scholarly journals The birth of a bacterial tRNA gene by large-scale, tandem duplication events

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Gökçe B Ayan ◽  
Hye Jin Park ◽  
Jenna Gallie
Keyword(s):  
Large Scale ◽  
Trna Gene ◽  
Single Copy ◽  
Growth Defect ◽  
Trna Genes ◽  
Evolutionary Mechanisms ◽  
Gene Set ◽  
Gene Copies ◽  
Laboratory Populations ◽  
Duplication Events

Organisms differ in the types and numbers of tRNA genes that they carry. While the evolutionary mechanisms behind tRNA gene set evolution have been investigated theoretically and computationally, direct observations of tRNA gene set evolution remain rare. Here, we report the evolution of a tRNA gene set in laboratory populations of the bacterium Pseudomonas fluorescens SBW25. The growth defect caused by deleting the single-copy tRNA gene, serCGA, is rapidly compensated by large-scale (45–290 kb) duplications in the chromosome. Each duplication encompasses a second, compensatory tRNA gene (serTGA) and is associated with a rise in tRNA-Ser(UGA) in the mature tRNA pool. We postulate that tRNA-Ser(CGA) elimination increases the translational demand for tRNA-Ser(UGA), a pressure relieved by increasing serTGA copy number. This work demonstrates that tRNA gene sets can evolve through duplication of existing tRNA genes, a phenomenon that may contribute to the presence of multiple, identical tRNA gene copies within genomes.

scholarly journals The birth of a bacterial tRNA gene by large-scale, tandem duplication events

2020 ◽  
Author(s):  
Gökçe B. Ayan ◽  
Hye Jin Park ◽  
Jenna Gallie
Keyword(s):  
Large Scale ◽  
Trna Gene ◽  
Single Copy ◽  
Growth Defect ◽  
Trna Genes ◽  
Evolutionary Mechanisms ◽  
Gene Set ◽  
Gene Copies ◽  
Laboratory Populations ◽  
Duplication Events

ABSTRACTOrganisms differ in the types and numbers of tRNA genes that they carry. While the evolutionary mechanisms behind tRNA gene set evolution have been investigated theoretically and computationally, direct observations of tRNA gene set evolution remain rare. Here, we report the evolution of a tRNA gene set in laboratory populations of the bacterium Pseudomonas fluorescens SBW25. The growth defect caused by deleting the single-copy tRNA gene, serCGA, is rapidly compensated by large-scale (45-290 kb) duplications in the chromosome. Each duplication encompasses a second, compensatory tRNA gene (serTGA) and is associated with a rise in tRNA-Ser(UGA) in the mature tRNA pool. We postulate that tRNA-Ser(CGA) elimination increases the translational demand for tRNA-Ser(UGA), a pressure relieved by increasing serTGA copy number. This work demonstrates that tRNA gene sets can evolve through duplication of existing tRNA genes, a phenomenon that may contribute to the presence of multiple, identical tRNA gene copies within genomes.

scholarly journals Global In-Silico Scenario of tRNA Genes and Their Organization in Virus Genomes

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 180 ◽  
Author(s):  
Sergio Morgado ◽  
Ana Vicente
Keyword(s):  
In Silico ◽  
Large Scale ◽  
Trna Gene ◽  
Gene Clusters ◽  
Trna Genes ◽  
Genome Survey ◽  
In Silico Study ◽  
Domains Of Life ◽  
Dsdna Viruses ◽  
Virus Genomes

Viruses are known to be highly dependent on the host translation machinery for their protein synthesis. However, tRNA genes are occasionally identified in such organisms, and in addition, few of them harbor tRNA gene clusters comprising dozens of genes. Recently, tRNA gene clusters have been shown to occur among the three domains of life. In such a scenario, the viruses could play a role in the dispersion of such structures among these organisms. Thus, in order to reveal the prevalence of tRNA genes as well as tRNA gene clusters in viruses, we performed an unbiased large-scale genome survey. Interestingly, tRNA genes were predicted in ssDNA (single-stranded DNA) and ssRNA (single-stranded RNA) viruses as well in many other dsDNA viruses of families from Caudovirales order. In the latter group, tRNA gene clusters composed of 15 to 37 tRNA genes were characterized, mainly in bacteriophages, enlarging the occurrence of such structures within viruses. These bacteriophages were from hosts that encompass five phyla and 34 genera. This in-silico study presents the current global scenario of tRNA genes and their organization in virus genomes, contributing and opening questions to be explored in further studies concerning the role of the translation apparatus in these organisms.

scholarly journals Two ancient genome duplication events shape diversity in Hibiscus L. (Malvaceae)

2020 ◽  
Author(s):  
Jonna Sofia Eriksson ◽  
Christine D. Bacon ◽  
Dominic J. Bennett ◽  
Bernard E. Pfeil ◽  
Bengt Oxelman ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Genome Size ◽  
Genome Duplication ◽  
Single Copy ◽  
Genomic Diversity ◽  
Plant Genome ◽  
Genome Doubling ◽  
Gene Copies ◽  
Plant Groups ◽  
Duplication Events

Abstract Background: The great diversity in plant genome size and chromosome number is partly due to polyploidization (i.e., genome doubling events). The differences in genome size and chromosome number among diploid plant species can be a window into the intriguing phenomenon of past genome doubling that may be obscured through time by the process of diploidization. The genus Hibiscus L. (Malvaceae) has a wide diversity of chromosome numbers and an allegedly complex genomic history. Hibiscus is ideal for exploring past genomic events because although two ancient genome duplication events have been identified, as more are still likely to be found, considering its diverse background. To reappraise the group’s genomic history, we tested a series of scenarios describing different polyploidization events using previously identified duplications in Hibiscus syriacus.Results: The data showed that >54% of the single-copy genes where in fact paralogues. When testing for different genome duplication scenarios using gene count data; species of Hibiscus was shown to have shared one genome duplication with H. syriacus, -- while one whole genome duplication was contained within H. syriacus, -- to be the preferred model given the observed distribution of paralogous gene copies in Hibiscus.Conclusions: Here, we corroborated the independent genome doubling previously found in the lineage leading to H. syriacus and a shared genome doubling of this lineage and the remainder of Hibiscus. Additionally, we found a previously undiscovered genome duplication shared by the /Pavonia and /Malvaviscus clades (both nested within Hibiscus) with the occurrences of two copies in what were otherwise single-copy genes. Our results highlight the complexity of genomic diversity in some plant groups, which makes orthology assessment and accurate phylogenomic inference difficult.

scholarly journals The Chloroplast Phylogenomics and Systematics of Zoysia (Poaceae)

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1517
Author(s):  
Se-Hwan Cheon ◽  
Min-Ah Woo ◽  
Sangjin Jo ◽  
Young-Kee Kim ◽  
Ki-Joong Kim
Keyword(s):  
Northeast Asia ◽  
Single Copy ◽  
Rrna Genes ◽  
Bootstrap Support ◽  
Trna Genes ◽  
Protein Coding ◽  
Tropical Regions ◽  
Relationship Of ◽  
The Relationship ◽  
Simple Sequence

The genus Zoysia Willd. (Chloridoideae) is widely distributed from the temperate regions of Northeast Asia—including China, Japan, and Korea—to the tropical regions of Southeast Asia. Among these, four species—Zoysia japonica Steud., Zoysia sinica Hance, Zoysia tenuifolia Thiele, and Zoysia macrostachya Franch. & Sav.—are naturally distributed in the Korean Peninsula. In this study, we report the complete plastome sequences of these Korean Zoysia species (NCBI acc. nos. MF953592, MF967579~MF967581). The length of Zoysia plastomes ranges from 135,854 to 135,904 bp, and the plastomes have a typical quadripartite structure, which consists of a pair of inverted repeat regions (20,962~20,966 bp) separated by a large (81,348~81,392 bp) and a small (12,582~12,586 bp) single-copy region. In terms of gene order and structure, Zoysia plastomes are similar to the typical plastomes of Poaceae. The plastomes encode 110 genes, of which 76 are protein-coding genes, 30 are tRNA genes, and four are rRNA genes. Fourteen genes contain single introns and one gene has two introns. Three evolutionary hotspot spacer regions—atpB~rbcL, rps16~rps3, and rpl32~trnL-UAG—were recognized among six analyzed Zoysia species. The high divergences in the atpB~rbcL spacer and rpl16~rpl3 region are primarily due to the differences in base substitutions and indels. In contrast, the high divergence between rpl32~trnL-UAG spacers is due to a small inversion with a pair of 22 bp stem and an 11 bp loop. Simple sequence repeats (SSRs) were identified in 59 different locations in Z. japonica, 63 in Z. sinica, 62 in Z. macrostachya, and 63 in Z. tenuifolia plastomes. Phylogenetic analysis showed that the Zoysia (Zoysiinae) forms a monophyletic group, which is sister to Sporobolus (Sporobolinae), with 100% bootstrap support. Within the Zoysia clade, the relationship of (Z. sinica, Z japonica), (Z. tenuifolia, Z. matrella), (Z. macrostachya, Z. macrantha) was suggested.

scholarly journals Frequent tRNA gene translocation towards the boundaries with control regions contributes to the highly dynamic mitochondrial genome organization of the parasitic lice of mammals

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Wen-Ge Dong ◽  
Yalun Dong ◽  
Xian-Guo Guo ◽  
Renfu Shao
Keyword(s):  
Mitochondrial Genome ◽  
Control Region ◽  
Genome Organization ◽  
Trna Gene ◽  
Trna Genes ◽  
Single Chromosome ◽  
Gene Translocation ◽  
Sucking Lice ◽  
Different Types ◽  
Mt Genome

Abstract Background The typical single-chromosome mitochondrial (mt) genome of animals has fragmented into multiple minichromosomes in the lineage Mitodivisia, which contains most of the parasitic lice of eutherian mammals. These parasitic lice differ from each other even among congeneric species in mt karyotype, i.e. the number of minichromosomes, and the gene content and gene order in each minichromosome, which is in stark contrast to the extremely conserved single-chromosome mt genomes across most animal lineages. How fragmented mt genomes evolved is still poorly understood. We use Polyplax sucking lice as a model to investigate how tRNA gene translocation shapes the dynamic mt karyotypes. Results We sequenced the full mt genome of the Asian grey shrew louse, Polyplax reclinata. We then inferred the ancestral mt karyotype for Polyplax lice and compared it with the mt karyotypes of the three Polyplax species sequenced to date. We found that tRNA genes were entirely responsible for mt karyotype variation among these three species of Polyplax lice. Furthermore, tRNA gene translocation observed in Polyplax lice was only between different types of minichromosomes and towards the boundaries with the control region. A similar pattern of tRNA gene translocation can also been seen in other sucking lice with fragmented mt genomes. Conclusions We conclude that inter-minichromosomal tRNA gene translocation orientated towards the boundaries with the control region is a major contributing factor to the highly dynamic mitochondrial genome organization in the parasitic lice of mammals.

scholarly journals Mangrove tree (Avicennia marina): insight into chloroplast genome evolutionary divergence and its comparison with related species from family Acanthaceae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sajjad Asaf ◽  
Abdul Latif Khan ◽  
Muhammad Numan ◽  
Ahmed Al-Harrasi
Keyword(s):  
Chloroplast Genome ◽  
Related Species ◽  
Evolutionary Genetics ◽  
Single Copy ◽  
Avicennia Marina ◽  
Pairwise Distance ◽  
Trna Genes ◽  
Evolutionary Divergence ◽  
Mangrove Tree ◽  
High Degree

AbstractAvicennia marina (family Acanthaceae) is a halotolerant woody shrub that grows wildly and cultivated in the coastal regions. Despite its importance, the species suffers from lack of genomic datasets to improve its taxonomy and phylogenetic placement across the related species. Here, we have aimed to sequence the plastid genome of A. marina and its comparison with related species in family Acanthaceae. Detailed next-generation sequencing and analysis showed a complete chloroplast genome of 150,279 bp, comprising 38.6% GC. Genome architecture is quadripartite revealing large single copy (82,522 bp), small single copy (17,523 bp), and pair of inverted repeats (25,117 bp). Furthermore, the genome contains 132 different genes, including 87 protein-coding genes, 8 rRNA, 37 tRNA genes, and 126 simple sequence repeats (122 mononucleotide, 2 dinucleotides, and 2 trinucleotides). Interestingly, about 25 forward, 15 reversed and 14 palindromic repeats were also found in the A. marina. High degree synteny was observed in the pairwise alignment with related genomes. The chloroplast genome comparative assessment showed a high degree of sequence similarity in coding regions and varying divergence in the intergenic spacers among ten Acanthaceae species. The pairwise distance showed that A. marina exhibited the highest divergence (0.084) with Justicia flava and showed lowest divergence with Aphelandra knappiae (0.059). Current genomic datasets are a valuable resource for investigating the population and evolutionary genetics of family Acanthaceae members’ specifically A. marina and related species.

scholarly journals The Complete Chloroplast Genome of the Vulnerable Oreocharis esquirolii (Gesneriaceae): Structural Features, Comparative and Phylogenetic Analysis

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1692
Author(s):  
Li Gu ◽  
Ting Su ◽  
Ming-Tai An ◽  
Guo-Xiong Hu
Keyword(s):  
Phylogenetic Analysis ◽  
Sequence Similarity ◽  
Single Copy ◽  
Structural Features ◽  
Rrna Genes ◽  
Trna Genes ◽  
Sequencing Data ◽  
High Sequence Similarity ◽  
Plastid Genomes ◽  
Cp Genome

Oreocharis esquirolii, a member of Gesneriaceae, is known as Thamnocharis esquirolii, which has been regarded a synonym of the former. The species is endemic to Guizhou, southwestern China, and is evaluated as vulnerable (VU) under the International Union for Conservation of Nature (IUCN) criteria. Until now, the sequence and genome information of O. esquirolii remains unknown. In this study, we assembled and characterized the complete chloroplast (cp) genome of O. esquirolii using Illumina sequencing data for the first time. The total length of the cp genome was 154,069 bp with a typical quadripartite structure consisting of a pair of inverted repeats (IRs) of 25,392 bp separated by a large single copy region (LSC) of 85,156 bp and a small single copy region (SSC) of18,129 bp. The genome comprised 114 unique genes with 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. Thirty-one repeat sequences and 74 simple sequence repeats (SSRs) were identified. Genome alignment across five plastid genomes of Gesneriaceae indicated a high sequence similarity. Four highly variable sites (rps16-trnQ, trnS-trnG, ndhF-rpl32, and ycf 1) were identified. Phylogenetic analysis indicated that O. esquirolii grouped together with O. mileensis, supporting resurrection of the name Oreocharis esquirolii from Thamnocharisesquirolii. The complete cp genome sequence will contribute to further studies in molecular identification, genetic diversity, and phylogeny.

scholarly journals Effect of intron mutations on processing and function of Saccharomyces cerevisiae SUP53 tRNA in vitro and in vivo.

1986 ◽  
Vol 6 (7) ◽  
pp. 2663-2673 ◽  
Author(s):  
M C Strobel ◽  
J Abelson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Trna Gene ◽  
Nuclear Extract ◽  
Nonsense Suppression ◽  
Trna Genes ◽  
Suppressor Activity ◽  
Specific Sequence ◽  
Made In

The Saccharomyces cerevisiae leucine-inserting amber suppressor tRNA gene SUP53 (a tRNALeu3 allele) was used to investigate the relationship between precursor tRNA structure and mature tRNA function. This gene encodes a pre-tRNA which contains a 32-base intron. The mature tRNASUP53 contains a 5-methylcytosine modification of the anticodon wobble base. Mutations were made in the SUP53 intron. These mutant genes were transcribed in an S. cerevisiae nuclear extract preparation. In this extract, primary tRNA gene transcripts are end-processed and base modified after addition of cofactors. The base modifications made in vitro were examined, and the mutant pre-tRNAs were analyzed for their ability to serve as substrates for partially purified S. cerevisiae tRNA endonuclease and ligase. Finally, the suppressor function of these mutant tRNA genes was assayed after their integration into the S. cerevisiae genome. Mutant analysis showed that the totally intact precursor tRNA, rather than any specific sequence or structure of the intron, was necessary for efficient nonsense suppression by tRNASUP53. Less efficient suppressor activity correlated with the absence of the 5-methylcytosine modification. Most of the intron-altered precursor tRNAs were successfully spliced in vitro, indicating that modifications are not critical for recognition by the tRNA endonuclease and ligase.

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