Strong inclination toward transition mutation in nucleotide substitutions by poliovirus replicase

1989 ◽  
Vol 207 (1) ◽  
pp. 175-182 ◽  
Author(s):  
Shusuke Kuge ◽  
Noriyuki Kawamura ◽  
Akio Nomoto
Keyword(s):  
Nucleotide Substitutions ◽  
Transition Mutation

Mutation Spectrum in Patients with Wiskott-Aldrich Syndrome and X-linked Thrombocytopenia: Identification of Twelve Different Mutations in the WASP Gene

1996 ◽  
Vol 75 (04) ◽  
pp. 546-550 ◽  
Author(s):  
Marianne Schwartz ◽  
Albert Békássy ◽  
Mikael Donnér ◽  
Thomas Hertel ◽  
Stefan Hreidarson ◽  
...  
Keyword(s):  
Base Pair ◽  
Hot Spot ◽  
Missense Mutations ◽  
Nucleotide Substitutions ◽  
Exon 2 ◽  
Wiskott Aldrich Syndrome ◽  
Base Pair Deletion ◽  
Reliable Diagnosis ◽  
Wasp Gene ◽  
Detection Of Mutations

SummaryTwelve different mutations in the WASP gene were found in twelve unrelated families with Wiskott-Aldrich syndrome (WAS) or X-linked thrombocytopenia (XLT). Four frameshift, one splice, one nonsense mutation, and one 18-base-pair deletion were detected in seven patients with WAS. Only missense mutations were found in five patients diagnosed as having XLT. One of the nucleotide substitutions in exon 2 (codon 86) results in an Arg to Cys replacement. Two other nucleotide substitutions in this codon, R86L and R86H, have been reported previously, both giving rise to typical WAS symptoms, indicating a mutational hot spot in this codon. The finding of mutations in the WASP gene in both WAS and XLT gives further evidence of these syndromes being allelic. The relatively small size of the WASP gene facilitates the detection of mutations and a reliable diagnosis of both carriers and affected fetuses in families with WAS or XLT.

New Nucleotide Polymorphisms in the BTC1 gene of Sugar Beet

2020 ◽  
Vol 36 (6) ◽  
pp. 49-54
Author(s):  
A.A. Nalbandyan ◽  
T.P. Fedulova ◽  
I.V. Cherepukhina ◽  
T.I. Kryukova ◽  
N.R. Mikheeva ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Flowering Time ◽  
Molecular Genetic ◽  
Bioinformatic Analysis ◽  
Early Flowering ◽  
Nucleotide Polymorphisms ◽  
Nucleotide Substitutions ◽  
Time Control ◽  
Flowering Time Control ◽  
Exon 10

The flowering time control gene of various sugar beet plants has been studied. The BTC1 gene is a regulator for the suppressor (flowering time 1) and inducer (flowering time 2) genes of this physiological process. The F9/R9 primer pair was used for polymerase chain reaction; these primers are specific to the BTC1 gene region containing exon 9, as well as intron and exon 10. For the first time, nucleotide substitutions in exon 10 of BTC1 gene were identified in bolting sensitive samples (HF1 and BF1), which led to a change in the amino acid composition of the coded polypeptide chain. Based on the results of bioinformatic analysis, it can be assumed that certain nucleotide polymorphisms in the BTC1 gene may determine with a high probability the predisposition of sugar beet genotypes to early flowering. The use of the Geneious Prime tool for the analysis of the BTC1 gene sequences may allow the culling of genotypes prone to early flowering at early stages of selection. sugar beet, flowering gene, BTC1, genetic polymorphism, PCR, molecular genetic markers, selection

Evolutionary Relationships of Major Histocompatibility Complex Class I Genes in Simian Primates

Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1897-1907
Author(s):  
Hiromi Sawai ◽  
Yoshi Kawamoto ◽  
Naoyuki Takahata ◽  
Yoko Satta
Keyword(s):  
Major Histocompatibility Complex ◽  
Distinct Group ◽  
Gene Organization ◽  
Class I ◽  
Phylogenetic Position ◽  
Specific Gene ◽  
New World Monkeys ◽  
Major Histocompatibility ◽  
Nucleotide Substitutions ◽  
Histocompatibility Complex

Abstract New World monkeys (NWMs) occupy a critical phylogenetic position in elucidating the evolutionary process of major histocompatibility complex (MHC) class I genes in primates. From three subfamilies of Aotinae, Cebinae, and Atelinae, the 5′-flanking regions of 18 class I genes are obtained and phylogenetically examined in terms of Alu/LINE insertion elements as well as the nucleotide substitutions. Two pairs of genes from Aotinae and Atelinae are clearly orthologous to human leukocyte antigen (HLA) -E and -F genes. Of the remaining 14 genes, 8 belong to the distinct group B, together with HLA-B and -C, to the exclusion of all other HLA class I genes. These NWM genes are classified into four groups, designated as NWM-B1, -B2, -B3, and -B4. Of these, NWM-B2 is orthologous to HLA-B/C. Also, orthologous relationships of NWM-B1, -B2, and -B3 exist among different families of Cebidae and Atelidae, which is in sharp contrast to the genus-specific gene organization within the subfamily Callitrichinae. The other six genes belong to the distinct group G. However, a clade of these NWM genes is almost equally related to HLA-A, -J, -G, and -K, and there is no evidence for their orthologous relationships to HLA-G. It is argued that class I genes in simian primates duplicated extensively in their common ancestral lineage and that subsequent evolution in descendant species has been facilitated mainly by independent loss of genes.

scholarly journals Evaluation of Conserved RNA Secondary Structures within and between Geographic Lineages of Zika Virus

Life ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 344
Author(s):  
Kevin Nicolas Calderon ◽  
Johan Fabian Galindo ◽  
Clara Isabel Bermudez-Santana
Keyword(s):  
Zika Virus ◽  
Rna Structure ◽  
Potential Role ◽  
Genome Structure ◽  
Nucleotide Substitutions ◽  
Genomic Comparison ◽  
Genome Variability ◽  
Vital Functions ◽  
Host Cell Interactions ◽  
Rna Genome

Zika virus (ZIKV), without a vaccine or an effective treatment approved to date, has globally spread in the last century. The infection caused by ZIKV in humans has changed progressively from mild to subclinical in recent years, causing epidemics with greater infectivity, tropism towards new tissues and other related symptoms as a product of various emergent ZIKV–host cell interactions. However, it is still unknown why or how the RNA genome structure impacts those interactions in differential evolutionary origin strains. Moreover, the genomic comparison of ZIKV strains from the sequence-based phylogenetic analysis is well known, but differences from RNA structure comparisons have barely been studied. Thus, in order to understand the RNA genome variability of lineages of various geographic distributions better, 410 complete genomes in a phylogenomic scanning were used to study the conservation of structured RNAs. Our results show the contemporary landscape of conserved structured regions with unique conserved structured regions in clades or in lineages within circulating ZIKV strains. We propose these structures as candidates for further experimental validation to establish their potential role in vital functions of the viral cycle of ZIKV and their possible associations with the singularities of different outbreaks that lead to ZIKV populations to acquire nucleotide substitutions, which is evidence of the local structure genome differentiation.

scholarly journals New Strategies to Overcome Present CRISPR/Cas9 Limitations in Apple and Pear: Efficient Dechimerization and Base Editing

2020 ◽  
Vol 22 (1) ◽  
pp. 319
Author(s):  
Jaiana Malabarba ◽  
Elisabeth Chevreau ◽  
Nicolas Dousset ◽  
Florian Veillet ◽  
Julie Moizan ◽  
...  
Keyword(s):  
Target Genes ◽  
Cytidine Deaminase ◽  
Acetolactate Synthase ◽  
Nucleotide Substitutions ◽  
Discrete Variation ◽  
Adventitious Regeneration ◽  
Base Editing ◽  
Perennial Plants ◽  
Guide Rnas ◽  
Albino Phenotype

Despite recent progress, the application of CRISPR/Cas9 in perennial plants still has many obstacles to overcome. Our previous results with CRISPR/Cas9 in apple and pear indicated the frequent production of phenotypic and genotypic chimeras, after editing of the phytoene desaturase (PDS) gene conferring albino phenotype. Therefore, our first objective was to determine if adding an adventitious regeneration step from leaves of the primary transgenic plants (T0) would allow a reduction in chimerism. Among hundreds of adventitious buds regenerated from a variegated T0 line, 89% were homogeneous albino. Furthermore, the analysis of the target zone sequences of twelve of these regenerated lines (RT0 for “regenerated T0” lines) indicated that 99% of the RT0 alleles were predicted to produce a truncated target protein and that 67% of RT0 plants had less heterogeneous editing profiles than the T0. Base editors are CRISPR/Cas9-derived new genome-editing tools that allow precise nucleotide substitutions without double-stranded breaks. Hence, our second goal was to demonstrate the feasibility of CRISPR/Cas9 base editing in apple and pear using two easily scorable genes: acetolactate synthase—ALS (conferring resistance to chlorsulfuron) and PDS. The two guide RNAs under MdU3 and MdU6 promoters were coupled into a cytidine base editor harboring a cytidine deaminase fused to a nickase Cas9. Using this vector; we induced C-to-T DNA substitutions in the target genes; leading to discrete variation in the amino-acid sequence and generating new alleles. By co-editing ALS and PDS genes; we successfully obtained chlorsulfuron resistant and albino lines in pear. Overall; our work indicates that a regeneration step can efficiently reduce the initial chimerism and could be coupled with the application of base editing to create accurate genome edits in perennial plants.

scholarly journals Molecular evolution of the plant R regulatory gene family.

Genetics ◽  
1994 ◽  
Vol 138 (3) ◽  
pp. 849-854
Author(s):  
M D Purugganan ◽  
S R Wessler
Keyword(s):  
Molecular Evolution ◽  
Gene Family ◽  
Plant Species ◽  
Regulatory Gene ◽  
Nonsynonymous Substitution ◽  
R Genes ◽  
Nucleotide Substitutions ◽  
Variable Regions ◽  
Helix Loop Helix ◽  
Regulatory Loci

Abstract Anthocyanin pigmentation patterns in different plant species are controlled in part by members of the myc-like R regulatory gene family. We have examined the molecular evolution of this gene family in seven plant species. Three regions of the R protein show sequence conservation between monocot and dicot R genes. These regions encode the basic helix-loop-helix domain, as well as conserved N-terminal and C-terminal domains; mean replacement rates for these conserved regions are 1.02 x 10(-9) nonsynonymous nucleotide substitutions per site per year. More than one-half of the protein, however, is diverging rapidly, with nonsynonymous substitution rates of 4.08 x 10(-9) substitutions per site per year. Detailed analysis of R homologs within the grasses (Poaceae) confirm that these variable regions are indeed evolving faster than the flanking conserved domains. Both nucleotide substitutions and small insertion/deletions contribute to the diversification of the variable regions within these regulatory genes. These results demonstrate that large tracts of sequence in these regulatory loci are evolving at a fairly rapid rate.

scholarly journals Mitochondrial Intronic Open Reading Frames in Podospora: Mobility and Consecutive Exonic Sequence Variations

Genetics ◽  
1996 ◽  
Vol 143 (2) ◽  
pp. 777-788 ◽  
Author(s):  
Carole H Sellem ◽  
Yves d'Aubenton-Carafa ◽  
Michèle Rossignol ◽  
Léon Belcour
Keyword(s):  
Mitochondrial Genome ◽  
Open Reading Frames ◽  
Nucleotide Substitutions ◽  
Sequence Comparisons ◽  
Modular Evolution ◽  
Group I ◽  
Sequence Variations ◽  
Type Strains ◽  
Reading Frames ◽  
Adjacent Exon

Abstract The mitochondrial genome of 23 wild-type strains belonging to three different species of The mitochondrial genome the filamentous fungus Podospora was examined. Among the 15 optional sequences identified are two intronic reading frames, nad1-i4-orf1 and cox1-i7-orf2. We show that the presence of these sequences was strictly correlated with tightly clustered nucleotide substitutions in the adjacent exon. This correlation applies to the presence or absence of closely related open reading frames (ORFs), found at the same genetic locations, in all the Pyrenomycete genera examined. The recent gain of these optional ORFs in the evolution of the genus Podospora probably account for such sequence differences. In the homoplasmic progeny from heteroplasmons constructed between Podospora strains differing by the presence of these optional ORFs, nad1-i4-orf1 and cox1-i7-orf2 appeared highly invasive. Sequence comparisons in the nad1-i4 intron of various strains of the Pyrenomycete family led us to propose a scenario of its evolution that includes several events of loss and gain of intronic ORFs. These results strongly reinforce the idea that group I intronic ORFs are mobile elements and that their transfer, and comcomitant modification of the adjacent exon, could participate in the modular evolution of mitochondrial genomes.

scholarly journals Multiple Origins of a Mitochondrial Mutation Conferring Deafness

Genetics ◽  
1997 ◽  
Vol 145 (3) ◽  
pp. 771-776 ◽  
Author(s):  
Timothy P Hutchin ◽  
Gino A Cortopassi
Keyword(s):  
Phylogenetic Analysis ◽  
Genetic Distance ◽  
Ribosomal Subunit ◽  
Sensorineural Deafness ◽  
Nucleotide Substitutions ◽  
Mitochondrial Mutation ◽  
Distance Analysis ◽  
Multiple Origins ◽  
Mtdna Haplotypes ◽  
Mtdna Sequence

A point mutation (1555G) in the smaller ribosomal subunit of the mitochondrial DNA (mtDNA) has been associated with maternally inherited traits of hypersensitivity to streptomycin and sensorineural deafness in a number of families from China, Japan, Israel, and Africa. To determine whether this distribution was the result of a single or multiple mutational events, we carried out genetic distance analysis and phylogenetic analysis of 10 independent mtDNA D-loop sequences from Africa and Asia. The mtDNA sequence diversity was high (2.21%). Phylogenetic analysis assigned 1555G-bearing haplotypes at very divergent points in the human mtDNA evolutionary tree, and the 1555G mutations occur in many cases on race-specific mtDNA haplotypes, both facts are inconsistent with a recent introgression of the mutation into these races. The simplest interpretation of the available data is that there have been multiple origins of the 1555G mutation. The genetic distance among mtDNAs bearing the pathogenic 1555G mutation is much larger than among mtDNAs bearing either evolutionarily neutral or weakly deleterious nucleotide substitutions (such as the 4336G mutation). These results are consistent with the view that pathogenic mtDNA haplotypes such as 1555G arise on disparate mtDNA lineages which because of negative natural selection leave relatively few related descendants. The co-existence of the same mutation with deafness in individuals with very different nuclear and mitochondrial genetic backgrounds confirms the pathogenicity of the 1555G mutation.

scholarly journals Description of optochin-resistant Streptococcus pneumoniae due to an uncommon mutation in the atpA gene and comparison with previously identified atpC mutants from Brazil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aline R. V. Souza ◽  
Sandrine E. C. M. de Pina ◽  
Natália S. Costa ◽  
Felipe P. G. Neves ◽  
Vânia L. C. Merquior ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Susceptibility Testing ◽  
Protein Structures ◽  
Selective Advantage ◽  
Nucleotide Substitutions ◽  
Genetic Characteristics ◽  
Structural Alterations ◽  
C Subunit ◽  
Atpa Gene ◽  
A Subunit

AbstractOptochin susceptibility testing is a major assay used for presumptive identification of Streptococcus pneumoniae. Still, atypical optochin-resistant (Optr) pneumococci have been reported and this phenotype has been attributed to nucleotide substitutions in the genes coding for the F0F1ATPase. While substitutions in the atpC gene (c-subunit of ATPase) are more common and better characterized, data on mutations in the atpA (a-subunit) are still limited. We have characterized five Optr isolates presenting alterations in the atpA (Trp206Cys in four isolates and Trp206Ser in one isolate), constituting the first report of such mutations in Brazil. Most of the Optr isolates consisted of heterogeneous populations. Except for Opt MICs and the nucleotide changes in the atpA gene, Optr and Opts subpopulations originating from the same culture had identical characteristics. In addition, we compared phenotypic and genetic characteristics of these atpA mutants with those of atpC mutants previously identified in Brazil. No structural alterations were detected among predicted proteins, regardless of mutations in the coding gene, suggesting that, despite the occurrence of mutations, protein structures tend to be highly conserved, ensuring their functionalities. Phylogenetic analysis revealed that atypical Optr strains are true pneumococci and Opt resistance does not represent any apparent selective advantage for clinical isolates.

Sign in / Sign up

Export Citation Format

Share Document