The Role of Context-Dependent Mutations in Generating Compositional and Codon Usage Bias in Grass Chloroplast DNA

2003 ◽  
Vol 56 (5) ◽  
pp. 616-629 ◽  
Author(s):  
Brian R. Morton
Keyword(s):  
Codon Usage ◽  
Chloroplast Dna ◽  
Codon Usage Bias ◽  
Context Dependent

scholarly journals Comparisons of Coding and Noncoding Sequences to infer the Origin of Codon usage Bias

2017 ◽  
Author(s):  
Prashant Mainali ◽  
Sobita Pathak
Keyword(s):  
Codon Usage ◽  
Codon Usage Bias ◽  
Gc Content ◽  
Mutation Bias ◽  
Translation Process ◽  
Noncoding Regions ◽  
Coding Regions ◽  
Synonymous Codons ◽  
Shed Light

ABSTRACTCodon usage bias is the preferential use of the subset of synonymous codons during translation. In this paper, the comparisons of normalized entropy and GC content between the sequence of coding regions of Escherichia coli k12 and noncoding regions (ncRNA, rRNA) of various organisms were done to shed light on the origin of the codon usage bias.The normalized entropy of the coding regions was found significantly higher than the noncoding regions, suggesting the role of the translation process in shaping codon usage bias. Further, when the position specific GC content of both coding and noncoding regions was analyzed, the GC2 content in coding regions was lower than GC1 and GC2 while in noncoding regions, the GC1, GC2, GC3 contents were approximately equal. This discrepancy is explained by the biased mutation coupled with the presence and absence of selection pressure. The accumulation of CG content occurs in the sequences due to mutation bias in DNA repair and recombination process. In noncoding regions, the mutation is harmful and thus, selected against while due to the degeneracy of codons in coding regions, a mutation in GC3 is neutral and hence, not selected. Thus, the accumulation of GC content occurs in coding regions, and thus codon usage bias occurs.

scholarly journals Context-Dependent Mutation Dynamics, Not Selection, Explains the Codon Usage Bias of Most Angiosperm Chloroplast Genes

2021 ◽  
Author(s):  
Brian R. Morton
Keyword(s):  
Codon Usage ◽  
Significant Role ◽  
Codon Usage Bias ◽  
Base Composition ◽  
Context Effects ◽  
Chloroplast Genes ◽  
Mutation Bias ◽  
Highly Expressed Genes ◽  
Context Dependent ◽  
Mutation Dynamics

AbstractTwo competing proposals about the degree to which selection affects codon usage of angiosperm chloroplast genes are examined. The first, based on observations that codon usage does not match expectations under the naïve assumption that base composition will be identical at all neutral sites, is that selection plays a significant role. The second is that codon usage is determined almost solely by mutation bias and drift, with selection influencing only one or two highly expressed genes, in particular psbA. First it is shown that, as a result of an influence of neighboring base composition on mutation dynamics, compositional biases are expected to be widely divergent at different sites in the absence of selection. The observed mutation properties are then used to predict expected neutral codon usage biases and to show that observed deviations from the naïve expectations are in fact expected given the context-dependent mutational dynamics. It is also shown that there is a match between the observed and expected codon usage when context effects are taken into consideration, with psbA being a notable exception. Overall, the data support the model that selection is not a widespread factor affecting the codon usage of angiosperm chloroplast genes and highlight the need to have an accurate model of mutational dynamics.

Codon usage bias affects α-amylase mRNA level by altering RNA stability and cytosine methylation patterns in Escherichia coli

2020 ◽  
Vol 66 (9) ◽  
pp. 521-528
Author(s):  
Yanzi Xing ◽  
Ruiqing Gong ◽  
Yichun Xu ◽  
Kunshan Liu ◽  
Mian Zhou
Keyword(s):  
Escherichia Coli ◽  
Codon Usage ◽  
Codon Usage Bias ◽  
Cytosine Methylation ◽  
Codon Optimization ◽  
Mrna Level ◽  
Protein Translation ◽  
Transcriptional Level ◽  
Translation Efficiency

Codon usage bias exists in almost every organism and is reported to regulate protein translation efficiency and folding. Besides translation, the preliminary role of codon usage bias on gene transcription has also been revealed in some eukaryotes such as Neurospora crassa. In this study, we took as an example the α-amylase-coding gene (amyA) and examined the role of codon usage bias in regulating gene expression in the typical prokaryote Escherichia coli. We confirmed the higher translation efficiency on codon-optimized amyA RNAs and found that the RNA level itself was also affected by codon optimization. The decreased RNA level was caused at least in part by altered mRNA stability at the post-transcriptional level. Codon optimization also altered the number of cytosine methylation sites. Examination on dcm knockouts suggested that cytosine methylation may be a minor mechanism adopted by codon bias to regulate gene RNA levels. More studies are required to verify the global effect of codon usage and to reveal its detailed mechanism on transcription.

scholarly journals Compositional Constraint Is the Key Force in Shaping Codon Usage Bias in Hemagglutinin Gene in H1N1 Subtype of InfluenzaAVirus

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Himangshu Deka ◽  
Supriyo Chakraborty
Keyword(s):  
Codon Usage ◽  
Codon Usage Bias ◽  
Synonymous Codon ◽  
Viral Evolution ◽  
Gc Content ◽  
H1n1 Subtype ◽  
Evolutionary Forces ◽  
Viral Hemagglutinin ◽  
Compositional Constraint

It is vital to unravel the codon usage bias in order to gain insights into the evolutionary forces dictating the viral evolution process. InfluenzaAvirus has attracted attention of many investigators over the years due to high mutation rate and being cross-specific shift operational in the viral genome. Several authors have reported that the codon usage bias is low in influenzaAviruses, citing mutational pressure as the decisive force shaping up the codon usage in these viruses. In this study, complete coding sequences of hemagglutinin genes for H1N1 subtype of influenzaAvirus have been explored for the possible codon usage bias acting upon these genes. The results indicate overall low bias with peaking ENC values. The GC content is found to be substantially low as against AT content in the silent codon sites. Significant correlations were observed in between the compositional parameters versus AT3, implying the possible role of the latter in shaping codon usage profile in the viral hemagglutinin. The data showed conspicuously that the sequences wereAredundant with most codons preferring nucleotideAover others in the third synonymous codon site. The results indicated the pivotal role of compositional pressure affecting codon usage in this virus.

Forming Impressions of Personality

2014 ◽  
Vol 45 (3) ◽  
pp. 153-163 ◽  
Author(s):  
Sanne Nauts ◽  
Oliver Langner ◽  
Inge Huijsmans ◽  
Roos Vonk ◽  
Daniël H. J. Wigboldus
Keyword(s):  
Impression Formation ◽  
Context Dependent

Asch’s seminal research on “Forming Impressions of Personality” (1946) has widely been cited as providing evidence for a primacy-of-warmth effect, suggesting that warmth-related judgments have a stronger influence on impressions of personality than competence-related judgments (e.g., Fiske, Cuddy, & Glick, 2007 ; Wojciszke, 2005 ). Because this effect does not fit with Asch’s Gestalt-view on impression formation and does not readily follow from the data presented in his original paper, the goal of the present study was to critically examine and replicate the studies of Asch’s paper that are most relevant to the primacy-of-warmth effect. We found no evidence for a primacy-of-warmth effect. Instead, the role of warmth was highly context-dependent, and competence was at least as important in shaping impressions as warmth.

scholarly journals Patterns of genome-wide codon usage bias in tobacco, tomato and potato

2021 ◽  
Vol 35 (1) ◽  
pp. 657-664
Author(s):  
Ali Mostafa Anwar ◽  
Maha Aljabri ◽  
Mohamed El-Soda
Keyword(s):  
Codon Usage ◽  
Codon Usage Bias ◽  
Genome Wide

scholarly journals Codon usage bias and environmental adaptation in microbial organisms

2021 ◽  
Author(s):  
Davide Arella ◽  
Maddalena Dilucca ◽  
Andrea Giansanti
Keyword(s):  
Codon Usage ◽  
Codon Usage Bias ◽  
Pathogenic Bacteria ◽  
Large Scale ◽  
Synonymous Codon ◽  
Principal Component ◽  
Gene Copy ◽  
Phenotypic Traits ◽  
Translational Efficiency ◽  
Microbial Organisms

AbstractIn each genome, synonymous codons are used with different frequencies; this general phenomenon is known as codon usage bias. It has been previously recognised that codon usage bias could affect the cellular fitness and might be associated with the ecology of microbial organisms. In this exploratory study, we investigated the relationship between codon usage bias, lifestyles (thermophiles vs. mesophiles; pathogenic vs. non-pathogenic; halophilic vs. non-halophilic; aerobic vs. anaerobic and facultative) and habitats (aquatic, terrestrial, host-associated, specialised, multiple) of 615 microbial organisms (544 bacteria and 71 archaea). Principal component analysis revealed that species with given phenotypic traits and living in similar environmental conditions have similar codon preferences, as represented by the relative synonymous codon usage (RSCU) index, and similar spectra of tRNA availability, as gauged by the tRNA gene copy number (tGCN). Moreover, by measuring the average tRNA adaptation index (tAI) for each genome, an index that can be associated with translational efficiency, we observed that organisms able to live in multiple habitats, including facultative organisms, mesophiles and pathogenic bacteria, are characterised by a reduced translational efficiency, consistently with their need to adapt to different environments. Our results show that synonymous codon choices might be under strong translational selection, which modulates the choice of the codons to differently match tRNA availability, depending on the organism’s lifestyle needs. To our knowledge, this is the first large-scale study that examines the role of codon bias and translational efficiency in the adaptation of microbial organisms to the environment in which they live.

scholarly journals Genome-Wide Analysis of Codon Usage Patterns of SARS-CoV-2 Virus Reveals Global Heterogeneity of COVID-19

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 912
Author(s):  
Saadullah Khattak ◽  
Mohd Ahmar Rauf ◽  
Qamar Zaman ◽  
Yasir Ali ◽  
Shabeen Fatima ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Codon Usage ◽  
Codon Usage Bias ◽  
Geographic Location ◽  
Mutation Pressure ◽  
Genome Wide ◽  
Margin Of Error ◽  
Usage Patterns ◽  
Causative Agents ◽  
Virus Genomes

The ongoing outbreak of coronavirus disease COVID-19 is significantly implicated by global heterogeneity in the genome organization of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The causative agents of global heterogeneity in the whole genome of SARS-CoV-2 are not well characterized due to the lack of comparative study of a large enough sample size from around the globe to reduce the standard deviation to the acceptable margin of error. To better understand the SARS-CoV-2 genome architecture, we have performed a comprehensive analysis of codon usage bias of sixty (60) strains to get a snapshot of its global heterogeneity. Our study shows a relatively low codon usage bias in the SARS-CoV-2 viral genome globally, with nearly all the over-preferred codons’ A.U. ended. We concluded that the SARS-CoV-2 genome is primarily shaped by mutation pressure; however, marginal selection pressure cannot be overlooked. Within the A/U rich virus genomes of SARS-CoV-2, the standard deviation in G.C. (42.91% ± 5.84%) and the GC3 value (30.14% ± 6.93%) points towards global heterogeneity of the virus. Several SARS-CoV-2 viral strains were originated from different viral lineages at the exact geographic location also supports this fact. Taking all together, these findings suggest that the general root ancestry of the global genomes are different with different genome’s level adaptation to host. This research may provide new insights into the codon patterns, host adaptation, and global heterogeneity of SARS-CoV-2.

Sign in / Sign up

Export Citation Format

Share Document