scaffolds had a size of 4.85 Gb, N50 of 2.32 Mb and an estimated 93.9% of complete genes from a plant database (BUSCO, benchmarking universal single-copy orthologous genes). After removal of small scaffolds (< 300 Kb), the assembly was arranged into pseudomolecules of 4.14 Gb in size with seven chromosomes plus unanchored scaffolds. The completeness and annotation of the assembly were assessed by comparing it with the updated version of six-row Morex and recently released two-row Golden Promise genome assemblies.

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