Search

Molnupiravir, an oral direct‐acting antiviral effective in vitro against SARS‐CoV‐2, has been largely employed during the COVID‐19 pandemic, since December 2021. After marketing and widespread usage, a progressive increase in SARS‐CoV‐2 lineages characterized by a higher transition/transversion ratio, a characteristic signature of molnupiravir action, appeared in the Global Initiative on Sharing All Influenza Data (GISAID) and International Nucleotide Sequence Database Collaboration (INSDC) databases. Here, we assessed the drug effects by SARS‐CoV‐2 whole‐genome sequencing on 38 molnupiravir‐treated persistently positive COVID‐19 outpatients tested before and after treatment. Seventeen tixagevimab/cilgavimab‐treated outpatients served as controls. Mutational analyses confirmed that SARS‐CoV‐2 exhibits an increased transition/transversion ratio seven days after initiation of molnupiravir. Moreover we observed an increased G‐>A ratio compared to controls, which was not related to apolipoprotein B mRNAediting enzyme, catalytic polypeptide‐like (APOBEC) activity. In addition, we demonstrated for the first time an increased diversity and complexity of the viral quasispecies. [ABSTRACT FROM AUTHOR]

Short tandem repeats located 5ʹ prime to the β-globin gene, have been observed to be in linkage disequilibrium with the HbS allele, and thought to affect the severity of sickle cell disease. Here, we report on new mutants within the HBG2 region that may impact sickle cell disease. To determine the cis-acting elements microsatellites, indels and single nucleotide polymorphisms (SNPs), within the HBG2 region by sequencing, in subjects with sickle cell disease. The case–control study was located at the Center for Clinical Genetics, Sickle cell unit, Korle–Bu Teaching Hospital. A questionnaire was used for demographic data and clinical information. Hematological profile (red blood cell, white blood cell, platelet, hemoglobin and mean corpuscular volume) were assessed in 83 subjects. A set of 45 samples comprising amplified DNA on the HBG2 gene from HbSS (22), HbSC (17) and 6 controls (HbAA) were sequenced. Differences in the microsatellite region between sickle cell disease (SCD) (HbSS and HbSC) genotypes and control subjects were identified by counting and assessed by Chi-square analysis. Red blood cells, hematocrit, platelets, white blood cells and hemoglobin indices differed in genotypic groups. HbSS subjects were affirmed to have severer hemolytic anemia than HbSC subjects. Two indels (T1824 and C905) were seen in both SS and SC genotypes. Two peculiar SNPs: G:T1860 (transition) and A:G1872 transversions were found within the HBG2 gene that were significantly associated with the HbSS genotype (Fisher's exact test, p = 0.006) and HbS allele respectively (Fisher's exact test, p = 0.006). Cis-acting elements in HbSS and HbSC were different and may contribute to the phenotype seen in the disease state. [ABSTRACT FROM AUTHOR]

Introduction. The propensity of nucleotide bases to form pairs, causes folding and the formation of secondary structure in the RNA. Therefore, purine (R): pyrimidine (Y) base-pairing is vital to maintain uniform lateral dimension in RNA secondary structure. Transversions or base substitutions between R and Y bases, are more detrimental to the stability of RNA secondary structure, than transitions derived from substitutions between A andGor C and T. The study of transversion and transition base substitutions is important to understand evolutionary mechanisms of RNA secondary structure in the 50 and 30 untranslated (UTR) regions of SARS-CoV-2. In this work, we carried out comparative analysis of transition and transversion base substitutions in the stem and loop regions of RNA secondary structure of SARS-CoV-2. Methods. We have considered the experimentally determined and well documented stem and loop regions of 50 and 30 UTR regions of SARS-CoV-2 for base substitution analysis. The secondary structure comprising of stem and loop regions were visualized using the RNAfold web server. The GISAID repository was used to extract base sequence alignment of the UTR regions. Python scripts were developed for comparative analysis of transversion and transition frequencies in the stem and the loop regions. Results. The results of base substitution analysis revealed a higher transition (ti) to transversion (tv) ratio (ti/tv) in the stem region of UTR of RNA secondary structure of SARS-CoV-2 reported during the early stage of the pandemic. The higher ti/tv ratio in the stem region suggested the influence of secondary structure in selecting the pattern of base substitutions. This differential pattern of ti/tv values between stem and loop regions was not observed among the Delta and Omicron variants that dominated the later stage of the pandemic. It is noteworthy that the ti/tv values in the stem and loop regions were similar among the later dominant Delta and Omicron variant strains which is to be investigated to understand the rapid evolution and global adaptation of SARS-CoV-2. Conclusion. Our findings implicate the lower frequency of transversions than the transitions in the stem regions of UTRs of SARS-CoV-2. The RNA secondary structures are associated with replication, translation, and packaging, further investigations are needed to understand these base substitutions across different variants of SARS-CoV-2 [ABSTRACT FROM AUTHOR]

Transfer ribonucleic acids (tRNAs) are small non-coding ribonucleic acids that decode messenger RNA sequences and are directly involved in protein synthesis by carrying amino acids to the ribosome. However, the chloroplast genome needs to better understand tRNAs' phylogeny and evolutionary mechanisms. The present study aimed to delineate the novel structural variations and evolutionary characteristics in the chloroplast genome tRNAs of thirty-six Sapindaceae species. Several novel tRNA structures were identified in the Sapindaceae chloroplast genome. The length of tRNAs ranged from 64 to 93 nucleotides, containing 27–29 anticodons. Pair-wise sequence results showed the conserved nucleotide consensus sequence U-U-C-x-A–x-U in Sapindaceae. The structural analysis revealed that, except for a few tRNAs (tRNAHis, tRNAGly, tRNAThr, tRNAPhe, tRNATry, tRNAMet, and tRNAPro), all contained a G nucleotide at the 1st position in the acceptor's arm of tRNAs secondary structure. The rate of transition and transversion of tRNAs are Iso-acceptor-specific. Evolutionary analysis revealed that Sapindaceae chloroplast tRNAs might have evolved polyphyletically with a high percentage of gene loss. Phylogenetic analysis revealed that the chloroplast genome's tRNAs evolved from several common ancestors. At the same time, tRNAVal and tRNAMet appear to be the ancestral tRNAs that underwent duplication diversification to give rise to other tRNAs. Our findings will help us understand the evolution of the tRNA and suggest a key role in chloroplast tRNA biology. [ABSTRACT FROM AUTHOR]

Introduction The propensity of nucleotide bases to form pairs, causes folding and the formation of secondary structure in the RNA. Therefore, purine (R): pyrimidine (Y) base-pairing is vital to maintain uniform lateral dimension in RNA secondary structure. Transversions or base substitutions between R and Y bases, are more detrimental to the stability of RNA secondary structure, than transitions derived from substitutions between A and G or C and T. The study of transversion and transition base substitutions is important to understand evolutionary mechanisms of RNA secondary structure in the 5′ and 3′ untranslated (UTR) regions of SARS-CoV-2. In this work, we carried out comparative analysis of transition and transversion base substitutions in the stem and loop regions of RNA secondary structure of SARS-CoV-2. Methods We have considered the experimentally determined and well documented stem and loop regions of 5′ and 3′ UTR regions of SARS-CoV-2 for base substitution analysis. The secondary structure comprising of stem and loop regions were visualized using the RNAfold web server. The GISAID repository was used to extract base sequence alignment of the UTR regions. Python scripts were developed for comparative analysis of transversion and transition frequencies in the stem and the loop regions. Results The results of base substitution analysis revealed a higher transition (ti) to transversion (tv) ratio (ti/tv) in the stem region of UTR of RNA secondary structure of SARS-CoV-2 reported during the early stage of the pandemic. The higher ti/tv ratio in the stem region suggested the influence of secondary structure in selecting the pattern of base substitutions. This differential pattern of ti/tv values between stem and loop regions was not observed among the Delta and Omicron variants that dominated the later stage of the pandemic. It is noteworthy that the ti/tv values in the stem and loop regions were similar among the later dominant Delta and Omicron variant strains which is to be investigated to understand the rapid evolution and global adaptation of SARS-CoV-2. Conclusion Our findings implicate the lower frequency of transversions than the transitions in the stem regions of UTRs of SARS-CoV-2. The RNA secondary structures are associated with replication, translation, and packaging, further investigations are needed to understand these base substitutions across different variants of SARS-CoV-2.

Pantoea is an opportunistic bacterium primarily involved in nosocomial infections, impacting newborns and immunocompromised patients. The study aimed to investigate the virulence factor of Pantoea in urinary tract infections in hospitals in Al-Nasiriyah City, Iraq. The outcome appeared that 22 isolates out of 100 urine samples had been confirmed as Pantoea species by VITEK-2. RcsA and hrpA genes were detected using conventional Polymerase Chain Reactions (PCR) and specific primers. The distribution of rcsA and hrpA was 40.9% and 59.1% respectively. The Pantoea species were distributed according to age, gender, and ABO blood groups. The percentage was 72.3% for ages 40-70, and females recorded 54.5% more than males. Individuals with the A blood group had a higher percentage (50%) than other blood groups; there were two types of variations (Transversion and Transition) of the16S rRNA gene. It was determined through the sequence alignment, and the symmetry was 90% with the Italian isolate of Pantoea species LL92 (ID: KF202812.1). These variations in the Pantoea local Iraqi isolate were registered in NCBI (ID: OM971851). This bacterial genus recently descended from the species of Enterobacter sp. The isolation of Pantoea sp. was from UTIs, while previously, in most studies, they were isolated from the surrounding environment. [ABSTRACT FROM AUTHOR]

Madura cattle breeders in rural Indonesia prefer to request artificial insemination services for their cows with Limousin bull's freezethawed semen. However, crossbred Madura-Limousin (Madrasin) bulls reported a high infertility rate. The cytochrome b (Cytb) of mitochondrial DNA (mtDNA) have been linked to certain types of male infertility. This study aimed to identify the mutation Cytb mtDNA in Madura-Limousin crossbred cattle to develop a fundamental breeding approach that would promote animal protein production and preserve the genetics of purebred Madura cattle. Blood samples were collected from the two bulls of crossbred Madura-Limousin, purebred Madura, and Limousin bulls for DNA analysis. The polymerase chain reaction was used to amplify the Cytb mtDNA, which was then sequenced using the Sanger method. The MEGA 7.0 software was used with the neighbor-joining method to construct the phylogenetic tree. Compared to the purebred Madura cattle (n= 2) and purebred Limousin bulls (n= 2), the crossbred Madura-Limousin bulls (also known as Madrasin) (n= 3) exhibited alterations in their nucleotide sequence of 13 nucleotide mutation between Madura compared to madrasin, and 14 nucleotide mutation between Limousin compared to Madrasin cattle. As observed in the resulting clades, the purebred Madura and Limousin cattle were grouped, while Madrasin crossbred cattle were separated. It could be concluded that Madrasin bulls exhibited alterations in their nucleotide and protein sequences of Cytb mtDNA, placing them in a distinct group from purebred Madura cattle and Limousin bulls. [ABSTRACT FROM AUTHOR]

Current DNA base editors contain nuclease and DNA deaminase that enables deamination of cytosine (C) or adenine (A), but no method for guanine (G) or thymine (T) editing is available at present. Here we developed a deaminase-free glycosylase-based guanine base editor (gGBE) with G editing ability, by fusing Cas9 nickase with engineered N-methylpurine DNA glycosylase protein (MPG). By several rounds of MPG mutagenesis via unbiased and rational screening using an intron-split EGFP reporter, we demonstrated that gGBE with engineered MPG could increase G editing efficiency by more than 1500 fold. Furthermore, this gGBE exhibited high base editing efficiency (up to 81.2%) and high G-to-T or G-to-C (i.e. G-to-Y) conversion ratio (up to 0.95) in both cultured human cells and mouse embryos. Thus, we have provided a proof-of-concept of a new base editing approach by endowing the engineered DNA glycosylase the capability to selectively excise a new type of substrate. [ABSTRACT FROM AUTHOR]

To investigate the role of oxidative stress-induced DNA damage and mutagenesis in cellular senescence and immortalization, here we profiled spontaneous and methylene blue plus light-induced mutations in the cII gene from λ phage in transgenic mouse embryonic fibroblasts during the transition from primary culture through senescence and immortalization. Consistent with detection of characteristic oxidized guanine lesions (8-oxodG) in the treated cells, we observed significantly increased relative cII mutant frequency in the treated pre-senescent cells which was augmented in their immortalized counterparts. The predominant mutation type in the treated pre-senescent cells was G:C→T:A transversion, whose frequency was intensified in the treated immortalized cells. Conversely, the prevailing mutation type in the treated immortalized cells was A:T→C:G transversion, with a unique sequence-context specificity, i.e. flanking purines at the 5' end of the mutated nucleotide. This mutation type was also enriched in the treated pre-senescent cells, although to a lower extent. The signature mutation of G:C→T:A transversions in the treated cells accorded with the well-established translesion synthesis bypass caused by 8-oxodG, and the hallmark A:T→C:G transversions conformed to the known replication errors because of oxidized guanine nucleosides (8-OHdGTPs). The distinctive features of photosensitization-induced mutagenesis in the immortalized cells, which were present at attenuated levels, in spontaneously immortalized cells provide insights into the role of oxidative stress in senescence bypass and immortalization. Our results have important implications for cancer biology because oxidized purines in the nucleoside pool can significantly contribute to genetic instability in DNA mismatch repair-defective human tumors.

Abstract Background KRAS-mutated non-small cell lung cancer (NSCLC) accounts for 23–35% and 13–20% of all NSCLCs in white patients and East Asians, respectively, and is therefore regarded as a major therapeutic target. However, its epidemiology and clinical characteristics have not been fully elucidated because of its wide variety of mutational subtypes. Here, we focused on two distinct base substitution types: transversion mutations and transition mutations, as well as their association with environmental factors and clinical outcome. Methods Dataset from the Japan Molecular Epidemiology Study, which is a prospective, multicenter, and molecular study epidemiology cohort study involving 957 NSCLC patients who underwent surgery, was used for this study. Questionnaire-based detailed information on clinical background and lifestyles was also used to assess their association with mutational subtypes. Somatic mutations in 72 cancer-related genes were analyzed by next-generation sequencing, and KRAS mutations were classified into three categories: transversions (G > C or G > T; G12A, G12C, G12R, G12V), transitions (G > A; G12D, G12S, G13D), and wild-type (WT). Clinical correlations between these subtypes have been investigated, and recurrence-free survival (RFS) and overall survival (OS) were evaluated. Results Of the 957 patients, KRAS mutations were detected in 80 (8.4%). Of these, 61 were transversions and 19 were transitions mutations. Both pack-years of smoking and smoking duration had significant positive correlation with the occurrence of transversion mutations (p = 0.03 and

Background: KRAS-mutated non-small cell lung cancer (NSCLC) accounts for 23-35% and 13-20% of all NSCLCs in white patients and East Asians, respectively, and is therefore regarded as a major therapeutic target. However, its epidemiology and clinical characteristics have not been fully elucidated because of its wide variety of mutational subtypes. Here, we focused on two distinct base substitution types: transversion mutations and transition mutations, as well as their association with environmental factors and clinical outcome.Methods: Dataset from the Japan Molecular Epidemiology Study, which is a prospective, multicenter, and molecular study epidemiology cohort study involving 957 NSCLC patients who underwent surgery, was used for this study. Questionnaire-based detailed information on clinical background and lifestyles was also used to assess their association with mutational subtypes. Somatic mutations in 72 cancer-related genes were analyzed by next-generation sequencing, and KRAS mutations were classified into three categories: transversions (G > C or G > T; G12A, G12C, G12R, G12V), transitions (G > A; G12D, G12S, G13D), and wild-type (WT). Clinical correlations between these subtypes have been investigated, and recurrence-free survival (RFS) and overall survival (OS) were evaluated.Results: Of the 957 patients, KRAS mutations were detected in 80 (8.4%). Of these, 61 were transversions and 19 were transitions mutations. Both pack-years of smoking and smoking duration had significant positive correlation with the occurrence of transversion mutations (p = 0.03 and < 0.01, respectively). Notably, transitions showed an inverse correlation with vegetable intake (p = 0.01). Patients with KRAS transitions had the shortest RFS and OS compared to KRAS transversions and WT. Multivariate analysis revealed that KRAS transitions, along with age and stage, were significant predictors of shorter RFS and OS (HR 2.15, p = 0.01; and HR 2.84, p < 0.01, respectively).Conclusions: Smoking exposure positively correlated with transversions occurrence in a dose-dependent manner. However, vegetable intake negatively correlated with transitions. Overall, KRAS transition mutations are significantly poor prognostic factors among resected NSCLC patients. [ABSTRACT FROM AUTHOR]

The results of studying the variability of sequences of the ITS rDNA region for 17 species of the genus Spiraea (Magnoliópsida: Rosaceae) occurring within the Russian part of the ranges and in adjacent territories are presented. The results demonstrate the presence of single-nucleotide substitutions (transitions and transversions) and deletions/insertions, including those specific at the level of subgenera, sections, cycles, and series. The variability in the ITS1 intergenic spacer is higher than in ITS2. The high importance of ITS as a molecular marker in the resolution of phylogenetic relationships in the genus Spiraea is emphasized. Closely related Spiraea species usually differ in ITS sequences, but the polymorphic section Chamaedryon has the greatest difficulties in identifying taxa. Phylogenetic analysis carried out in various ways (ML, MP, and BI) confirms the monophyletic origin of the genus Spiraea and the ancient sections Spiraea and Calospira. A hypothesis is formulated about the paraphyletic nature of the section Chamaedryon, which more evolutionarily young, diverse, and richest in the number of species. It is assumed that the paraphyly of the Chamaedryon section is associated with divergence of traits and subsequent isolation of species along with multiple migrations under the influence of contrasting environmental conditions. [ABSTRACT FROM AUTHOR]

Key message: We analyzed the blackberry SNP-unigene functions and pathways and mined specific SNP loci related to flavonoid and anthocyanin synthesis during fruit maturation at the molecular level. Blackberry fruit is rich in nutrients and has medicinal functions. Molecular-assisted breeding can accelerate the production of blackberry cultivars with high anthocyanin content. Single nucleotide polymorphisms (SNPs) have become important molecular markers in plant research. Thus, we sequenced the transcriptome of unripe and ripe blackberry fruits to obtain information on SNP loci and their function. In this study, a total of 730,589 SNP loci distributed in 41,408 unigenes were identified. No codon preference was found when the codon position of an SNP locus was considered. The proportion of transition-type SNPs was 61.01%, which was significantly higher than that of transversion-type SNPs (38.99%). A total of 436 differentially expressed transcription factors (TFs) were found to contain SNP loci; these TFs could be divided into 47 families. The results of KEGG metabolic pathway analysis and GO classification were related to metabolism. Moreover, we identified 35, 2 and 2 SNP-differentially expressed unigenes (DEGs) associated with flavonoid synthesis, flavone and flavonol biosynthesis, and anthocyanin synthesis, respectively. These results lay a foundation for the development of SNP molecular markers for blackberry breeding and provide the possibility of accelerating genetic improvement to obtain blackberries with high contents of secondary metabolites such as flavonoids and anthocyanins. [ABSTRACT FROM AUTHOR]

A common approach to estimate the strength and direction of selection acting on protein coding sequences is to calculate the dN/dS ratio. The method to calculate dN/dS has been widely used by many researchers and many critical reviews have been made on its application after the proposition by Nei and Gojobori in 1986. However, the method is still evolving considering the non-uniform substitution rates and pretermination codons. In our study of SNPs in 586 genes across 156 Escherichia coli strains, synonymous polymorphism in 2-fold degenerate codons were higher in comparison to that in 4-fold degenerate codons, which could be attributed to the difference between transition (Ti) and transversion (Tv) substitution rates where the average rate of a transition is four times more than that of a transversion in general. We considered both the Ti/Tv ratio, and nonsense mutation in pretermination codons, to improve estimates of synonymous (S) and non-synonymous (NS) sites. The accuracy of estimating dN/dS has been improved by considering the Ti/Tv ratio and nonsense substitutions in pretermination codons. We showed that applying the modified approach based on Ti/Tv ratio and pretermination codons results in higher values of dN/dS in 29 common genes of equal reading-frames between E. coli and Salmonella enterica. This study emphasizes the robustness of amino acid composition with varying codon degeneracy, as well as the pretermination codons when calculating dN/dS values. [ABSTRACT FROM AUTHOR]

BACKGROUND: Digitaria sanguinalis has been identified as a species at high risk of evolving herbicide resistance, but thus far, there are no records of resistance to glyphosate. This weed is one of the most common weeds of summer crops in extensive cropping areas in Argentina. It shows an extended period of seedling emergence with several overlapping cohorts during spring and summer, and is commonly controlled with glyphosate. However, a D. sanguinalis population was implicated as a putative glyphosate‐resistant biotype based on poor control at recommended glyphosate doses. RESULTS: The field‐collected D. sanguinalis population (Dgs R) from the Rolling Pampas has evolved glyphosate resistance. Differences in plant survival and shikimate levels after field‐recommended and higher glyphosate doses were evident between Dgs R and the known susceptible (Dgs S) population; the resistance index was 5.1. No evidence of differential glyphosate absorption, translocation, metabolism or basal EPSPS activity was found between Dgs S and Dgs R populations; however, a novel EPSPS Pro‐106‐His point substitution is probably the primary glyphosate resistance‐endowing mechanism. EPSPS in vitro enzymatic activity demonstrated that an 80‐fold higher concentration of glyphosate is required in Dgs R to achieve similar EPSPS activity inhibition to that in the Dgs S population. CONCLUSION: This study reports the first global case of glyphosate resistance in D. sanguinalis. This unlikely yet novel transversion at the second position of the EPSPS 106 codon demonstrates the intensity of glyphosate pressure in selecting unexpected glyphosate resistance alleles if they retain EPSPS functionality. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Feather colours are used by avian species for defense, adaptation and signaling. Melanocortin-1 receptor (MC1R) gene is one of the genes responsible for feather colour. This study identified selection signatures in MC1R gene of Nigerian indigenous turkeys (NIT) using British United turkeys (BUT) as control breed to investigate the evolutionary processes that have shaped NIT with various feather colours. Complete MC1R gene of 146 NIT (76 males and 70 females) and 32 BUT (18 males and 14 females) were sequenced. Transition/transversion and codon usage biases were predicted using MEGA v6 software. The selective force acting on the gene was predicted using HyPhy software. The FST values were estimated using Arlequin v3.5. The highest transition/transversion bias was predicted for white BUT (1.00) while the lowest was predicted for black NIT (0.50). Negative dN-dS values, indicative of purifying selection, were observed in MC1R gene of all the turkeys. The highest pairwise FST was observed between the MC1R gene of white BUT and black NIT while the least was observed between lavender NIT and white NIT. No recombination event was observed in black NIT and white BUT. The relative synonymous codon usage was the same among different colours for some codons. Presence of purifying selection in MC1R gene of all the turkeys with different feather colours confirms that the gene plays role in many biological processes such as feather colouration, behaviour, pain perception, immunity, growth and adaptation. The results also suggested that the genetic mechanisms generating different feather colours in turkeys are conserved. [ABSTRACT FROM AUTHOR]

Transversion and transition mutations have variable effects on the stability of RNA secondary structure considering that the former destabilizes the double helix geometry to a greater extent by introducing purine:purine (R:R) or pyrimidine:pyrimidine (Y:Y) base pairs. Therefore, transversion frequency is likely to be lower than that of transition in the secondary structure regions of RNA genes. Here, we performed an analysis of transition and transversion frequencies in tRNA genes defined well with secondary structure and compared with the intergenic regions in five bacterial species namely Escherichia coli, Klebsiella pneumoniae, Salmonella enterica, Staphylococcus aureus and Streptococcus pneumoniae using a large genome sequence data set. In general, the transversion frequency was observed to be lower than that of transition in both tRNA genes and intergenic regions. The transition to transversion ratio was observed to be greater in tRNA genes than that in the intergenic regions in all the five bacteria that we studied. Interestingly, the intraspecies base substitution analysis in tRNA genes revealed that non-compensatory substitutions were more frequent than compensatory substitutions in the stem region. Further, transition to transversion ratio in the loop region was observed to be significantly lesser than that among the non-compensatory substitutions in the stem region. This indicated that the transversion is more deleterious than transition in the stem regions. In addition, substitutions from amino bases (A/C) to keto bases (G/T) were also observed to be more than the reverse substitutions in the stem region. Substitution from amino bases to keto bases are likely to facilitate the stable G:U pairing unlike the reverse substitution that facilitates the unstable A:C pairing in the stem region of tRNA. This work provides additional support that the secondary structure of tRNA molecule is what drives the different substitutions in its gene sequence. [ABSTRACT FROM AUTHOR]

Studying and understanding the changes in the molecular sequences of plants are important to better identification and classifying the species. Internal transcribed spacer (ITS) regions are consider an informative genetic sequence to find out the variation among species of the same genus. In this study, ITS regions of Haplophyllum collected in Ashdagh Mountain were amplified, analyzed, and compared with reference species gathered from gene bank. The results showed that the collected species was closely related to Haplophyllum blanchei and Haplophyllum tuberculatum. In addition, there were differences in the number of the base pairs in the ITS1 region between Haplophyllum sp. and H. blanchei and H. tuberculatum. The transition to transversion ratio between Haplophyllum sp. and H. tuberculatum was lower (=1) than with other species. The results reveals that the studied plant is could be a new species in Iraq. To the best of our knowledge, this study is the first molecular taxonomic study done to identify Haplophyllum species in Ashdagh mountain in Sangaw/Suleimani. [ABSTRACT FROM AUTHOR]

This study used codon analysis (dN/dS and Tv/Ti) to investigate selection pressure and genetic structure in the highly polymorphic Psammobates tentorius species complex, and amino acid sequences to construct a phylogeny tree for it. Our results revealed a strong selection signal at node 'C2 + C3', possibly driven by aridity intensification resulting from the development of the Benguela Current. A similar signal was noticed at C3, possibly due to the same driving force. These findings suggest that environmental selection pressure favoured those groups and that further cladogenic events were possible. Selection pressure was also found to be high at C1, C4 and C7, which may indicate that they are also favoured by the current selection pressure. The codon‐based phylogeny did not retrieve any potentially undescribed species, but nonetheless provided support for the validity of the seven distinct clades retrieved with the DNA sequence data. The amino acid sequence‐based phylogeny generally supported the seven lineages as valid putative species. Investigation at the genomic scale could, however, help to solve the issue. In general, we found the codon, dN, dS, Tv, Ti and amino acid sequence‐based phylogenetic inferences useful in species delimitation and recommend their use in species delimitation studies. [ABSTRACT FROM AUTHOR]

Abstract Background Chloroplasts are one of the most indispensable organelles that make life forms on the earth possible by their capacity to photosynthesize. These organelles possess a circular genome with a number of coding genes responsible for self-regulation. tRNAs are an important evolutionary-conserved gene family that are responsible for protein translation. However, within the chloroplast genome, tRNA machinery are poorly understood. Results In the present study, the chloroplast genome of six monocot plants, Oryza nivara (NC_005973), Oryza sativa (NC_001320), Sachharum officinarum (NC_006084), Sorghum bicolor (NC_008602), Triticum aestivum (NC_002762), and Zea mays (NC_001666) were downloaded and analyzed to identify tRNA sequences. Further analysis of the tRNA sequences in the chloroplast genomes of the monocot plants resulted in the identification of several novel features. The length of tRNAs in the chloroplast genome of the monocot plants ranged from 59 to 155 nucleotides. Pair-wise sequence alignment revealed the presence of a conserved A-C-x-U-A-x-U-A-x-U-x5-U-A-A nucleotide consensus sequence. In addition, the tRNAs in chloroplast genomes of the monocot plants also contain 21–28 anti-codons against 61 sense codons in the genome. They also contain a group I intron and a C-A-U anti-codon for tRNAIle, which is a common anti-codon of tRNAMet. Evolutionary analysis indicates that tRNAs in the chloroplast genome have evolved from multiple common ancestors, and tRNAMet appears to be the ancestral tRNA that underwent duplication and diversification to give rise to other tRNAs. Conclusion The results obtained from the study of chloroplast tRNA will greatly help to increase our understanding of tRNA biology at a new level. Functional studies of the reported novel aspects of the chloroplast tRNA of the monocot plants will greatly help to decipher their roles in diverse cellular processes.

Cet article porte sur l’habiter posthumain représenté dans les jeux vidéo cyberpunk de la franchise WATCH_DOGS. Après une redéfinition du posthumain en termes ontogéographiques, les spécificités de l’habiter posthumain seront décrites en tant que transversion, phénomène entendu comme le fruit d’un mouvement dynamique allant de l’inversion (introjection du milieu humain dans les limites physiques du corps par le biais de la technique) à l’éversion (projection du corps dans le milieu par le biais de la technique). S’ensuivra une analyse portant sur la manière dont WATCH_DOGS traite de la transversion dans le cadre de la ville intelligente vue comme une ville posthumaine.

To understand the phylogenetic status of Ariidae, Bagridae and Plotosidae catfishes, this study was planned using the barcode gene, cytochrome oxidase I (COI). Totally 71 species were used in phylogenetic reconstructions under maximum parsimony, maximum likelihood and Bayesian inference criteria. The one-way ANOVA showed that the three catfish families are significantly different (F= 19.79, d.f. = 3; 116, P< 0.0001 (Plotosidae); F= 44.21, d.f.= 3; 986, P< 0.0001 (Ariidae); F= 24.83, d.f.= 3; 1322, P< 0.0001 (Bagridae). In MP, ML and BI based phylogenetic tree of Ariidae, Plicofollis genus displayed as a monophyletic group with higher bootstrap and posterior probability values for all the species except two species of Neoarius, which intervened separating P. polystaphylodon. In the phylogenetic tree of Plotoside, Plotosus genus displayed as monophyletic group with higher bootstrap and posterior probability values for all the eight species. In the case of Bagridae phylogeentic tree, Mystus genus displayed as a monophyletic group with higher bootstrap and posterior probability values for all the species except Mystus montanus forming a distant and distinct clade whereas Mystus tengara collides into monophyletic clade when Neotropius genuswas removed. By this study we could establish a phylogenetic hypothesis for all the 36 catfish families and examine the monophyly status of the subfamilies and genera.

To understand SARS-CoV-2 microevolution, this study explored the genome-wide frequency, gene-wise distribution, and molecular nature of all point-mutations detected across its 71,703 RNA-genomes deposited in GISAID till 21 August 2020. Globally, nsp1 / nsp2 and orf7a / orf3a were the most mutation-ridden non-structural and structural genes respectively. Phylogeny of 4618 spatiotemporally-representative genomes revealed that entities belonging to the early lineages are mostly spread over Asian countries, including India, whereas the recently-derived lineages are more globally distributed. Of the total 20,163 instances of polymorphism detected across global genomes, 12,594 and 7569 involved transitions and transversions, predominated by cytidine-to-uridine and guanosine-to-uridine conversions, respectively. Positive selection of nonsynonymous mutations (dN/dS >1) in most of the structural, but not the non-structural, genes indicated that SARS-CoV-2 has already harmonized its replication/transcription machineries with the host metabolism, while it is still redefining virulence/transmissibility strategies at the molecular level. Mechanistic bases and evolutionary/pathogenicity-related implications are discussed for the predominant mutation-types. • SARS-CoV-2 microevolution was studied in 71,703 whole-genomes sequenced worldwide until 21.08.2020. • Globally, nsp1 / nsp2 and orf7a / orf3a were the most mutation-ridden non-structural and structural genes respectively. • Whole-genome phylogeny revealed that entities belonging to the early lineages are mostly spread over Asian countries. • A transition:transversion ratio of 2.66 characterized SARS-CoV-2, with C→U and G→U being the predominant mutation-types. • Missense mutations are positively selected mostly in structural genes; missense C→Us tend to usher hydrophobic amino acids. [ABSTRACT FROM AUTHOR]

To understand the phylogenetic status of Ariidae, Bagridae and Plotosidae catfishes, this study was planned using the barcode gene, cytochrome oxidase I (COI). Totally 71 species were used in phylogenetic reconstructions under maximum parsimony, maximum likelihood and Bayesian inference criteria. The oneway ANOVA showed that the three catfish families are significantly different (F = 19.79, d.f. = 3; 116, P< 0.0001 (Plotosidae); F = 44.21, d.f. = 3; 986, P< 0.0001 (Ariidae); F = 24.83, d.f. = 3; 1322, P< 0.0001 (Bagridae). In MP, ML and BI based phylogenetic tree of Ariidae, Plicofollis genus displayed as a monophyletic group with higher bootstrap and posterior probability values for all the species except two species of Neoarius, which intervened separating P. polystaphylodon. In the phylogenetic tree of Plotoside, Plotosus genus displayed as monophyletic group with higher bootstrap and posterior probability values for all the eight species. In the case of Bagridae phylogeentic tree, Mystus genus displayed as a monophyletic group with higher bootstrap and posterior probability values for all the species except Mystus montanus forming a distant and distinct clade whereas Mystus tengara collides into monophyletic clade when Neotropius genuswas removed. By this study we could establish a phylogenetic hypothesis for all the 36 catfish families and examine the monophyly status of the subfamilies and genera. [ABSTRACT FROM AUTHOR]

Bacteria that resist a broad spectrum of antibiotics are known as nosocomial bacteria. Moreover, nosocomial infections cause serious problems all around the world. The aim of this study is to detect phylogenetic tree of some nosocomial bacteria isolated from Ramadi Teaching Hospital. In this study, sixty five samples were taken from different locations of the Ramadi Teaching hospital and were cultured on different media. They were also stained and examined under microscopy. It was found that there are 40 bacterial isolates and 25 fungal isolates after cultured on different media. Pure colonies were obtained after re-culture for bacterial isolates and then extracted the DNA from the 04 isolated samples and measuring its concentration. Using the specific primer for 16SrRNA genes, the samples were amplified by a PCR. All the isolated were sent to work the sequences and know the bacterial genus, as it appeared that there is a variation between the genera for different locations and also it was found that there is a variation from the comparison with the global strains of the NCBI and this indicates an evolution in some of the isolated strains and their resistance. It is important to mention that all samples isolated from the intensive care unit (ICUs), neonates, laboratories, emergency and kitchen contain variations in the sequences compared with NCBI. [ABSTRACT FROM AUTHOR]

The aim of this study is to diagnose bacterial strains in hospitals by the 16SrRNA gene and to know the variation of the nucleotide sequence. The study of bacteria in hospitals is of great importance to identify the extent of change in these species and their resistance to antibiotics. This indicates that these bacteria have the ability to change or obtain new variants to be able to resist antibiotics. In this study, samples were taken from different locations of the Ramadi Teaching hospital for women and children and were cultured on different media. They were also stained and examined under light microscopy and some biochemical tests were conducted. Pure colonies were obtained after re-culture and then extracted the DNA from the 16 isolated samples and measuring its concentration. Using the specific primer for 16SrRNA genes, the samples were amplified by a PCR and the size was shown to be 1500 bp. The unknown bacteria were sent to the sequence. Some samples showed variations in comparison with the data presented by NCBI. This is evidence of some variations shown by bacteria to overcome antibiotics and increase their severity and spread in hospitals, whether in kitchens, emergency or preterm infants, as well as laboratory staff and lab equipment. [ABSTRACT FROM AUTHOR]

Discovering new genetic mutations is vital for expanding genetic resources for exploring the functions and breeding applications of genes. In this study, we created new mutant populations of rice and evaluated its effectiveness by using a chemical mutagen diepoxybutane (DEB) with the expectation of manageably causing small-scale deletions that induce knock-out mutations. Compared with the more common mutagen, ethyl methanesulfonate (EMS), DEB exhibited approximately 160 times the adverse impact on the early growth of rice. At 0.3 mM, which was 1/160 the concentration of EMS in the control population, the heading date in the DEB-mutated population showed dispersion, albeit with a small standard deviation. Therefore, similar to EMS, DEB has been shown to induce DNA mutations. According to the screening of waxy mutants using the Targeting Induced Local Lesions in Genomes (TILLING) method, DEB-mutated populations had nearly similar mutation frequencies to those of EMS-mutated populations. Therefore, we successfully isolated five mutant lines from the DEB-mutated population. Some of these mutants exhibited a low-amylose phenotype, which is applicable to breeding leading to enhanced taste evaluation. To utilize these mutated alleles, we developed co-dominant DNA markers. In this study, EMS induced transition mutations, as previously reported. In contrast, DEB specifically induced transversion mutations rather than small-scale deletions contrary to our initial expectations. These results demonstrate that DEB has a novel point of action for mutation and is useful for expanding genetic resources for crops. [ABSTRACT FROM AUTHOR]

Heat shock protein (HSP) 90 gene provides protection and adaptation to thermal assault and certain polymorphisms have been associated to heat tolerance in humans and animals. Single nucleotide polymorphisms (SNPs) of HSP 90 gene were used to evaluate the scientific basis of heat tolerance in four zebu breeds of Nigeria. The DNA was extracted from skin tissue of 90 adult bulls representing White Fulani (WF), Sokoto Gudali (SG), Red Bororo (RB), and Ambala (AM). The SNPs were determined in DNAs using PCR, sequencing, and visualization and bio-editing by chromatogram in SeqMan Ngen tool. Subsequently, respective genotypes were constructed and genotypic and allelic frequencies were computed. Also, body parameters related to heat stress (HS) including body temperature (BT), rectal temperature (RT), and respiratory rates (RR) were taken for each animal before biological sampling and heat tolerance coefficient (HTC) was calculated. We detected four SNPs distinct/specific for each breed as follows: change from thymine (T) to guanine (G) at position 116 (T116G) in RB, G to cytosine (C) at 220 (G220C) in SG, G to adenine (A) at two positions, 346 (G346A) and 390 (G390A) in AM and WF, respectively. Heterozygous SNPs showed significantly lower values (P < 0.0001) for BT, RT, RR, and HTC than homozygous genotypes at all positions. We hypothesize that animals with heterozygous SNPs in exon 3 of HSP 90 may be tolerant to HS. These SNPs can be used as bio-markers for screening large populations of cattle for tolerance to hot tropical conditions in Nigeria and other sub-humid places. [ABSTRACT FROM AUTHOR]

We report an isolated sulfite oxidase deficiency in the first child boy of a non-consanguineous Caucasian family. He's a compound heterozygote for the sulfite oxidase gene, presenting low cystine, undetectable homocysteine and normal uric acid blood concentrations and undetectable sulfite oxidase activity in his cultured fibroblasts. Both mutations are not reported yet. The clinical presentation was typical and severe, with generalized status epilepticus and premature death.

Semidwarfism is an important agronomic trait in rice breeding programs. The semidwarf mutant gene Sdt97 was previously described. However, the molecular mechanism underlying the mutant is yet to be elucidated. In this study, we identified the mutant gene by a map-based cloning method. Using a residual heterozygous line (RHL) population, Sdt97 was mapped to the long arm of chromosome 6 in the interval of nearly 60 kb between STS marker N6 and SNP marker N16 within the PAC clone P0453H04. Sequencing of the candidate genes in the target region revealed that a base transversion from G to C occurred in the 5′ untranslated region of Sdt97. qRT-PCR results confirmed that the transversion induced an obvious change in the expression pattern of Sdt97 at different growth and developmental stages. Plants transgenic for Sdt97 resulted in the restoration of semidwarfism of the mutant phenotype, or displayed a greater dwarf phenotype than the mutant. Our results indicate that a point mutation in the 5′ untranslated region of Sdt97 confers semidwarfism in rice. Functional analysis of Sdt97 will open a new field of study for rice semidwarfism, and also expand our knowledge of the molecular mechanism of semidwarfism in rice.

Transfer RNA (tRNA) plays a central role in protein synthesis and acts as an adaptor molecule between an mRNA and an amino acid. A tRNA has an L-shaped clover leaf-like structure and contains an acceptor arm, D-arm, D-loop, anti-codon arm, anti-codon loop, variable loop, Ψ-arm and Ψ-loop. All of these arms and loops are important in protein translation. Here, we aimed to delineate the genomic architecture of these arms and loops in cyanobacterial tRNA. Studies from tRNA sequences from 61 cyanobacterial species showed that, except for few tRNAs (tRNAAsn, tRNALeu, tRNAGln, and tRNAMet), all contained a G nucleotide at the 1st position in the acceptor arm. tRNALeu and tRNAMet did not contain any conserved nucleotides at the 1st position whereas tRNAAsn and tRNAGln contained a conserved U1 nucleotide. In several tRNA families, the variable region also contained conserved nucleotides. Except for tRNAMet and tRNAGlu, all other tRNAs contained a conserved A nucleotide at the 1st position in the D-loop. The Ψ-loop contained a conserved U1-U2-C3-x-A5-x-U7 sequence, except for tRNAGly, tRNAAla, tRNAVal, tRNAPhe, tRNAThr, and tRNAGln in which the U7 nucleotide was not conserved. However, in tRNAAsp, the U7 nucleotide was substituted with a C7 nucleotide. Additionally, tRNAArg, tRNAGly, and tRNALys of cyanobacteria contained a group I intron within the anti-codon loop region. Maximum composite likelihood study on the transition/transversion of cyanobacterial tRNA revealed that the rate of transition was higher than the rate of transversion. An evolutionary tree was constructed to understand the evolution of cyanobacterial tRNA and analyses revealed that cyanobacterial tRNA may have evolved polyphyletically with high rate of gene loss.

Next-generation sequencing (NGS) technologies have revolutionized cancer genomics due to their high throughput sequencing capacity. Reports of the gene mutation profiles of various cancers by many researchers, including international cancer genome research consortia, have increased over recent years. In addition to detecting somatic mutations in tumor cells, NGS technologies enable us to approach the subject of carcinogenic mechanisms from new perspectives. Deep sequencing, a method of optimizing the high throughput capacity of NGS technologies, allows for the detection of genetic aberrations in small subsets of premalignant and/or tumor cells in noncancerous chronically inflamed tissues. Genome-wide NGS data also make it possible to clarify the mutational signatures of each cancer tissue by identifying the precise pattern of nucleotide alterations in the cancer genome, providing new information regarding the mechanisms of tumorigenesis. In this review, we highlight these new methods taking advantage of NGS technologies, and discuss our current understanding of carcinogenic mechanisms elucidated from such approaches.

Aim To determine the capacity of next-generation sequencing (NGS) for quantifying edited and unedited HDV populations, and to confirm if edition is a general phenomenon taking place along the entire HDV region analyzed, as we previously reported (Homs M et al. PLoS One 2016, 11, e0158557). Methods Four serum samples from 4 patients with chronic HDV/HBV infection were included in the study. The region selected for analysis covered 360 nucleotides (nt), positions 910–1270 of the HDV genome, which included the HDAg ORF editing site (nt 1014 within codon 196). Quantification of edited and unedited genomes was performed by molecular cloning and Sanger sequencing and by NGS. To evaluate the reliability of the NGS values obtained, we combined a clone with an edited codon and one with an unedited codon in known percentages in a series of artificial mixtures, which were then analyzed by NGS. In addition, we determined the nt changes occurring over the complete amplified region after excluding the editing codon (196) to evaluate edition along it. Results In total, 11,208 quality-filtered sequences were obtained in the 4 samples. The 95% confidence intervals for the proportions of unedited populations by molecular cloning and NGS were overlapping, and those of cloning were wider, indicating that they are comparable and that NGS is more precise than cloning. Unedited genomes predominated over edited ones in all 4 samples analyzed by NGS and in 3 of the 4 samples analyzed by molecular cloning. In total, 83,276 quality-filtered sequences were obtained from the artificial mixtures. Percentages of the two viral populations detected by NGS in these mixtures were comparable to the expected percentages. Evaluation of edition along the HDV coding region showed that transitions were more frequent than transversions, accounting for 63.09% and 36.91%, respectively. Interestingly, among the 4 possible transition-type changes, G:A and A:G accounted for 73.86% of the total. Conclusion Next-generation sequencing proved useful to quantify edited and unedited HDV genomes, and provided relevant information on the HDV quasispecies. [ABSTRACT FROM AUTHOR]

Transfer RNA (tRNA) plays a central role in protein synthesis and acts as an adaptor molecule between an mRNA and an amino acid. A tRNA has an L-shaped clover leaf-like structure and contains an acceptor arm, D-arm, D-loop, anti-codon arm, anti-codon loop, variable loop, Ψ-arm and Ψ-loop. All of these arms and loops are important in protein translation. Here, we aimed to delineate the genomic architecture of these arms and loops in cyanobacterial tRNA. Studies from tRNA sequences from 61 cyanobacterial species showed that, except for few tRNAs (tRNAAsn, tRNALeu, tRNAGln, and tRNAMet), all contained a G nucleotide at the 1st position in the acceptor arm. tRNALeu and tRNAMet did not contain any conserved nucleotides at the 1st position whereas tRNAAsn and tRNAGln contained a conserved U1 nucleotide. In several tRNA families, the variable region also contained conserved nucleotides. Except for tRNAMet and tRNAGlu, all other tRNAs contained a conserved A nucleotide at the 1st position in the D-loop. The Ψ-loop contained a conserved U¹-U²-C³-x-A5-x-U7 sequence, except for tRNAGly, tRNAAla, tRNAVal, tRNAPhe, tRNAThr, and tRNAGln in which the U7 nucleotide was not conserved. However, in tRNAAsp, the U7 nucleotide was substituted with a C7 nucleotide. Additionally, tRNAArg, tRNAGly, and tRNALys of cyanobacteria contained a group I intron within the anti-codon loop region. Maximum composite likelihood study on the transition/transversion of cyanobacterial tRNA revealed that the rate of transition was higher than the rate of transversion. An evolutionary tree was constructed to understand the evolution of cyanobacterial tRNA and analyses revealed that cyanobacterial tRNA may have evolved polyphyletically with high rate of gene loss. [ABSTRACT FROM AUTHOR]

The substitution rates of transitions are higher than expected by chance relative to those of transversions. Many have argued that selection disfavors transversions, as nonsynonymous transversions are less likely to conserve biochemical properties of the original amino acid. Only recently has it become feasible to directly test this selective hypothesis by comparing the fitness effects of a large number of transition and transversion mutations. For example, a recent study of six viruses and one beta-lactamase gene did not find evidence supporting the selective hypothesis. Here, we analyze the relative fitness effects of transition and transversion mutations from our recently published genome-wide study of mutational fitness effects in influenza virus. In contrast to prior work, we find that transversions are significantly more detrimental than transitions. Using what we believe to be an improved statistical framework, we also identify a similar trend in two HIV data sets. We further demonstrate a fitness difference in transition and transversion mutations using four deep mutational scanning data sets of influenza virus and HIV, which provided adequate statistical power. We find that three of the most commonly cited radical/conservative amino acid categories are predictive of fitness, supporting their utility in studies of positive selection and codon usage bias. We conclude that selection is a major contributor to the transition: transversion substitution bias in viruses and that this effect is only partially explained by the greater likelihood of transversion mutations to cause radical as opposed to conservative amino acid changes. [ABSTRACT FROM AUTHOR]

The DNA barcodes are generally interpreted using distance-based and character-based methods. The former uses clustering of comparable groups, based on the relative genetic distance, while the latter is based on the presence or absence of discrete nucleotide substitutions. The distance-based approach has a limitation in defining a universal species boundary across the taxa as the rate of mt DNA evolution is not constant throughout the taxa. However, character-based approach more accurately defines this using a unique set of nucleotide characters. The character-based analysis of full-length barcode has some inherent limitations, like sequencing of the full-length barcode, use of a sparse-data matrix and lack of a uniform diagnostic position for each group. A short continuous stretch of a fragment can be used to resolve the limitations. Here, we observe that a 154-bp fragment, from the transversion-rich domain of 1367 COI barcode sequences can successfully delimit species in the three most diverse orders of freshwater fishes. This fragment is used to design species-specific barcode motifs for 109 species by the character-based method, which successfully identifies the correct species using a pattern-matching program. The motifs also correctly identify geographically isolated population of the Cypriniformes species. Further, this region is validated as a species-specific mini-barcode for freshwater fishes by successful PCR amplification and sequencing of the motif (154 bp) using the designed primers. We anticipate that use of such motifs will enhance the diagnostic power of DNA barcode, and the mini-barcode approach will greatly benefit the field-based system of rapid species identification. [ABSTRACT FROM AUTHOR]