scholarly journals Evolution of Complexity. Molecular Aspects of Preassembly

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6618
Author(s):  
Fredric M. Menger ◽  
Syed A. A. Rizvi
Keyword(s):  
Complex Traits ◽  
De Novo ◽  
Genetic Material ◽  
Cambrian Explosion ◽  
Epigenetic Factors ◽  
Evolution Of Complexity ◽  
De Novo Genes ◽  
Species Expansion ◽  
Molecular Aspects ◽  
Costly Traits

An extension of neo-Darwinism, termed preassembly, states that genetic material required for many complex traits, such as echolocation, was present long before emergence of the traits. Assembly of genes and gene segments had occurred over protracted time-periods within large libraries of non-coding genes. Epigenetic factors ultimately promoted transfers from noncoding to coding genes, leading to abrupt formation of the trait via de novo genes. This preassembly model explains many observations that to this present day still puzzle biologists: formation of super-complexity in the absence of multiple fossil precursors, as with bat echolocation and flowering plants; major genetic and physical alterations occurring in just a few thousand years, as with housecat evolution; lack of precursors preceding lush periods of species expansion, as in the Cambrian explosion; and evolution of costly traits that exceed their need during evolutionary times, as with human intelligence. What follows in this paper is a mechanism that is not meant to supplant neo-Darwinism; instead, preassembly aims to supplement current ideas when complexity issues leave them struggling.

scholarly journals Comparative genomics and pangenome-oriented studies reveal high homogeneity of the agronomically relevant enterobacterial plant pathogen Dickeya solani

2020 ◽  
Author(s):  
Agata Motyka-Pomagruk ◽  
Sabina Zoledowska ◽  
Agnieszka Emilia Misztak ◽  
Wojciech Sledz ◽  
Alessio Mengoni ◽  
...  
Keyword(s):  
Comparative Genomics ◽  
Large Scale ◽  
De Novo ◽  
Genetic Material ◽  
Soft Rot ◽  
Potato Production ◽  
Core Gene ◽  
Ecological Niches ◽  
Dickeya Solani ◽  
High Level

Abstract Background: Dickeya solani is an important plant pathogenic bacterium causing severe losses in European potato production. This species draws a lot of attention due to its remarkable virulence, great devastating potential and easier spread in contrast to other Dickeya spp. In view of a high need for extensive studies on economically important soft rot Pectobacteriaceae , we performed a comparative genomics analysis on D. solani strains to search for genetic foundations that would explain the differences in the observed virulence levels within the D. solani population. Results: High quality assemblies of 8 de novo sequenced D. solani genomes have been obtained. Whole-sequence comparison, ANIb, ANIm, Tetra and pangenome-oriented analyses performed on these genomes and the sequences of 14 additional strains revealed an exceptionally high level of homogeneity among the studied genetic material of D. solani strains. With the use of 22 genomes, the pangenome of D. solani , comprising 84.7% core, 7.2% accessory and 8.1% unique genes, has been almost completely determined, suggesting the presence of a nearly closed pangenome structure. Attribution of the genes included in the D. solani pangenome fractions to functional COG categories showed that higher percentages of accessory and unique pangenome parts in contrast to the core section are encountered in phage/mobile elements- and transcription- associated groups with the genome of RNS 05.1.2A strain having the most significant impact. Also, the first D. solani large-scale genome-wide phylogeny computed on concatenated core gene alignments is herein reported. Conclusions: The almost closed status of D. solani pangenome achieved in this work points to the fact that the unique gene pool of this species should no longer expand. Such a feature is characteristic of taxa whose representatives either occupy isolated ecological niches or lack efficient mechanisms for gene exchange and recombination, which seems rational concerning a strictly pathogenic species with clonal population structure. Finally, no obvious correlations between the geographical origin of D. solani strains and their phylogeny were found, which might reflect the specificity of the international seed potato market.

scholarly journals A genome resource for green millet Setaria viridis enables discovery of agronomically valuable loci

2020 ◽  
Vol 38 (10) ◽  
pp. 1203-1210 ◽  
Author(s):  
Sujan Mamidi ◽  
Adam Healey ◽  
Pu Huang ◽  
Jane Grimwood ◽  
Jerry Jenkins ◽  
...  
Keyword(s):  
Complex Traits ◽  
De Novo ◽  
Foxtail Millet ◽  
Wild Plant ◽  
Leaf Angle ◽  
Setaria Viridis ◽  
Model Species ◽  
Seed Shattering ◽  
A Genome ◽  
Wild Accessions

Abstract Wild and weedy relatives of domesticated crops harbor genetic variants that can advance agricultural biotechnology. Here we provide a genome resource for the wild plant green millet (Setaria viridis), a model species for studies of C4 grasses, and use the resource to probe domestication genes in the close crop relative foxtail millet (Setaria italica). We produced a platinum-quality genome assembly of S. viridis and de novo assemblies for 598 wild accessions and exploited these assemblies to identify loci underlying three traits: response to climate, a ‘loss of shattering’ trait that permits mechanical harvest and leaf angle, a predictor of yield in many grass crops. With CRISPR–Cas9 genome editing, we validated Less Shattering1 (SvLes1) as a gene whose product controls seed shattering. In S. italica, this gene was rendered nonfunctional by a retrotransposon insertion in the domesticated loss-of-shattering allele SiLes1-TE (transposable element). This resource will enhance the utility of S. viridis for dissection of complex traits and biotechnological improvement of panicoid crops.

scholarly journals A Continuum of Evolving De Novo Genes Drives Protein-Coding Novelty in Drosophila

2020 ◽  
Vol 88 (4) ◽  
pp. 382-398 ◽  
Author(s):  
Brennen Heames ◽  
Jonathan Schmitz ◽  
Erich Bornberg-Bauer
Keyword(s):  
De Novo ◽  
Protein Coding ◽  
De Novo Genes

Origination and evolution of orphan genes and de novo genes in the genome of Caenorhabditis elegans

2019 ◽  
Vol 62 (4) ◽  
pp. 579-593 ◽  
Author(s):  
Wenyu Zhang ◽  
Yuanxiao Gao ◽  
Manyuan Long ◽  
Bairong Shen
Keyword(s):  
Caenorhabditis Elegans ◽  
De Novo ◽  
Orphan Genes ◽  
De Novo Genes

scholarly journals Changthangi Pashmina Goat Genome: Sequencing, Assembly, and Annotation

2021 ◽  
Vol 12 ◽  
Author(s):  
Basharat Bhat ◽  
Nazir A. Ganai ◽  
Ashutosh Singh ◽  
Rakeeb Mir ◽  
Syed Mudasir Ahmad ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Complex Traits ◽  
Defense Mechanism ◽  
De Novo ◽  
Whole Genome Sequence ◽  
Illumina Hiseq ◽  
Single Nucleotide ◽  
The Public ◽  
Assembly Analysis ◽  
Insight Into

Pashmina goats produce the world's finest and the most costly animal fiber (Pashmina) with an average fineness of 11–13 microns and have more evolved mechanisms than any known goat breed around the globe. Despite the repute of Pashmina goat for producing the finest and most sought-after animal fiber, meager information is available in the public domain about Pashmina genomics and transcriptomics. Here we present a 2.94 GB genome sequence from a male Changthangi white Pashmina goat. We generated 294.8 GB (>100X coverage) of the whole-genome sequence using the Illumina HiSeq 2500 sequencer. All cleaned reads were mapped to the goat reference genome (2,922,813,246 bp) which covers 97.84% of the genome. The Unaligned reads were used for de novo assembly resulting in a total of 882 MB non-reference contigs. De novo assembly analysis presented in this study provides important insight into the adaptation of Pashmina goats to cold stress and helps enhance our understanding of this complex phenomenon. A comparison of the Pashmina goat genome with a wild goat genome revealed a total of 2,823 high impact single nucleotide variations and small insertions and deletions, which may be associated with the evolution of Pashmina goats. The Pashmina goat genome sequence provided in this study may improve our understanding of complex traits found in Pashmina goats, such as annual fiber cycling, defense mechanism against hypoxic, survival secret in extremely cold conditions, and adaptation to a sparse diet. In addition, the genes identified from de novo assembly could be utilized in differentiating Pashmina fiber from other fibers to avoid falsification at marketing practices.

scholarly journals MetaCoAG: Binning Metagenomic Contigs via Composition, Coverage and Assembly Graphs

2021 ◽  
Author(s):  
Vijini Mallawaarachchi ◽  
Yu Lin
Keyword(s):  
Microbial Communities ◽  
De Novo ◽  
State Of The Art ◽  
Genetic Material ◽  
Single Copy ◽  
Experimental Results ◽  
Marker Genes ◽  
High Quality ◽  
Second Best ◽  
Direct Use

ABSTRACTMetagenomics binning has allowed us to study and characterize various genetic material of different species and gain insights into microbial communities. While existing binning tools bin metagenomics de novo assemblies, they do not make use of the assembly graphs that produce such assemblies. Here we propose MetaCoAG, a tool that utilizes assembly graphs with the composition and coverage information to bin metagenomic contigs. MetaCoAG uses single-copy marker genes to estimate the number of initial bins, assigns contigs into bins iteratively and adjusts the number of bins dynamically throughout the binning process. Experimental results on simulated and real datasets demonstrate that MetaCoAG significantly outperforms state-of-the-art binning tools, producing more high-quality bins than the second-best tool, with an average median F1-score of 88.40%. To the best of our knowledge, MetaCoAG is the first stand-alone binning tool to make direct use of the assembly graph information. MetaCoAG is available at https://github.com/Vini2/MetaCoAG.

scholarly journals Evaluation of direct metagenomics and target enriched approaches for high-throughput sequencing of field rabies viruses

2019 ◽  
Vol 63 (4) ◽  
pp. 471-479
Author(s):  
Anna Orłowska ◽  
Ewelina Iwan ◽  
Marcin Smreczak ◽  
Jerzy Rola
Keyword(s):  
High Throughput ◽  
Deep Sequencing ◽  
High Throughput Sequencing ◽  
De Novo ◽  
High Reliability ◽  
Rna Extraction ◽  
Genetic Material ◽  
Target Enrichment ◽  
Red Foxes ◽  
Field Samples

AbstractIntroductionHigh-throughput sequencing (HTS) identifies random viral fragments in environmental samples metagenomically. High reliability gains it broad application in virus evolution, host-virus interaction, and pathogenicity studies. Deep sequencing of field samples with content of host genetic material and bacteria often produces insufficient data for metagenomics and must be preceded by target enrichment. The main goal of the study was the evaluation of HTS for complete genome sequencing of field-case rabies viruses (RABVs).Material and MethodsThe material was 23 RABVs isolated mainly from red foxes and one European bat lyssavirus-1 isolate propagated in neuroblastoma cells. Three methods of RNA isolation were tested for the direct metagenomics and RABV-enriched approaches. Deep sequencing was performed with a MiSeq sequencer (Illumina) and reagent v3 kit. Bioinformatics data were evaluated by Kraken and Centrifuge software and de novo assembly was done with metaSPAdes.ResultsTesting RNA extraction procedures revealed the deep sequencing scope superiority of the combined TRIzol/column method. This HTS methodology made it possible to obtain complete genomes of all the RABV isolates collected in the field. Significantly greater rates of RABV genome coverages (over 5,900) were obtained with RABV enrichment. Direct metagenomic studies sequenced the full length of 6 out of 16 RABV isolates with a medium coverage between 1 and 71.ConclusionDirect metagenomics gives the most realistic illustration of the field sample microbiome, but with low coverage. For deep characterisation of viruses, e.g. for spatial and temporal phylogeography during outbreaks, target enrichment is recommended as it covers sequences much more completely.

scholarly journals An Alternative Molecular View of Evolution: How DNA was Altered over Geological Time

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5081
Author(s):  
Fredric M. Menger
Keyword(s):  
Natural Selection ◽  
Complex Traits ◽  
Convergent Evolution ◽  
Common Ancestor ◽  
Cambrian Explosion ◽  
Natural Phenomena ◽  
Geological Time ◽  
Multiple Mutation ◽  
Total Lack ◽  
Physical Changes

Four natural phenomena are cited for their defiance of conventional neo-Darwinian analysis: human intelligence; cat domesticity; the Cambrian explosion; and convergent evolution. 1. Humans are now far more intelligent than needed in their hunting–gathering days >10,000 years ago. 2. Domestic cats evolved from wildcats via major genetic and physical changes, all occurring in less than 12,000 years. 3. The Cambrian explosion refers to the remarkable expansion of species that mystifies evolutionists, as there is a total lack of fossil evidence for precursors of this abundant new life. 4. Convergent evolution often involves formation of complex, multigene traits in two or more species that have no common ancestor. These four evolutionary riddles are discussed in terms of a proposed “preassembly” mechanism in which genes and gene precursors are collected silently and randomly over extensive time periods within huge non-coding sections of DNA. This is followed by epigenetic release of the genes, when the environment so allows, and by natural selection. In neo-Darwinism, macroevolution of complex traits involves multiple mutation/selections, with each of the resulting intermediates being more favorable to the species than the previous one. Preassembly, in contrast, invokes natural selection only after a partially or fully formed trait is already in place. Preassembly does not supplant neo-Darwinism but, instead, supplements neo-Darwinism in those important instances where the classical theory is wanting.

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