scholarly journals Genome size and genomic GC content evolution in the miniature genome-sized family Lentibulariaceae

2014 ◽  
Vol 203 (1) ◽  
pp. 22-28 ◽  
Author(s):  
Adam Veleba ◽  
Petr Bureš ◽  
Lubomír Adamec ◽  
Petr Šmarda ◽  
Ivana Lipnerová ◽  
...  
Keyword(s):  
Genome Size ◽  
Gc Content ◽  
Genomic Gc Content

scholarly journals Substantial intraspecific genome size variation in golden-brown algae and its phenotypic consequences

2020 ◽  
Vol 126 (6) ◽  
pp. 1077-1087
Author(s):  
Dora Čertnerová ◽  
Pavel Škaloud
Keyword(s):  
Growth Rate ◽  
Genome Size ◽  
Cell Size ◽  
Nuclear Dna ◽  
Gc Content ◽  
Size Variation ◽  
Nuclear Dna Content ◽  
Genome Size Variation ◽  
Adaptive Consequences ◽  
Genomic Gc Content

Abstract Background and Aims While nuclear DNA content variation and its phenotypic consequences have been well described for animals, vascular plants and macroalgae, much less about this topic is known regarding unicellular algae and protists in general. The dearth of data is especially pronounced when it comes to intraspecific genome size variation. This study attempts to investigate the extent of intraspecific variability in genome size and its adaptive consequences in a microalgal species. Methods Propidium iodide flow cytometry was used to estimate the absolute genome size of 131 strains (isolates) of the golden-brown alga Synura petersenii (Chrysophyceae, Stramenopiles), identified by identical internal transcribed spacer (ITS) rDNA barcodes. Cell size, growth rate and genomic GC content were further assessed on a sub-set of strains. Geographic location of 67 sampling sites across the Northern hemisphere was used to extract climatic database data and to evaluate the ecogeographical distribution of genome size diversity. Key Results Genome size ranged continuously from 0.97 to 2.02 pg of DNA across the investigated strains. The genome size was positively associated with cell size and negatively associated with growth rate. Bioclim variables were not correlated with genome size variation. No clear trends in the geographical distribution of strains of a particular genome size were detected, and strains of different genome size occasionally coexisted at the same locality. Genomic GC content was significantly associated only with genome size via a quadratic relationship. Conclusions Genome size variability in S. petersenii was probably triggered by an evolutionary mechanism operating via gradual changes in genome size accompanied by changes in genomic GC content, such as, for example, proliferation of transposable elements. The variation was reflected in cell size and relative growth rate, possibly with adaptive consequences.

scholarly journals Evolution of genome size and genomic GC content in carnivorous holokinetics (Droseraceae)

2016 ◽  
Vol 119 (3) ◽  
pp. 409-416 ◽  
Author(s):  
Adam Veleba ◽  
Petr Šmarda ◽  
František Zedek ◽  
Lucie Horová ◽  
Jakub Šmerda ◽  
...  
Keyword(s):  
Genome Size ◽  
Gc Content ◽  
Genomic Gc Content

scholarly journals Coupling Between Protein Level Selection and Codon Usage Optimization in the Evolution of Bacteria and Archaea

mBio ◽  
2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Wenqi Ran ◽  
David M. Kristensen ◽  
Eugene V. Koonin
Keyword(s):  
Codon Usage ◽  
Protein Level ◽  
Codon Usage Bias ◽  
Protein Sequence ◽  
Gc Content ◽  
Protein Sequences ◽  
Microbial Evolution ◽  
Fine Tuning ◽  
Selection For ◽  
Genomic Gc Content

ABSTRACT The relationship between the selection affecting codon usage and selection on protein sequences of orthologous genes in diverse groups of bacteria and archaea was examined by using the Alignable Tight Genome Clusters database of prokaryote genomes. The codon usage bias is generally low, with 57.5% of the gene-specific optimal codon frequencies (F opt ) being below 0.55. This apparent weak selection on codon usage contrasts with the strong purifying selection on amino acid sequences, with 65.8% of the gene-specific dN/dS ratios being below 0.1. For most of the genomes compared, a limited but statistically significant negative correlation between F opt and dN/dS was observed, which is indicative of a link between selection on protein sequence and selection on codon usage. The strength of the coupling between the protein level selection and codon usage bias showed a strong positive correlation with the genomic GC content. Combined with previous observations on the selection for GC-rich codons in bacteria and archaea with GC-rich genomes, these findings suggest that selection for translational fine-tuning could be an important factor in microbial evolution that drives the evolution of genome GC content away from mutational equilibrium. This type of selection is particularly pronounced in slowly evolving, “high-status” genes. A significantly stronger link between the two aspects of selection is observed in free-living bacteria than in parasitic bacteria and in genes encoding metabolic enzymes and transporters than in informational genes. These differences might reflect the special importance of translational fine-tuning for the adaptability of gene expression to environmental changes. The results of this work establish the coupling between protein level selection and selection for translational optimization as a distinct and potentially important factor in microbial evolution. IMPORTANCE Selection affects the evolution of microbial genomes at many levels, including both the structure of proteins and the regulation of their production. Here we demonstrate the coupling between the selection on protein sequences and the optimization of codon usage in a broad range of bacteria and archaea. The strength of this coupling varies over a wide range and strongly and positively correlates with the genomic GC content. The cause(s) of the evolution of high GC content is a long-standing open question, given the universal mutational bias toward AT. We propose that optimization of codon usage could be one of the key factors that determine the evolution of GC-rich genomes. This work establishes the coupling between selection at the level of protein sequence and at the level of codon choice optimization as a distinct aspect of genome evolution.

scholarly journals Selection Maintains Low Genomic GC Content in Marine SAR11 Lineages

2015 ◽  
Vol 32 (10) ◽  
pp. 2738-2748 ◽  
Author(s):  
Haiwei Luo ◽  
Luke R. Thompson ◽  
Ulrich Stingl ◽  
Austin L. Hughes
Keyword(s):  
Gc Content ◽  
Genomic Gc Content

scholarly journals Comparative analysis reveals within-population genome size variation in a rotifer is driven by large genomic elements with highly abundant satellite DNA repeat elements

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
C. P. Stelzer ◽  
J. Blommaert ◽  
A. M. Waldvogel ◽  
M. Pichler ◽  
B. Hecox-Lea ◽  
...  
Keyword(s):  
Genome Size ◽  
Satellite Dna ◽  
Gc Content ◽  
Size Variation ◽  
Isolated Populations ◽  
Genome Size Variation ◽  
Variable Regions ◽  
Geographic Population ◽  
Genome Size Evolution ◽  
Size Evolution

Abstract Background Eukaryotic genomes are known to display an enormous variation in size, but the evolutionary causes of this phenomenon are still poorly understood. To obtain mechanistic insights into such variation, previous studies have often employed comparative genomics approaches involving closely related species or geographically isolated populations within a species. Genome comparisons among individuals of the same population remained so far understudied—despite their great potential in providing a microevolutionary perspective to genome size evolution. The rotifer Brachionus asplanchnoidis represents one of the most extreme cases of within-population genome size variation among eukaryotes, displaying almost twofold variation within a geographic population. Results Here, we used a whole-genome sequencing approach to identify the underlying DNA sequence differences by assembling a high-quality reference genome draft for one individual of the population and aligning short reads of 15 individuals from the same geographic population including the reference individual. We identified several large, contiguous copy number variable regions (CNVs), up to megabases in size, which exhibited striking coverage differences among individuals, and whose coverage overall scaled with genome size. CNVs were of remarkably low complexity, being mainly composed of tandemly repeated satellite DNA with only a few interspersed genes or other sequences, and were characterized by a significantly elevated GC-content. CNV patterns in offspring of two parents with divergent genome size and CNV patterns in several individuals from an inbred line differing in genome size demonstrated inheritance and accumulation of CNVs across generations. Conclusions By identifying the exact genomic elements that cause within-population genome size variation, our study paves the way for studying genome size evolution in contemporary populations rather than inferring patterns and processes a posteriori from species comparisons.

scholarly journals Molecular Characterization and Antimicrobial Susceptibilities of Nocardia Species Isolated from the Soil; A Comparison with Species Isolated from Humans

2020 ◽  
Vol 8 (6) ◽  
pp. 900
Author(s):  
Gema Carrasco ◽  
Sara Monzón ◽  
María San Segundo ◽  
Enrique García ◽  
Noelia Garrido ◽  
...  
Keyword(s):  
16S Rrna ◽  
Topoisomerase Ii ◽  
Gc Content ◽  
Amino Acid Identity ◽  
Beta Lactams ◽  
Nocardia Species ◽  
Antimicrobial Susceptibilities ◽  
The Difference ◽  
Subunit B ◽  
Genomic Gc Content

Nocardia species, one of the most predominant Actinobacteria of the soil microbiota, cause infection in humans following traumatic inoculation or inhalation. The identification, typing, phylogenetic relationship and antimicrobial susceptibilities of 38 soil Nocardia strains from Lara State, Venezuela, were studied by 16S rRNA and gyrB (subunit B of topoisomerase II) genes, multilocus sequence analysis (MLSA), whole-genome sequencing (WGS), and microdilution. The results were compared with those for human strains. Just seven Nocardia species with one or two strains each, except for Nocardia cyriacigeorgica with 29, were identified. MLSA confirmed the species assignments made by 16S rRNA and gyrB analyses (89.5% and 71.0% respectively), and grouped each soil strain with its corresponding reference and clinical strains, except for 19 N. cyriacigeorgica strains found at five locations which grouped into a soil-only cluster. The soil strains of N. cyriacigeorgica showed fewer gyrB haplotypes than the examined human strains (13 vs. 17) but did show a larger number of gyrB SNPs (212 vs. 77). Their susceptibilities to antimicrobials were similar except for beta-lactams, fluoroquinolones, minocycline, and clarithromycin, with the soil strains more susceptible to the first three (p ≤ 0.05). WGS was performed on four strains belonging to the soil-only cluster and on two outside it, and the results compared with public N. cyriacigeorgica genomes. The average nucleotide/amino acid identity, in silico genome-to-genome hybridization similarity, and the difference in the genomic GC content, suggest that some strains of the soil-only cluster may belong to a novel subspecies or even a new species (proposed name Nocardia venezuelensis).

scholarly journals Marsupial chromosome DNA content and genome size assessed from flow karyotypes: invariable low autosomal GC content

2018 ◽  
Vol 5 (8) ◽  
pp. 171539 ◽  
Author(s):  
Fumio Kasai ◽  
Patricia C. M. O'Brien ◽  
Jorge C. Pereira ◽  
Malcolm A. Ferguson-Smith
Keyword(s):  
Genome Size ◽  
Dna Content ◽  
Chromosome Painting ◽  
Gc Content ◽  
Tammar Wallaby ◽  
Individual Chromosome ◽  
Tasmanian Devil ◽  
Marsupial Species ◽  
Cross Species Chromosome Painting ◽  
High Level

Extensive chromosome homologies revealed by cross-species chromosome painting between marsupials have suggested a high level of genome conservation during evolution. Surprisingly, it has been reported that marsupial genome sizes vary by more than 1.2 Gb between species. We have shown previously that individual chromosome sizes and GC content can be measured in flow karyotypes, and have applied this method to compare four marsupial species. Chromosome sizes and GC content were calculated for the grey short-tailed opossum (2 n = 18), tammar wallaby (2 n = 16), Tasmanian devil (2 n = 14) and fat-tailed dunnart (2 n = 14), resulting in genome sizes of 3.41, 3.31, 3.17 and 3.25 Gb, respectively. The findings under the same conditions allow a comparison between the four species, indicating that the genomes of these four species are 1–8% larger than human. We show that marsupial genomes are characterized by a low GC content invariable between autosomes and distinct from the higher GC content of the marsupial × chromosome.

scholarly journals Draft Genome Sequence of Rummeliibacillus sp. Strain TYF005, a Physiologically Recalcitrant Bacterium with High Ethanol and Salt Tolerance Isolated from Spoilage Vinegar

2019 ◽  
Vol 8 (31) ◽  
Author(s):  
Min Li ◽  
Yao Li ◽  
Xiaojun Fan ◽  
Yuhong Qin ◽  
Yongji He ◽  
...  
Keyword(s):  
Salt Tolerance ◽  
Genome Size ◽  
Genome Sequence ◽  
Draft Genome ◽  
Gc Content ◽  
Thermophilic Bacterium ◽  
Draft Genome Sequence ◽  
Content Type ◽  
High Ethanol

Rummeliibacillus sp. strain TYF005 is a thermophilic bacterium with high ethanol (8% vol/vol) and salt (13% wt/vol) tolerance that was isolated from spoilage vinegar. Here, we report the draft genome sequence of this strain, which has 117 scaffolds with a total genome size of 3.7 Mb and a 34.4% GC content.

scholarly journals Diversity in genome size and GC content shows adaptive potential in orchids and is closely linked to partial endoreplication, plant life‐history traits and climatic conditions

2019 ◽  
Vol 224 (4) ◽  
pp. 1642-1656 ◽  
Author(s):  
Pavel Trávníček ◽  
Martin Čertner ◽  
Jan Ponert ◽  
Zuzana Chumová ◽  
Jana Jersáková ◽  
...  
Keyword(s):  
Life History ◽  
Genome Size ◽  
Life History Traits ◽  
Gc Content ◽  
Climatic Conditions ◽  
Adaptive Potential ◽  
Plant Life
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