scholarly journals Evidence of extensive intraspecific noncoding reshuffling in a 169-kb mitochondrial genome of a basidiomycetous fungus

2019 ◽  
Author(s):  
Hsin-Han Lee ◽  
Huei-Mien Ke ◽  
Chan-Yi Ivy Lin ◽  
Tracy J. Lee ◽  
Chia-Lin Chung ◽  
...  
Keyword(s):  
Size Variation ◽  
Sequence Divergence ◽  
Mitochondrial Genomes ◽  
Intergenic Sequence ◽  
Evolutionary Time ◽  
Protein Coding ◽  
Genetic Lineages ◽  
Basidiomycetous Fungus ◽  
Mtdna Inheritance

AbstractComparative genomics of fungal mitochondrial genomes (mitogenomes) have revealed a remarkable pattern of rearrangement between and within major phyla owing to horizontal gene transfer (HGT) and recombination. The role of recombination was exemplified at a finer evolutionary time scale in basidiomycetes group of fungi as they display a diversity of mitochondrial DNA (mtDNA) inheritance patterns. Here, we assembled mitogenomes of six species from the Hymenochaetales order of basidiomycetes and examined 59 mitogenomes from two genetic lineages ofPyrrhoderma noxium. Gene order is largely colinear while intergene regions are major determinants of mitogenome size variation. Substantial sequence divergence was found in shared introns consistent with high HGT frequency observed in yeasts, but we also identified a rare case where an intron was retained in five species since speciation. In contrast to the hyperdiversity observed in nuclear genomes ofP. noxium, mitogenomes’ intraspecific polymorphisms at protein coding sequences are extremely low. Phylogeny based on introns revealed turnover as well as exchange of introns between two lineages. Strikingly, some strains harbor a mosaic origin of introns from both lineages. Analysis of intergenic sequence indicated substantial differences between and within lineages, and an expansion may be ongoing as a result of exchange between distal intergenes. These findings suggest that the evolution in mtDNAs is usually lineage specific but chimeric mitotypes are frequently observed, thus capturing the possible evolutionary processes shaping mitogenomes in a basidiomycete. The large mitogenome sizes reported in various basidiomycetes appear to be a result of interspecific reshuffling of intergenes.

scholarly journals Evidence of Extensive Intraspecific Noncoding Reshuffling in a 169-kb Mitochondrial Genome of a Basidiomycetous Fungus

2019 ◽  
Vol 11 (10) ◽  
pp. 2774-2788 ◽  
Author(s):  
Hsin-Han Lee ◽  
Huei-Mien Ke ◽  
Chan-Yi Ivy Lin ◽  
Tracy J Lee ◽  
Chia-Lin Chung ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Size Variation ◽  
Sequence Divergence ◽  
Intergenic Sequence ◽  
Protein Coding ◽  
Genetic Lineages ◽  
Basidiomycetous Fungus ◽  
Mitochondrial Dnas ◽  
Phellinus Noxius

Abstract Comparative genomics of fungal mitochondrial genomes (mitogenomes) have revealed a remarkable pattern of rearrangement between and within major phyla owing to horizontal gene transfer and recombination. The role of recombination was exemplified at a finer evolutionary time scale in basidiomycetes group of fungi as they display a diversity of mitochondrial DNA inheritance patterns. Here, we assembled mitogenomes of six species from the Hymenochaetales order of basidiomycetes and examined 59 mitogenomes from 2 genetic lineages of Phellinus noxius. Gene order is largely collinear, while intergene regions are major determinants of mitogenome size variation. Substantial sequence divergence was found in shared introns consistent with high horizontal gene transfer frequency observed in yeasts, but we also identified a rare case where an intron was retained in five species since speciation. In contrast to the hyperdiversity observed in nuclear genomes of Phellinus noxius, mitogenomes’ intraspecific polymorphisms at protein-coding sequences are extremely low. Phylogeny network based on introns revealed turnover as well as exchange of introns between two lineages. Strikingly, some strains harbor a mosaic origin of introns from both lineages. Analysis of intergenic sequence indicated substantial differences between and within lineages, and an expansion may be ongoing as a result of exchange between distal intergenes. These findings suggest that the evolution in mitochondrial DNAs is usually lineage specific but chimeric mitotypes are frequently observed, thus capturing the possible evolutionary processes shaping mitogenomes in a basidiomycete. The large mitogenome sizes reported in various basidiomycetes appear to be a result of interspecific reshuffling of intergenes.

Evolution of primate orphan proteins

2009 ◽  
Vol 37 (4) ◽  
pp. 778-782 ◽  
Author(s):  
Macarena Toll-Riera ◽  
Robert Castelo ◽  
Nicolás Bellora ◽  
M. Mar Albà
Keyword(s):  
Related Species ◽  
Sequence Divergence ◽  
Orphan Genes ◽  
Closely Related Species ◽  
Protein Coding ◽  
Rapid Sequence ◽  
Adaptive Processes ◽  
Mechanisms Of Formation ◽  
Novel Protein

Genomes contain a large number of genes that do not have recognizable homologues in other species. These genes, found in only one or a few closely related species, are known as orphan genes. Their limited distribution implies that many of them are probably involved in lineage-specific adaptive processes. One important question that has remained elusive to date is how orphan genes originate. It has been proposed that they might have arisen by gene duplication followed by a period of very rapid sequence divergence, which would have erased any traces of similarity to other evolutionarily related genes. However, this explanation does not seem plausible for genes lacking homologues in very closely related species. In the present article, we review recent efforts to identify the mechanisms of formation of primate orphan genes. These studies reveal an unexpected important role of transposable elements in the formation of novel protein-coding genes in the genomes of primates.

scholarly journals Conserved novel ORFs in the mitochondrial genome of the ctenophore Beroe forskalii

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8356
Author(s):  
Darrin T. Schultz ◽  
Jordan M. Eizenga ◽  
Russell B. Corbett-Detig ◽  
Warren R. Francis ◽  
Lynne M. Christianson ◽  
...  
Keyword(s):  
Mitochondrial Genome ◽  
Hypothesis Test ◽  
Open Reading Frames ◽  
Mitochondrial Genomes ◽  
Intergenic Sequence ◽  
Computational Tools ◽  
Protein Coding ◽  
Bayesian Hypothesis Test ◽  
And Function ◽  
Reading Frames

To date, five ctenophore species’ mitochondrial genomes have been sequenced, and each contains open reading frames (ORFs) that if translated have no identifiable orthologs. ORFs with no identifiable orthologs are called unidentified reading frames (URFs). If truly protein-coding, ctenophore mitochondrial URFs represent a little understood path in early-diverging metazoan mitochondrial evolution and metabolism. We sequenced and annotated the mitochondrial genomes of three individuals of the beroid ctenophore Beroe forskalii and found that in addition to sharing the same canonical mitochondrial genes as other ctenophores, the B. forskalii mitochondrial genome contains two URFs. These URFs are conserved among the three individuals but not found in other sequenced species. We developed computational tools called pauvre and cuttlery to determine the likelihood that URFs are protein coding. There is evidence that the two URFs are under negative selection, and a novel Bayesian hypothesis test of trinucleotide frequency shows that the URFs are more similar to known coding genes than noncoding intergenic sequence. Protein structure and function prediction of all ctenophore URFs suggests that they all code for transmembrane transport proteins. These findings, along with the presence of URFs in other sequenced ctenophore mitochondrial genomes, suggest that ctenophores may have uncharacterized transmembrane proteins present in their mitochondria.

scholarly journals Mitogenomic analysis of a 50-generation chicken pedigree reveals a rapid rate of mitochondrial evolution and evidence for paternal mtDNA inheritance

2015 ◽  
Vol 11 (10) ◽  
pp. 20150561 ◽  
Author(s):  
Michelle Alexander ◽  
Simon Y. W. Ho ◽  
Martyna Molak ◽  
Ross Barnett ◽  
Örjan Carlborg ◽  
...  
Keyword(s):  
Point Mutations ◽  
Mitochondrial Genomes ◽  
Synonymous Mutation ◽  
Novel Mutations ◽  
Short Term ◽  
Mitochondrial Evolution ◽  
Phenotypic Differences ◽  
Mtdna Inheritance ◽  
Short Time

Mitochondrial genomes represent a valuable source of data for evolutionary research, but studies of their short-term evolution have typically been limited to invertebrates, humans and laboratory organisms. Here we present a detailed study of 12 mitochondrial genomes that span a total of 385 transmissions in a well-documented 50-generation pedigree in which two lineages of chickens were selected for low and high juvenile body weight. These data allowed us to test the hypothesis of time-dependent evolutionary rates and the assumption of strict maternal mitochondrial transmission, and to investigate the role of mitochondrial mutations in determining phenotype. The identification of a non-synonymous mutation in ND4L and a synonymous mutation in CYTB , both novel mutations in Gallus , allowed us to estimate a molecular rate of 3.13 × 10 −7 mutations/site/year (95% confidence interval 3.75 × 10 −8 –1.12 × 10 −6 ). This is substantially higher than avian rate estimates based upon fossil calibrations. Ascertaining which of the two novel mutations was present in an additional 49 individuals also revealed an instance of paternal inheritance of mtDNA. Lastly, an association analysis demonstrated that neither of the point mutations was strongly associated with the phenotypic differences between the two selection lines. Together, these observations reveal the highly dynamic nature of mitochondrial evolution over short time periods.

scholarly journals Variation in Plastome Sizes Accompanied by Evolutionary History in Monogenomic Triticeae (Poaceae: Triticeae)

2021 ◽  
Vol 12 ◽  
Author(s):  
Ning Chen ◽  
Li-Na Sha ◽  
Yi-Ling Wang ◽  
Ling-Juan Yin ◽  
Yue Zhang ◽  
...  
Keyword(s):  
Chloroplast Genome ◽  
Genome Size ◽  
Divergence Time ◽  
Size Variation ◽  
Intergenic Sequence ◽  
Protein Coding ◽  
Ancestral Genome Reconstruction ◽  
Adaptive Processes ◽  
Intergenic Regions ◽  
Plastid Genome Evolution

To investigate the pattern of chloroplast genome variation in Triticeae, we comprehensively analyzed the indels in protein-coding genes and intergenic sequence, gene loss/pseudonization, intron variation, expansion/contraction in inverted repeat regions, and the relationship between sequence characteristics and chloroplast genome size in 34 monogenomic Triticeae plants. Ancestral genome reconstruction suggests that major length variations occurred in four-stem branches of monogenomic Triticeae followed by independent changes in each genus. It was shown that the chloroplast genome sizes of monogenomic Triticeae were highly variable. The chloroplast genome of Pseudoroegneria, Dasypyrum, Lophopyrum, Thinopyrum, Eremopyrum, Agropyron, Australopyrum, and Henradia in Triticeae had evolved toward size reduction largely because of pseudogenes elimination events and length deletion fragments in intergenic. The Aegilops/Triticum complex, Taeniatherum, Secale, Crithopsis, Herteranthelium, and Hordeum in Triticeae had a larger chloroplast genome size. The large size variation in major lineages and their subclades are most likely consequences of adaptive processes since these variations were significantly correlated with divergence time and historical climatic changes. We also found that several intergenic regions, such as petN–trnC and psbE–petL containing unique genetic information, which can be used as important tools to identify the maternal relationship among Triticeae species. Our results contribute to the novel knowledge of plastid genome evolution in Triticeae.

scholarly journals The massive mitochondrial genome of the angiosperm Silene noctiflora is evolving by gain or loss of entire chromosomes

2015 ◽  
Vol 112 (33) ◽  
pp. 10185-10191 ◽  
Author(s):  
Zhiqiang Wu ◽  
Jocelyn M. Cuthbert ◽  
Douglas R. Taylor ◽  
Daniel B. Sloan
Keyword(s):  
Mitochondrial Genome ◽  
Sequence Divergence ◽  
Duplicate Gene ◽  
Mitochondrial Genomes ◽  
Protein Coding ◽  
Gene Copies ◽  
Repeated Evolution ◽  
Multiple Species ◽  
Gain Loss ◽  
High Degree

Across eukaryotes, mitochondria exhibit staggering diversity in genomic architecture, including the repeated evolution of multichromosomal structures. Unlike in the nucleus, where mitosis and meiosis ensure faithful transmission of chromosomes, the mechanisms of inheritance in fragmented mitochondrial genomes remain mysterious. Multichromosomal mitochondrial genomes have recently been found in multiple species of flowering plants, including Silene noctiflora, which harbors an unusually large and complex mitochondrial genome with more than 50 circular-mapping chromosomes totaling ∼7 Mb in size. To determine the extent to which such genomes are stably maintained, we analyzed intraspecific variation in the mitochondrial genome of S. noctiflora. Complete genomes from two populations revealed a high degree of similarity in the sequence, structure, and relative abundance of mitochondrial chromosomes. For example, there are no inversions between the genomes, and there are only nine SNPs in 25 kb of protein-coding sequence. Remarkably, however, these genomes differ in the presence or absence of 19 entire chromosomes, all of which lack any identifiable genes or contain only duplicate gene copies. Thus, these mitochondrial genomes retain a full gene complement but carry a highly variable set of chromosomes that are filled with presumably dispensable sequence. In S. noctiflora, conventional mechanisms of mitochondrial sequence divergence are being outstripped by an apparently nonadaptive process of whole-chromosome gain/loss, highlighting the inherent challenge in maintaining a fragmented genome. We discuss the implications of these findings in relation to the question of why mitochondria, more so than plastids and bacterial endosymbionts, are prone to the repeated evolution of multichromosomal genomes.

scholarly journals Sex-limited mitochondrial DNA transmission in the marine mussel Mytilus edulis.

Genetics ◽  
1994 ◽  
Vol 138 (3) ◽  
pp. 801-809 ◽  
Author(s):  
D O Skibinski ◽  
C Gallagher ◽  
C M Beynon
Keyword(s):  
Mitochondrial Dna ◽  
Direct Evidence ◽  
Sequence Divergence ◽  
Marine Mussel ◽  
Protein Coding ◽  
Mtdna Inheritance ◽  
A Genome ◽  
Males And Females ◽  
Term Maintenance

Abstract Mitochondrial DNA (mtDNA) was thought to be inherited maternally in animals, although paternal leakage has been reported in mice and Drosophila. Recently, direct evidence of extensive paternal inheritance of mtDNA has been found in the marine mussel Mytilus. We give evidence that whereas female mussels are homoplasmic for a genome that is transmitted to eggs, male mussels are heteroplasmic for this genome and for a second genome that is transmitted preferentially to sperm. The results provide support for the existence of separate male and female routes of mtDNA inheritance in mussels. The two genomes show a base sequence divergence exceeding 20% at three protein coding genes, consistent with long term maintenance of the heteroplasmic state. We propose that the two genomes differ in fitness in males and females, possibly as a result of interaction with nuclear genes.

scholarly journals Two Complete Mitochondrial Genomes of Mileewinae (Hemiptera: Cicadellidae) and a Phylogenetic Analysis

Insects ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 668
Author(s):  
Tinghao Yu ◽  
Yalin Zhang
Keyword(s):  
Phylogenetic Analysis ◽  
Phylogenetic Relationships ◽  
Phylogenetic Trees ◽  
Strong Support ◽  
Intergenic Spacer ◽  
Taxonomic Status ◽  
Start Codon ◽  
Gene Arrangement ◽  
Mitochondrial Genomes ◽  
Protein Coding

More studies are using mitochondrial genomes of insects to explore the sequence variability, evolutionary traits, monophyly of groups and phylogenetic relationships. Controversies remain on the classification of the Mileewinae and the phylogenetic relationships between Mileewinae and other subfamilies remain ambiguous. In this study, we present two newly completed mitogenomes of Mileewinae (Mileewa rufivena Cai and Kuoh 1997 and Ujna puerana Yang and Meng 2010) and conduct comparative mitogenomic analyses based on several different factors. These species have quite similar features, including their nucleotide content, codon usage of protein genes and the secondary structure of tRNA. Gene arrangement is identical and conserved, the same as the putative ancestral pattern of insects. All protein-coding genes of U. puerana began with the start codon ATN, while 5 Mileewa species had the abnormal initiation codon TTG in ND5 and ATP8. Moreover, M. rufivena had an intergenic spacer of 17 bp that could not be found in other mileewine species. Phylogenetic analysis based on three datasets (PCG123, PCG12 and AA) with two methods (maximum likelihood and Bayesian inference) recovered the Mileewinae as a monophyletic group with strong support values. All results in our study indicate that Mileewinae has a closer phylogenetic relationship to Typhlocybinae compared to Cicadellinae. Additionally, six species within Mileewini revealed the relationship (U. puerana + (M. ponta + (M. rufivena + M. alara) + (M. albovittata + M. margheritae))) in most of our phylogenetic trees. These results contribute to the study of the taxonomic status and phylogenetic relationships of Mileewinae.

scholarly journals Long non-coding RNA LINC00665 promotes gemcitabine resistance of Cholangiocarcinoma cells via regulating EMT and stemness properties through miR-424-5p/BCL9L axis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Min Lu ◽  
Xinglei Qin ◽  
Yajun Zhou ◽  
Gang Li ◽  
Zhaoyang Liu ◽  
...  
Keyword(s):  
Acquired Resistance ◽  
Transcriptional Regulators ◽  
First Line ◽  
Protein Coding ◽  
Gemcitabine Resistance ◽  
Non Coding Rna ◽  
Sphere Formation ◽  
Long Non Coding Rna ◽  
Line Chemotherapy

AbstractGemcitabine is the first-line chemotherapy drug for cholangiocarcinoma (CCA), but acquired resistance has been frequently observed in CCA patients. To search for potential long noncoding RNAs (lncRNAs) involved in gemcitabine resistance, two gemcitabine resistant CCA cell lines were established and dysregulated lncRNAs were identified by lncRNA microarray. Long intergenic non-protein coding RNA 665 (LINC00665) were found to rank the top 10 upregulated lncRNAs in our study, and high LINC00665 expression was closely associated with poor prognosis and chemoresistance of CCA patients. Silencing LINC00665 in gemcitabine resistant CCA cells impaired gemcitabine tolerance, while enforced LINC00665 expression increased gemcitabine resistance of sensitive CCA cells. The gemcitabine resistant CCA cells showed increased EMT and stemness properties, and silencing LINC00665 suppressed sphere formation, migration, invasion and expression of EMT and stemness markers. In addition, Wnt/β-Catenin signaling was activated in gemcitabine resistant CCA cells, but LINC00665 knockdown suppressed Wnt/β-Catenin activation. B-cell CLL/lymphoma 9-like (BCL9L), the nucleus transcriptional regulators of Wnt/β-Catenin signaling, plays a key role in the nucleus translocation of β-Catenin and promotes β-Catenin-dependent transcription. In our study, we found that LINC00665 regulated BCL9L expression by acting as a molecular sponge for miR-424-5p. Moreover, silencing BCL9L or miR-424-5p overexpression suppressed gemcitabine resistance, EMT, stemness and Wnt/β-Catenin activation in resistant CCA cells. In conclusion, our results disclosed the important role of LINC00665 in gemcitabine resistance of CCA cells, and provided a new biomarker or therapeutic target for CCA treament.

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