scholarly journals Contrasting Codon Usage Patterns and Purifying Selection at the Mating Locus in Putatively Asexual Alternaria Fungal Species

PLoS ONE ◽  
2011 ◽  
Vol 6 (5) ◽  
pp. e20083 ◽  
Author(s):  
Jane E. Stewart ◽  
Masato Kawabe ◽  
Zaid Abdo ◽  
Tsutomu Arie ◽  
Tobin L. Peever
Keyword(s):  
Codon Usage ◽  
Purifying Selection ◽  
Fungal Species ◽  
Usage Patterns

scholarly journals Weak selection on synonymous codons substantially inflates dN/dS estimates in bacteria

2021 ◽  
Vol 118 (20) ◽  
pp. e2023575118
Author(s):  
Shakibur Rahman ◽  
Sergei L. Kosakovsky Pond ◽  
Andrew Webb ◽  
Jody Hey
Keyword(s):  
Codon Usage ◽  
Synonymous Codon ◽  
Purifying Selection ◽  
Synonymous Substitution ◽  
Weak Selection ◽  
Codon Model ◽  
Synonymous Substitutions ◽  
Synonymous Codons ◽  
Usage Patterns

Synonymous codon substitutions are not always selectively neutral as revealed by several types of analyses, including studies of codon usage patterns among genes. We analyzed codon usage in 13 bacterial genomes sampled from across a large order of bacteria, Enterobacterales, and identified presumptively neutral and selected classes of synonymous substitutions. To estimate substitution rates, given a neutral/selected classification of synonymous substitutions, we developed a flexible dN/dS substitution model that allows multiple classes of synonymous substitutions. Under this multiclass synonymous substitution (MSS) model, the denominator of dN/dS includes only the strictly neutral class of synonymous substitutions. On average, the value of dN/dS under the MSS model was 80% of that under the standard codon model in which all synonymous substitutions are assumed to be neutral. The indication is that conventional dN/dS analyses overestimate these values and thus overestimate the frequency of positive diversifying selection and underestimate the strength of purifying selection. To quantify the strength of selection necessary to explain this reduction, we developed a model of selected compensatory codon substitutions. The reduction in synonymous substitution rate, and thus the contribution that selection makes to codon bias variation among genes, can be adequately explained by very weak selection, with a mean product of population size and selection coefficient, Ns=0.8.

scholarly journals Comparative analysis of transcriptomic data shows the effects of multiple evolutionary selection processes on codon usage in Marsupenaeus japonicus and Marsupenaeus pulchricaudatus

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Panpan Wang ◽  
Yong Mao ◽  
Yongquan Su ◽  
Jun Wang
Keyword(s):  
Gene Expression ◽  
Codon Usage ◽  
Codon Bias ◽  
Purifying Selection ◽  
Marsupenaeus Japonicus ◽  
Bias Analysis ◽  
Codon Preference ◽  
Optimal Codons ◽  
Usage Patterns ◽  
Usage Analysis

Abstract Background Kuruma shrimp, a major commercial shrimp species in the world, has two cryptic or sibling species, Marsupenaeus japonicus and Marsupenaeus pulchricaudatus. Codon usage analysis would contribute to our understanding of the genetic and evolutionary characteristics of the two Marsupenaeus species. In this study, we analyzed codon usage and related indices using coding sequences (CDSs) from RNA-seq data. Results Using CodonW 1.4.2 software, we performed the codon bias analysis of transcriptomes obtained from hepatopancreas tissues, which indicated weak codon bias. Almost all parameters had similar correlations for both species. The gene expression level (FPKM) was negatively correlated with A/T3s. We determined 12 and 14 optimal codons for M. japonicus and M. pulchricaudatus, respectively, and all optimal codons have a C/G-ending. The two Marsupenaeus species had different usage frequencies of codon pairs, which contributed to further analysis of transcriptional differences between them. Orthologous genes that underwent positive selection (ω > 1) had a higher correlation coefficient than that of experienced purifying selection (ω < 1). Parity Rule 2 (PR2) and effective number of codons (ENc) plot analysis showed that the codon usage patterns of both species were influenced by both mutations and selection. Moreover, the average observed ENc value was lower than the expected value for both species, suggesting that factors other than GC may play roles in these phenomena. The results of multispecies clustering based on codon preference were consistent with traditional classification. Conclusions This study provides a relatively comprehensive understanding of the correlations among codon usage bias, gene expression, and selection pressures of CDSs for M. japonicus and M. pulchricaudatus. The genetic evolution was driven by mutations and selection pressure. Moreover, the results point out new insights into the specificities and evolutionary characteristics of the two Marsupenaeus species.

scholarly journals Comparative analysis of the codon usage patterns in two closely related Marsupenaeus species based on comparative transcriptomics

2020 ◽  
Author(s):  
Panpan Wang ◽  
Yong Mao ◽  
Yongquan Su ◽  
Jun Wang
Keyword(s):  
Codon Usage ◽  
Purifying Selection ◽  
Evolutionary Trends ◽  
Bias Analysis ◽  
Codon Preference ◽  
Plot Analysis ◽  
Optimal Codons ◽  
Traditional Classification ◽  
Usage Patterns ◽  
Codon Pairs

Abstract Background: Marsupenaeus japonicus, a major commercial shrimp species in the world, has two cryptic or sibling species, Marsupenaeus japonicus and Marsupenaeus pulchricaudatus. Due to the lack of genomic information, little is known about the correlations among codon usage bias, gene expression, and evolutionary trends in Marsupenaeus orthologs.Results: Using the CodonW 1.4.2 software, we performed the codon bias analysis of two Marsupenaeus species transcriptomes. The average contents of GC and ENc were 51.61% and 52.1 for VI (M. japonicus), 51.54% and 52.22 for VII (M. pulchricaudatus), respectively. Parity Rule 2 (PR2) plot analysis showed that purines (A and G) were used more frequently than pyrimidines (C and T) in two Marsupenaeus species. The average ENc value was 52.1 and 52.22 for M. japonicus and M. pulchricaudatus, respectively. Overall, orthologous genes that underwent positive selection (ω > 1) had a higher correlation coefficient than that experienced purifying selection (ω < 1). In M. japonicus, the relationships were highly significant positive about Axis 1 and A3, T3 and ENc (p < 0.01). However, all relationships in M. pulchricaudatus were the opposite. We determined 12 and 14 optimal codons for M. japonicus and M. pulchricaudatus, respectively. Two Marsupenaeus species had 31 different codon pairs. The results of multi-species clustering based on codon preference were consistent with traditional classification. Conclusions: We characterized the codon usage patterns of the two Marsupenaeus species and the evolutionary trends in Marsupenaeus orthologs, which provides new insights into the genetic divergence and the phylogenetic relationships of two Marsupenaeus species.

Analysis of Codon Usage Patterns in the Human Papillomavirus Oncogenes

2020 ◽  
Vol 15 ◽  
Author(s):  
Myeongji Cho ◽  
Hayeon Kim ◽  
Mikyeong Je ◽  
Hyeon S. Son
Keyword(s):  
Human Papillomavirus ◽  
High Risk ◽  
Codon Usage ◽  
Selection Pressure ◽  
Synonymous Codon ◽  
Purifying Selection ◽  
Hpv Infection ◽  
Nucleotide Composition ◽  
Usage Patterns ◽  
E6 And E7

Background: Persistent high-risk genital human papillomavirus (HPV) infection is a major cause of cervical cancer in women. The products of the viral transforming genes E6 and E7 in the high-risk HPVs are known to be similar in their amino acid composition and structure. We performed a comparative analysis of codon usage patterns in the E6 and E7 genes of HPVs. Methods: The E6 and E7 gene sequences of eight HPV subtypes were analyzed to determine their nucleotide composition, relative synonymous codon usage (RSCU), effective number of codons (ENC), neutrality, genetic variability, selection pressure, and codon adaptation index (CAI). Additionally, a correspondence analysis (CoA) was performed. Results: The analysis to determine the effects of differences in composition on the codon usage patterns revealed that there may be usage bias for ‘A’ nucleotides. This was consistent with the results of the RSCU analysis, which demonstrated that the selection of A/T-rich patterns and the preference for A/T-ended codons in HPVs are influenced by compositional constraints. Moreover, the results reveal that selection pressure plays an important role in the CoA results for the RSCU values, Tajima’s D tests, and neutrality tests. Conclusion: The results of this study are consistent with previous findings that most papillomavirus genes are under purifying selection pressure, which limits changes to the encoded proteins. Natural selection and mutation pressures resulting in changes in the nucleotide composition and codon usage bias in the two tumor genes of HPV act differently during the evolution of the HPV subtype; thus, throughout the viral life cycle, HPV can constantly evolve to adapt to a new environment.

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.

Analysis of synonymous codon usage inShigella flexneri2a strain 301 and otherShigellaandEscherichia colistrains

2011 ◽  
Vol 57 (12) ◽  
pp. 1016-1023 ◽  
Author(s):  
Xue Lian Luo ◽  
Jian Guo Xu ◽  
Chang Yun Ye
Keyword(s):  
Codon Usage ◽  
Codon Usage Bias ◽  
Synonymous Codon ◽  
Shigella Flexneri ◽  
Synonymous Codon Usage ◽  
Codon Usage Pattern ◽  
Mutational Pressure ◽  
E Coli ◽  
Shigella Flexneri 2A ◽  
Usage Patterns

In this study, we analysed synonymous codon usage in Shigella flexneri 2a strain 301 (Sf301) and performed a comparative analysis of synonymous codon usage patterns in Sf301 and other strains of Shigella and Escherichia coli . Although there was a significant variety in codon usage bias among different Sf301 genes, there was a slight but observable codon usage bias that could primarily be attributable to mutational pressure and translational selection. In addition, the relative abundance of dinucleotides in Sf301 was observed to be independent of the overall base composition but was still caused by differential mutational pressure; this also shaped codon usage. By comparing the relative synonymous codon usage values across different Shigella and E. coli strains, we suggested that the synonymous codon usage pattern in the Shigella genomes was strain specific. This study represents a comprehensive analysis of Shigella codon usage patterns and provides a basic understanding of the mechanisms underlying codon usage bias.

scholarly journals Analysis of Codon Usage Patterns in Giardia duodenalis Based on Transcriptome Data from GiardiaDB

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1169
Author(s):  
Xin Li ◽  
Xiaocen Wang ◽  
Pengtao Gong ◽  
Nan Zhang ◽  
Xichen Zhang ◽  
...  
Keyword(s):  
Codon Usage ◽  
Genetic Manipulation ◽  
Molecular Genetic ◽  
Gc Content ◽  
Giardia Duodenalis ◽  
Codon Usage Pattern ◽  
Protein Size ◽  
New Genes ◽  
Optimal Codons ◽  
Usage Patterns

Giardia duodenalis, a flagellated parasitic protozoan, the most common cause of parasite-induced diarrheal diseases worldwide. Codon usage bias (CUB) is an important evolutionary character in most species. However, G. duodenalis CUB remains unclear. Thus, this study analyzes codon usage patterns to assess the restriction factors and obtain useful information in shaping G. duodenalis CUB. The neutrality analysis result indicates that G. duodenalis has a wide GC3 distribution, which significantly correlates with GC12. ENC-plot result—suggesting that most genes were close to the expected curve with only a few strayed away points. This indicates that mutational pressure and natural selection played an important role in the development of CUB. The Parity Rule 2 plot (PR2) result demonstrates that the usage of GC and AT was out of proportion. Interestingly, we identified 26 optimal codons in the G. duodenalis genome, ending with G or C. In addition, GC content, gene expression, and protein size also influence G. duodenalis CUB formation. This study systematically analyzes G. duodenalis codon usage pattern and clarifies the mechanisms of G. duodenalis CUB. These results will be very useful to identify new genes, molecular genetic manipulation, and study of G. duodenalis evolution.

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